Latest / Ducks Unlimited Podcast / Ep. 548 – Species Profile: Brant (re-air)

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Ep. 548 – Species Profile: Brant (re-air) · Ducks Unlimited Podcast

• Mike Brasher: Hey everybody, this is Dr. Mike Brazier, and today we have a re-air of one of our species profiles. Brandt is the species we're going to be talking about. This originally aired back in October of 2022 as two separate episodes, but this conversation is timely again now here in early 2024, and so we have repackaged this as one single episode. We've trimmed a little bit of information from it, but we know it's still going to be very popular and very informative. So, sit back, relax, grab a bag of popcorn if you'd like, and enjoy the episode. Hey everybody, welcome back. We have another one of our species profile episodes today, and this one is pretty special from a personal standpoint because of a recent trip that I went on. We're recording this on October 27th, and just last week, just about five days ago, I returned from a week-long annual leave, vacation trip with some friends and colleagues to Cold Bay, Alaska. And anybody in the waterfowl world, when we mention Cold Bay, Alaska, one of the first things that will probably come to mind is Izembek Lagoon, and then comes to mind And so that's going to be the topic of our discussion today. And we have joining us remotely, Dr. Mark Lindberg has done a lot of research on this species over the years, much of his career. And Mark, great to have you here. I was with you just last week, but it's good to see you again. Mark Lindberg: Nice to see you, Mike. That was a blast last week. It was a blast. It was a great trip, even for those of us that live in Alaska, that's a very special place to visit. Mike Brasher: I wanted you to talk a little bit about your research on Brandt, and we can just kind of keep this brief. Talk about some of the topics that you covered and how, I guess, how much of your time in Alaska intersected with Brandt. Mark Lindberg: Yeah, so like I said, I first went to Alaska in 1990, the spring of 1990. And I don't know, a week after arriving, I was shipped out to the field site on the Yukon Delta of Alaska to learn the ropes from then a very experienced technician who had been running the Tatako River Field Camp. And quite a shock, right? Left New York, Pennsylvania, Showed up on the Yukon Delta, which is an expansive, flat, coastal plain. And when we showed up in early May, it was white. It was a white golf course that extended forever. Anyways, got in the camp, and my research was focused on site fidelity in general of brand, the behavior of them returning to the same place. year after year, and I looked at that at multiple scales. I looked at it at the colony scale, blackbrant and general nesting colonies, and I was asking, do they return to those colonies year after year? I looked at whether once they returned, did they return to the same nest site, and did they use the same area to raise their broods? The fun part of that for me, well, it was a very interesting question in general, but it allowed me to travel around and visit other colonies to see if birds were moving. We have them marked with tarsal tags that are individually coated, and I traveled around to the western Arctic of Canada, Anderson River Delta specifically, several colonies on the Yukon Delta, to the north slope of Alaska, Colville River Delta. And I looked for a brand over the next four years that had dispersed and asked the question, how much do they move? And so what a great way to get a taste of Alaska. And yeah, that was an excellent project for me. It worked out really well and worked really well with Jim Sedinger, my advisor at the time. And he continues to be very actively involved in black brand management conservation, even in retirement. Mike Brasher: Mark, did you have graduate students that did work on Brandt over the years? Mark Lindberg: No, so when I finished my work on Brandt, I had… Jim continued to supervise the project. He's… I believe he's been supervising that… He supervised that project from 1984 to 2017. I had students work on Emperor Geese, a student work on Emperor Geese on the Yukon Delta, It was only in like 2016 that I started to talk to Jim about his retirement and who was going to take over and I started going out back out to the delta then and then in 2018 I took over leadership of the field site at Tautauk River and I supervised students there and still do but I was in charge of the camp through 2021 and now David Koons is taking over leadership of that project. Mike Brasher: We'll hop right into this one, and I'll get you to talk about, well, the first question I guess I have for you from a personal perspective, and I think it's also a great place to start for this episode, is the common name for this species. You can start out with the scientific name, but I want you to talk about the common names that we often hear for this species. You'll hear it referred to as Brant, Black Brant, Pacific Brant, Pacific Black Brant, I've heard some people use that, Atlantic Brant, there's Brent Geese. So, kind of unpack, unravel all of that nomenclature around this species, if you could. Mark Lindberg: Thanks, Mike. So, as I already mentioned, my work has been almost on Brant has been almost exclusively in the West, and that subspecies that exists in that flyway is Black Brant, Pacific Black Brant, Sea Goose of the North, I've heard it called, because they have almost an exclusive marine habit, and they're one of three species worldwide. They nest in the Yukon Delta and then the Alaska and Western Arctic of Canada as well as the Arctic of Russia, the blackbrant does, and that's Branta bernicola nigricans, that subspecies. The other North American subspecies that's recognized are Atlantic brant, which nest in eastern Arctic Canada and winter on the east coast, notably New Jersey and New York shores and coast, and they're known as Branta bernicola rota, and they're distinguished from the black brant by their belly color. So Atlantic brant have almost a white belly. Black brant, as the name implies, have nearly a black belly. There's a hybrid. It's not officially recognized as a subspecies in the central Canadian Arctic, more to the west. In the Parry Island region is the gray-bellied brant. They don't have a specific subspecies designation. They breed in that region. They look like they're hybrids between Atlantic's and Black's, as the genetic shows, and they tend to winter in the Padilla Bay region of Washington. They do pass through Isenbeck Cold Bay area, as we'll talk about here in a little bit as well, but they tend to winter further north and do the Black brand, which I forgot to mention, used predominantly winter in Baja, California, Mexico, but as I'm sure we'll talk about over the last two decades, it really started to change that distribution. And then just to finish, the world population of brant, the European subspecies Branta burnicola. It is often called the Brent goose, and I hope you don't ask me much about them, because I don't know much about them. But that's the three subspecies, Branta burnicola is the species. Mike Brasher: So when we talk about any type of brant or brent geese, it's the same species, but there are different subspecies and maybe even some subpopulations within those subspecies out there. Is that also kind of the thing that I've read? Like maybe the Western High Arctic, Eastern High Arctic, that may just be more related to some of the breeding populations. Is that right? Mark Lindberg: Yeah, that's the breeding populations. And from a management standpoint, they're not managed differently. From a conservation standpoint, I don't think for this podcast those designations are as important, but they're certainly… In the sciences, we talk about those population… Down to the population level because we're interested in how they are changing or specific challenges they might face on the Yukon Delta versus the Arctic Coastal Plain of Alaska, for example. So that population designation, I think, is… less important probably than the hunter, if you can think of it that way. Mike Brasher: You and I were talking before we started recording, and I was asking about how much work you had done on Atlantic brant versus Pacific brant, and you made the point that most, not just your research, but most of the research in general for brant in North America has been conducted on the Pacific subspecies, Pacific brant, Black brant. And that's not to say we don't know a few things about the Atlantic Brant, but for this podcast, most of what we'll talk about will relate to the Pacific Brant. So, just want to kind of give people a heads up on what to expect there. You did note that there are some key developments through the years for Atlantic Brant that will be important and some differences, some major differences in the ecology of those subspecies that we'll touch on. But for the most part, And largely because a significant volume, significantly more from a volume standpoint of research has been done on the Pacific Brant, that'll be our focus. So, I guess, Mark, let's move on here for those that may not be familiar taxonomically and appearance-wise for this bird. What's the Brant's appearance and who are its close relatives within the waterfowl world? Mark Lindberg: Yeah, good question. So there's second smallest goose in North America. The Ross's goose is the only one that's smaller. They're two and a half to about four pounds, depending on the gender and the time of year. Late summer, they're at their lowest weight after breeding. And then, um, when they stage for the black brand, when they stage for migration, they, they put on almost half again, their weight and get up close to four pounds. They're not much bigger than a mallard, but their appearance is very unique. Black brand, like I said, and Atlantic for the top part are mostly black. They have a very distinct neck ring, white neck ring that is quite subtle, but I think you would agree is pretty beautiful. And then, like I said, the black brand has mostly, well, they have some grayish barring on their side and then the belly on the black brand is black. that on Atlantic Brant is mostly white. Taxonomically, that's a good question about the closest relatives. Well, they're in Branta, so they're related to other geese. I actually don't know off the top of my head the most closely related goose. Mike Brasher: So, I was doing some additional reading on this species earlier today and last night because I was kind of curious about some of these things. I try to come into these conversations with some understanding of background material. Barnacle geese and Canada geese and brant are all kind of in that same, I don't know, clade or whatever would be the proper term. Does that sound about right? Mark Lindberg: That sounds about right. Yeah, that's what I would have guessed, but I must admit I didn't review that off the top of my head. I wasn't sure. So I'm glad you did your homework more than me. Mike Brasher: What about like appearance differences between adults and juveniles or first year birds? A lot of people are going to be familiar with the difference in appearance between first year white fronts, first year snow geese, and their respective adults. How does that pattern play out for Brandt? Mark Lindberg: Yeah, the most distinguishing feature between the juveniles of the year and the adults is the coverts, the feathers on the wing that cover the trailing feathers, the primaries and the secondaries, are white edged in the juveniles and all black in the adults. And that's visible in flight and certainly in hand. And that stays with the bird through its first year of life before it molts that and replaces it thereafter. The juveniles tend not to have quite as much of a white neck ring either, but that's not always the case. And the white coverts are guaranteed that that's going to be visible and useful for aging birds. Mike Brasher: Yeah, and highly visible when the birds are in flight. That's one of the things that I found myself noticing as we were out hunting the birds. And you can see them if they bank with the, and if you got the sun, if they're close enough, then it's very, very easy, like it is with other goose species, to identify the young from the adults. And so, just wanted to point that out. You know, this is a species of goose that is definitely more restricted in its distribution across North America. It's more of an estuarine, a coastal bird, and so as a result of that, there's going to be a larger percentage of our listener base, some of the people that are interested in this podcast, that will not have interacted much or kind of seen Brant compared to, let's say, white fronts or Canada geese or snow geese. I think it's pretty cool in that regard. It's another one of those species that we can introduce people to that they may not have encountered to this point. So, in that regard, one of the things that I want to do is play the call of the brand. This is a single bird. Mark, I don't really remember this being a prominent call that we heard there at Cold Bay, but I don't know how many instances we would have had a single bird, more like flocks of thousands that we had. So here's a, I think this is a call from a flock of brant. It's a pretty interesting call, I found it to be. And then here's another. So a grunty, growly kind of call, and they also do a little bit of a rolling of their call in some respect. And so anyway, that's what they sound like. And we were out there on Isenbeck Lagoon, and we had tens of thousands that were across the water, and I took an audio recording of that on my phone, and it's pretty cool to hear that sound kind of coming across the water there. Mark Lindberg: Yeah, that call is wonderful. Most interesting of the geese, if you ask me, but it's interesting. They talk about how smells bring back memory, but that call for me brings back really fond memories. So it's a neat one. Mike Brasher: Well, let's move along here, Mark. I want to talk about distribution. You've covered this a little bit from a global standpoint. So let's just talk about from the big picture standpoint, where do these birds in North America breed? Where will people find them? Mark Lindberg: Yeah. So again, black and Atlantic are a little, well, they're quite different, but black are a bit unique in that they do nest out of the Arctic and the Yukon Delta. Historically has been the main breeding area for the black brand that's changing slowly but surely but currently it's still the predominant breeding area for black brand. Although that breeding range extends of course in the arctic of alaska western arctic of canada and the arctic of russia eastern russia as well. There was one place that I don't think there's brant nesting there anymore that I really liked on the Sword Peninsula. I was hoping to visit during my PhD. It was Nug-Nug-A-Luck-Tuck. It used to have a small colony of brant, but I never made it there, and I don't think they're there anymore. Mike Brasher: That's too bad. Well, you remembered the name properly, though. Mark Lindberg: Yeah, there you go. The central Arctic of Canada, more Western, I should say, Prairie Islands, again, the gray bellies, which are hybrids between the Atlantic and blacks, and then the Atlantic's predominantly Eastern Arctic of Canada, and to my knowledge, nothing further south of the Arctic. I'm thinking for a moment there, but yeah, I think they're restricted to the Eastern Arctic of Canada and their breeding distribution. Mike Brasher: One of the interesting things that you shared with us last week, Mark, is that for that Pacific population, there's a group of birds or subpopulation that nests along the north slope of Alaska. And then there's a group or colony that breeds there, nests there in the Yukon Delta. And you were telling us that there's a certain affinity of those sort of, how would we say this, maybe different migration timing or different wintering associations between those groups of birds? Do I remember that correctly? Mark Lindberg: Yeah, we're just now starting to tease that out a little bit more. Part of the challenge is that most of the studies have been done on the Yukon Delta. There hasn't been quite as much done on the North Slope, although there's some, and marking birds notably. But yeah, all the world population of blackbrand, including those from Russia, migrate to where we were, Cold Bay, Alaska, Eisenbeck Lagoon specifically. They use some neighboring lagoons as well in the fall. They show up there about the same time from those various breeding areas and they stage there for a month plus before some of them migrate out of there, but fewer and fewer of them leave that area, and some more and more spend the winter at the Izembek. And those that spend the winter seem to be predominantly those breeding in the Arctic, whereas those that still continue to migrate tend to be those breeding on the Yukon Delta. Mike Brasher: Yeah, I found that really interesting and I know we'll come back and touch on that a little bit later on when we talk about migration and wintering and how that's changing and why it's changing, but I just kind of wanted to piece that together a little bit, the distribution of those birds. I guess, are they recognized as sort of separate populations or I guess separate breeding populations, right? Mark Lindberg: Separate breeding populations, but there's still a lot of genetic connection between those, so not to get too much into this now, but Again, I studied fidelity for my PhD work, and two forms of it for their affinity to breeding areas. One is natal phylopatry. Do you return to the area where you were born to subsequently breed? And then breeding fidelity or phylopatry is, do you breed to this area where you previously bred in a previous year, year after year? And about fifty percent this is a rough number of the individuals that about fifty percent of the individuals have show natal fidelity that is they return to the area where they were born to breed or is about ninety five percent thereabouts. of the birds show breeding fidelity. Once you start breeding in an area, you come back to it year after year. But that exchange of genetic exchange among those populations is quite extensive when they're young, because 50% of them move among various colonies. Mike Brasher: Mark, let's talk real quick about the wintering distribution of these birds. And I guess you've already mentioned kind of the staging area there in Isenbeck Lagoon. If there's anything that you want to add about the Atlantic population, Atlantic branch, you can in terms of key staging areas for them. But also let's talk about wintering locations for the black brand and then what we know about Atlantic brand. Mark Lindberg: Okay. Let me start with black just because that's more familiar to me, but again, they all stage at the Western tip of the Alaska peninsula, mostly at Eisenberg lagoon, staying there a month plus putting on a half again, their body weight. Sometimes those adult males are showing up at, Oh, 1200 grams and leaving an 1800 grams. And for good reason, because one of the things they're famous for is They take on a nonstop migration from the Alaska Peninsula to Baja California, some 60 hours of sustained flight, almost 3,000 miles, and very tied to higher elevation wind patterns that they exploit to migrate. Mike Brasher: And Mark, what you mean by that is they time their departure from Isenbeck Lagoon to coincide with favorable wind conditions associated with certain types of atmospheric patterns. They want that strong tailwind kind of given that long distance migration, right? Mark Lindberg: Yeah, exactly. And the other thing I'd add about Brandt is they're built to fly. They're just so unique and geese and so fun to watch in flight and how they work the wind. I try to use the analogy of a sailboat. It's almost like they exploit that wind with those long, narrow wings in a very unique way for geese, particularly. And in the summer, just to add to that, they're the only goose that I'm aware of that's capable of aerial pursuit of avian predators like gulls. I mean, they will take a glaucus gull on and track it in the air and even reach out and bite it to fend it off. So that's pretty fun to watch them. Mike Brasher: Yeah, that was one of the things that I noticed as well. Their wings are very long. They are much more pointed than the wings, pointed kind of from a sense of appearance than what we see in Canada geese, white fronts, snow geese. And that's not unlike some of the differences in wing morphology and wing shape that we see across the entire spectrum of birds. And we've talked about this on a previous episode about how that is The shape of those wings is kind of evolutionarily tuned to some of their foraging strategies and some of the habitats that they occupy in response to their preferred diet. There's probably some feedback onto those things one from the other, but those birds with longer wings, more pointed wings, you typically associate with more open environments, open water environments in the case of Brant. I kind of find myself wondering what it would look like for Brant to land on upland. I'm certain they can do it, but are they a little more awkward than cackling geese and let's say white fronts? Mark Lindberg: No, they tend to be a little longer legged and they're quite capable on land, although they don't spend much time there relative to the other geese. I was just thinking in North America, they're the only goose species that hasn't really started exploiting agricultural subsidies, crops in any real numbers. But during breeding, of course, they're on land and very capable. Mike Brasher: That was one thing that I noted in some of the reading about Atlantic Brant. They have started to exploit some of the turf grasses, and that relates to changes in their food resources on the Atlantic coast. But yeah, Black Brant, Pacific Brant, and certainly have not. I didn't find any reference to that. And so the other thing, we'll finish out one little thing here, then we'll take a break. You talked about the magnificent long distance flight from Isenbeck Lagoon all the way down to Mexico, but there are some, there's some portion of that Black Brant population that stops kind of along the way or that will winter in Washington or else stop in Washington and make their way down to Humboldt and then down to San Diego. Is that, how large of a percentage of the population do we see doing that? Mark Lindberg: I think it's the minority for sure in the fall, um, in the spring, that is the way most of them, uh, work their way back as they sort of jump between spot, uh, spot, maybe a hundred, a couple of hundred miles apart and work their way back in the spring. But in the fall, it's, it's the minority. And, um, you know, we were talking about this a little bit last week, but I'm fascinated by is. How do they communicate that, hey, we're not just flying to the next eelgrass bed today. This is the real deal. We're going 3,000 miles. Or maybe we're going 2,000 or 1,000 even. But how do they, especially the young birds, this is their first time. And that fascinates me. Migration in general fascinates me. But that aspect of it is particularly intriguing. This might be a tangent, but You know, add to that other breeders on the Yukon Delta that are even more amazing in migration, Bartelt Godwits, we talked about a little bit. But they go 8,000 miles nonstop over eight days. And Arctic terns, who have a similar wing structure to bran are going maybe as much as 10,000 miles to the southern hemisphere. So, I mean, how do you make this decision one day, hey, I'm going to fly 3,000 miles nonstop. And, uh, that's amazing to think about. Mike Brasher: It is. And, and the fact that they can navigate these, to those, those destinations, uh, over such a long distance, it, it really is one of the, it continues to be one of the most fascinating aspects of that group of birds from a behavioral standpoint and what they're able to accomplish. Let's pick up with a, the wintering distribution of Atlantic Brand. Where do we find those? And are there any major staging areas like what we see for, for Black Brand? Mark Lindberg: Wintering wise, they're 90% of the population of approximately 150,000 Brant winter on the coast of New Jersey and New York. They extend down to North Carolina at their southern extreme, but most of them are on the northern part of that distribution along the Atlantic coast. Um, staging, I actually don't know that Mike. Mike Brasher: Not enough to talk about it with any confidence. I forget. I forget if it's, if it's during fall or spring, but I know, uh, James Bay, uh, plays a role in the migration of Atlantic brand, but I can't remember if it's coming or going or if it's both actually, it may be. Mark Lindberg: Their migration distance in general is much shorter you know it's it's less than half the distance that the black are migrating so i would i would suspect that the staging areas maybe less dominant and important given that distance but. I'm shooting from the hip a little bit there. Mike Brasher: Mark, I think right now is a good time to talk about one of the more notable things in the ecology of brant and what we've learned over the years and that is how their distributions during winter have changed. I think related to that we'll want to talk about their diet because that plays a key role in some of what we're what we've observed over the years, maybe more for Atlantic Brant with regard to some of the profound changes in their food resources there. So, let's start with that. Brant are incredibly fascinating because of their reliance, heavy, heavy reliance on a very small group of foods. And for Black Brant, it's primarily one species of plant. They've had to expand their diet on the Atlantic coast because of some losses of their traditionally favored food item. But talk about that. What makes Brant so cool from their foraging and their food preferences? Mark Lindberg: Yeah, so through much of the year, except breeding, they rely almost exclusively on eelgrass as their main food resource. And eelgrass is a long, narrow ocean plant that is pretty extensively distributed, but not always very productive in all of its range. And so Brant tend to focus on those areas where it's most productive. But it does appear, as you've mentioned Atlantic, that eelgrass is sensitive to change and is deteriorated in some regions. It appears to be deteriorating in Mexico, probably because of agricultural runoff and sedimentation uh, introduction of pesticides and, um, that are affecting its productivity. And as we talked around a little bit, I, and of the two points I want to emphasize today about black brand, this is one of them. Um, we're seeing black brands starting to respond to that change as well. So 20 years ago, um, the estimates were less than 5% of the population wintered in Alaska. And today, that estimate's close to 40% are thought to winter in Alaska now. And you can debate that a little bit, but we've shown it's very tied to El Nino cycles in the Pacific and ocean temperatures associated with that, which are likely affecting eelgrass as well. And like I said, 40% of the world population of black bran are starting to… Are now wintering in Alaska. Mike Brasher: I want to explore that in a little detail because I was describing to my wife about some of these things. She worked for Ducks Unlimited back in the day and has an interest in waterfowl and wetlands, and I was explaining some of these things to her, and she asked me a few questions. I'm like, I don't really know how that would have played out. So, historically, back at the time when you said that only 5% of the black branch population overwintered in Alaska, there at Izembek Lagoon. What was unfolding? What were conditions like there during winter? Did it freeze? Did Izembek Lagoon freeze back then and they simply weren't able to stay there? Or was it a situation where the food resources in Mexico were so much better? Have we seen a change in food resources one way or another? Or is it just sort of the result of some different strategies employed by individual brand, and then we're not seeing as dire consequences these days for those birds that are wintering in Isenbeck Lagoon. And just through time, we've seen those birds succeed and represent a larger portion of the population. How's all that playing out? I asked you about a dozen questions in that right there. So, let me go back and say, historically, would Isenbeck Lagoon ever freeze? Mark Lindberg: I think it froze more extensively than it does today. I don't know that it ever froze up. But interestingly, I was telling you earlier about an article that's recently come out that included an interview with Jeff Wasley, who I said had spent 20 years there. And he was recalling, I think it was last year, Eisenbeck froze as much as it ever had in the time that he's been there. and there were some 70,000 birds wintering there. I suspect this was probably in December, November, this occurred. And they displaced for a while, but then returned to the lagoon and apparently did fine. So even if it did freeze historically, the birds might have had alternatives and more exposed habitats or other areas that were not freezing. So I don't know that that alone is the explanation. And we don't know is the answer, by the way, why more wintering there. I don't think it's a single reason. The other dimension that has intrigued me is that we've shown a real decline in the condition of goslings that are produced both on the Yukon Delta and the North Slope of Alaska. Habitat conditions for foraging during brood-rearing or braiding, and they, I wonder if they're not capable of the flight. And so maybe the decision is made to not go, or if they go, they don't make it. And the tradition is not passed on. It seems a little too rapid a change to think that it's translating through generations in that manner yet. So again, I don't think it's the sole reason, but it's one that intrigues me. So Bran are leaving the Yukon Delta at much lower mass than those from the North Slope. And they're in pretty rough shape when they show up at Cold Bay. And we've shown, and the other really good data set, I think, is over the last 20 years, first-year survival of those goslings has declined at an alarming rate. So up around 60% or so 20 years ago for both goslings produced on the North Slope and Yukon Delta, and today That's down around 20% for both populations. Wow. And so you wonder how that's translating into things like migration traditions and, you know, not a much smaller fraction of the goslings produced that year are making that migration. And who knows how that's translating through generations. Mike Brasher: You mentioned that there seems to be a relationship to between the number of Brandt wintering in Mexico and El Nino events or El Nino years. Can you explain that a little bit? What's El Nino is the warming is a… pattern of the warming of Pacific waters near the equator. How does that affect, do we know how that affects the resources there in Mexico and how it might be less beneficial or how it might be adverse, create adverse conditions for Brant? Mark Lindberg: Yeah, I think the other way to think about it is that it creates more favorable conditions in the north. I see. So it may not just be the adverse effect. I mean, they might be able to show up in Isenbeck and and identify or react to cues that they're experiencing, maybe even ocean temperature, production of eelgrass in those years might be changing, and just say, well, is it really worth it? Why not just stay here? And so I'm not so sure it's them anticipating the conditions that might exist in Mexico as much as what they're experiencing when they show up at Cold Bay. Mike Brasher: Okay. Well, that's interesting. I really hadn't looked into it that much, but that makes sense, I guess. What else from kind of a historical change perspective there at Isenbeck or what we're seeing there in Mexico? Anything that we've kind of left out that's of importance here? Mark Lindberg: Maybe from a harvest standpoint. I mean, traditionally the harvest was almost exclusively in Mexico and that is changing with more and more birds being harvested. in Colton Bay, Izembek specifically, and harvest rates there have gone from about 1% to 4% over the last couple of decades. And Mexico is, it's got some really traditional users, but it's becoming less and less important from a harvest standpoint than it used to be. Mike Brasher: Let's talk about Atlantic Brant for just a minute in terms of historical changes in their food base. Also, like Black Brant, their primary diet item, their primary food historically was eelgrass. But talk about some of the key events that occurred back through the years and how that has affected where we see or what we see as the diet of Atlantic Brant these days. Mark Lindberg: Yeah, so there's two major events in the history of Atlantic Brant that I'm familiar with. The 1930s, which I'm sure isn't very well documented, but there was some type of disease that spread through the eelgrass beds. I don't know if that was temperature related or not, but it was very descriptive back then, but apparently Atlantic Brant numbers just absolutely plummeted. And then again in 1970s, which was better documented, change in eelgrass productivity, I don't remember the exact reasons, but estimates of number of Atlantic brant went from 200,000 to 40,000 in a couple years. And they're a pretty captive audience, right? There's not extensive eelgrass beds that are productive enough to sustain them. So mortality rates had to have been insanely high for that to occur. On average, you're surviving at about 80% per year. And if you do some quick math, their numbers had to have been less than 50% annual survival during that period to have that kind of decline. They're pretty vulnerable to those kind of changes. And it appears the changes in Mexico for black bran are occurring slowly. But now you potentially have most of the population in almost a single lagoon system in Alaska. I mean, the vulnerability of that species. And unlike Atlantic's, there's no opportunity if you're wintering in Alaska to go feed on golf courses or on terrestrial plants. which might be available at Atlantic Brand Wintering in New Jersey. Mike Brasher: Yeah, I did read that the Atlantic Brant have adapted to the decline of those eelgrass grass beds by exploiting some golf courses and other turf grass areas. And I'm pretty sure that that's the feeding, primary feeding habit of Brent geese in Europe as well. I seem to recall that they're one of those upland, have become one of those upland grazing species. You have Wigeon as well in certain parts of Europe. have adapted to those upland landscapes and are foraging on that green grass. Incidentally, that might be the reason why there's a significant difference in the flavor profile, you might say, the table worthiness of black bran and Atlantic bran. I've heard… That's always the thing that people will… One of the first things people will say when I tell them that I've returned from Coal Bay, Alaska and we harvested a few bran, they're like, have you eaten the branch yet? And it's like, no, not yet. I actually have though the past two nights, I did have Brant and it is absolutely wonderful. People will tell you that black Brant on the Pacific coast, on the Pacific Brant are, by all accounts, I've not heard anyone say anything different, are the best tasting waterfowl species, at least in North America. And Atlantic Brant are pretty far on the other end of that spectrum, that gradient in terms of how they are as table fare. And you have to believe it's related to diet, correct? Mark Lindberg: Oh, definitely. Yeah, and I'm not going to dispute with anything about that in terms of table fare. I mean, black brent are amazing. Yeah, their taste is incredible. Yeah, and that is actually just to reinforce that one thing I do know about the European brent, the brent geese and the widgeon, their degradation of habitat has caused them to use terrestrial food resources more in winter than they used to. Again, I wonder how much of that will be available to Pacific brand or Black brand if Mexico resources decline, or worse yet, Atlantic resources decline. Seem like a pretty vulnerable population from that standpoint. Mike Brasher: Let's talk about spring migration if you think that's an appropriate way to go. Mark Lindberg: Yeah, that's fine. We're kind of on that topic, and I mentioned already that Blacks… It's kind of weird. I call them Black brands. I call the Atlantic Atlantic so of course but you you tend to be specific but hopefully everyone's with us when I say black I mean Pacific black brand so. Anyways, they trickle north in the spring, and in addition to eelgrass, there is some evidence that they're probably using some herring roe too when it enters their diet. And I don't know that they would taste as good in the spring. I haven't had the opportunity. but it would fatten you up pretty quickly. And they just make their way north in a, like I said, sort of hopping point to point, including some staging areas up the west coast of Alaska, even before they make landfall on their breeding areas. And there was one study I'll mention relative to this student that I didn't advise, but I interacted with and still do today, who worked on the physiology of both wintering in Cold Bay, Izembek, and in Mexico, and they did that by collecting birds and looking at their physiological condition. Interestingly, those birds by the spring had basically converged on a very similar condition. So you had these birds in Cold Bay that had to deal with a winter that was pretty challenging, You know, their, their, uh, condition declined because of that, but the birds that flew to Mexico had the cost of migration. But once they arrived there, they had better weather of course, and reasonable resources. And then as they worked their way North, they were hitting good resources coming up coast of British Columbia and so forth. Um, but by the time they rejoined each other, this is like 20 years ago, um, in the spring, their condition was very similar. So I thought that was a pretty fascinating. That study was done, like I said, almost 20 years ago now, and I think that would be a fascinating study to redo, and I volunteer to go out and help them do that. I bet you would as well. Mike Brasher: I'm sure I would. Let me talk to Steve about that. Let's see if I can work that into my schedule. Mark Lindberg: Yeah, no, but I thought that was an interesting part from a migration standpoint, the strategy of staying or migrating, at least in those years, resulted in almost the same outcome. There's something else that has been looked into a little bit, not as extensively as we hope, but there's something called cross-seasonal effect, and that is how are the decisions you make in terms of winter translate into breeding areas, and there is some evidence that it does translate, but not at a level that's huge, it's not a big effect. Mike Brasher: Yeah, those are two dramatic differences, two dramatically distinct migration wintering strategies. One is let's just stay in Alaska and the other is let's fly down to Mexico. And just as you've talked about this issue of cross-seasonal effect and how do different migration strategies translate into differences in reproductive success is a very important topic, and it's getting a lot of attention among some of the duck species out there right now. And it's just fascinating that apparently there's not much of a difference, at least historically, 20 years ago there wasn't. But yeah, I agree with you, looking at that again would certainly be fascinating. Mark Lindberg: So, you know, we were talking about population strategy, basically. Are you part of the population of winters in Alaska or are you part of the population of winters in Mexico? And I think by and large, that is what's going on. It's a population level strategy. Yukon birds tend to go to Baja, North Slope birds tend to stay in Alaska. But I got involved in some research, it was 10 years ago now, and it was on individual heterogeneity and basically individual strategies. And it's a really fancy word. that or a phrase that means there's some birds in the population that are better at what they do than others. And some of this came out of my PhD way back in the 1990s. There was something we documented that was really strange to me at the time, that there was members of the Pacific brand population that we characterized as permanent non-breeding. So, to our knowledge, they never successfully bred, to the point where, year after year, they were identifiable on molding areas for failed and non-breeding brand. And at Teshepuk Lake on the North Slope of Alaska, these birds, year after year after year, would show up there, and someone actually did work on the fidelity of these birds. We looked at it a little bit differently and just asked, over the life of the bird, are there individuals in the population that do really well, and then those that don't do as well? And roughly, we called them good and bad birds. And sure enough, there's really strong signatures that you see in Pacific Brant on the Yukon Delta, at least, for individual heterogeneity or individual variation in quality relative to survival and reproduction. And there's these really productive birds that if you harvest them, it has much more effect on the population dynamics than harvesting, quote unquote, bad bird. And that really intrigues me from a harvest standpoint. You know for waterfowl brand for sure there's no external characteristics there's not anything you can look at the bird flying by and say shoot that one don't shoot that one I mean you know roughly speaking if you could shoot a juvie over adult that's one way of thinking about it you you would be better off from a population standpoint shooting the juvie or for that matter shooting the male or the female if you could identify them what you can somewhat in in flight but but then within females. There's this range of quality of these individuals, and that just intrigues me to no end. There's these birds that we could look at their individual histories, and they're just absolute super birds from a production standpoint. And we got into some population modeling in it, but you can actually show mathematically, this sounds like hocus pocus, but it's not. You could show that you can increase harvest, and if you could target quote-unquote bad birds or low-quality birds, you could actually have the population increase in abundance, because by doing so, you've increased the proportion of the population that is made up of good birds. Mike Brasher: Yeah, it makes total sense to me. You consider it a… If you were able to do it, you're effectively, kind of quote, high-grading the population to a larger percentage of those more productive birds. No, I get it. Mark Lindberg: Yeah, and I think there's some opportunities to exploit it. I mean, you need really good data to be able to do this, really refined data. But if you think of Brant and Pacific Brant, again, back to these permanent non-breeders, If that's true, they're probably low-quality birds. You could go target harvest to them, maybe at Teshepuk Lake and have minimal effect on the population rather than shooting the breeding birds from the colonies we spoke of already. So the opportunity intrigues me. One of the largest migrations now, waterfowl are migrating resident Canada geese in the Atlantic, right? those likely tend to be lower quality individuals. May not be breeding, may not be successfully breeding. If you could target them, you could shoot a lot of them and have more less of an effect on the population than if you went and shot breeding birds. Mike Brasher: Yeah, that's an interesting way of thinking about it. And individual differences in reproductive rates or survival rates and then behaviors is, it's a growing field. I saw a social media post a few days ago by Dr. Mike Chamberlain, who is a turkey ecologist, researcher, I think Mike is at the University of Georgia still, and with individually marked birds, they're able to look at the… I think they were looking at movements and distances traveled and how there are different birds that do different things. And then in the context that he was looking at it, there's the potential for those different behaviors to expose them to greater or lesser risk of being harvested. And so, the idea that All birds or all animals are the same and they just represent an average animal. I think we're certainly getting to the point where we can throw that notion out the window, but then how do we quantify those individual differences and are there management implications for those differences is really where it sounds like we're going next in a number of ways, which is, yeah, very fascinating. Mark Lindberg: Yeah, I find it completely fascinating. And there's got to be a genetic basis for it. That quality has to be heritable to be of importance in the population. And the more obvious examples are in the mammal world, where we're shooting full-curl rams only. Well, arguably, those are high-quality individuals by definition. So the harvest of sheep, doll sheep, thinking of those in Alaska at least, is exclusively of high-quality individuals. And so, just through math, you're reducing the proportion of high-quality individuals in the population. And you might even be selecting for changes in horn length. We've seen this in moose. The number of brow tines used to be more focused on in terms of harvest regulations, and they've shown in populations that you basically eliminate the genetics for individuals with more than three brow tines. because you're focusing harvest there. So I think there's examples that this is translating out more challenging in a bird world, more challenging to identify quality by external characteristics. But I think we need to start thinking about this more and more because it could be an opening to increase harvest while reducing impacts. Mike Brasher: Thanks for that, Mark. This is probably a good place for us to take a break. We're about halfway through the conversation, and so we'll do that right now, and then we'll continue this discussion here in just a few moments. Welcome back, everyone. We're here with Dr. Mark Lindberg, talking about BRANT. When we left off, we had just concluded with a discussion about individual heterogeneity and how fascinating that was, even not just within waterfowl, but all a lot of different species of wildlife. We had touched a little bit on the, I guess, some of the differences between Pacific Brant and Atlantic Brant and some of their migration tendencies, and I think that's what stimulated this conversation about individual heterogeneity, differences in how individual birds will approach certain aspects of breeding or migration. I think it was also at that time that we, when we took that break, we said we were gonna And to go back and study up a little bit on Atlantic Brand, because in the previous episode, much of our discussion was on Pacific Brand, that being where you've studied most of your career. And, uh, so yeah, I guess that's where I wanted to start out is, I know you did have some, some time to look back at some information on Atlantic Brand. Is there anything that we need to clean up or supplement the previous episode regarding Atlantic Brand, uh, from, from last time? Mark Lindberg: Yeah, thanks for the opportunity to do so. I had forgotten about their migration patterns, and I think it's worth mentioning. The Pacific we covered in quite a bit of detail, and as I told you, I was always very impressed with that nonstop migration they make from Cold Bay, Alaska Peninsula, most of them, all the way to Baja, California, and Mexico. almost 3,000 miles. And for some reason, I wasn't remembering the Atlantic branch migration patterns, and I had in my mind geographically that it wasn't as far. But just recapping that now, in the fall, they leave their main breeding areas, which is south of Baffin Island in the area known as the Fox Basin in the eastern Canadian Arctic. And they fly to James Bay at the southern tip of Hudson Bay, where they spend upwards of almost two months staging. But the interesting part to me of reviewing that again is that that initial movement when they're at depleted body condition in the late summer, the lowest weight, is 1,000 miles. So unlike Pacific brand that aren't moving nearly as far to their fall staging area, those Atlantic brand have to make a fairly substantial movement to James Bay to stage and build reserves for the next thousand miles or so that they'll migrate to the Atlantic coast, again, focused on New Jersey and New York, as most of them spend the winter. But then in the fall, they have less opportunity to trickle back north, or I'm sorry, in the spring. they have less opportunity to trickle back north and do Pacific brand. Again, they have to make a fairly substantial jump from their final spring staging areas on Atlantic coast to James Bay, which they return to, again, about 1,000 miles, spending again about a month there, and then jumping up to largely the Fox Basin area of the Eastern Canadian Arctic. I hadn't thought about that much until you asked the question, and it would be fascinating to have a comparison of the physiological strategies that they employ for those quite a different migration demands that they have. And if you're going to do one nonstop 3000 mile flight, you probably would use a different strategy than two 1000 mile legs. And, um, that would be interesting to see that comparison, which I don't think has been done. Mike Brasher: So anything else to add there, Mark? Mark Lindberg: I don't think so. Other than maybe just a note, um, you know, abandoning a strategy that's so risky. is, well, risky, right? These birds leave an area and are flying thousands of miles in anticipation of finding suitable habitat for them to survive. And it actually goes to some of the vulnerabilities in migratory birds, because changes that are occurring in areas where they're not currently at could have huge effects on positive and negative, for that matter, if we start thinking about snow geese from a positive standpoint. But imagine there's some catastrophic oil spill or some type of contamination that's occurring on staging or winter areas, and you leave an area anticipating you're going to find good stuff, and you don't. I just want to mention that because migratory birds and migratory traditions require an extra level of vigilance as we manage them in their habitats to think about and putting in a plug in for you guys. I think you think with that viewpoint that, boy, there's some birds coming from a long way off that are going to rely on the habitats that we're conserving. And we got to do a good job of that because if they show up and it's not well done, they're in trouble. Mike Brasher: Mark, the other thing that we'll probably add to the discussion from part one of this series relates to the diet of Atlantic bran. We talked about how they're beginning to shift due to some of the historical changes and decline of their eelgrass habitats. They've successfully adapted and changed their diet to include some upland grasses from golf courses or other other type of turfy areas. The other thing that they will consume and has been found in a fair percentage of the diet of Atlantic brant that have been examined are things such as widgeongrass. They do still eat eelgrass where they can find it, but they also supplement that with widgeongrass and then a fair amount of algae. I forget exactly what kind of algae it is, but that's become a pretty common part of their diet on the Atlantic coast. showing some flexibility there over the years in what they're able to consume, but still almost exclusively a vegetarian species. And so, just want to make sure we added that in our discussion. The other thing that I'll note right now is that as I've heard you talk here a few times already in this episode, there's your son's parakeet, I think, in the background is chiming in to help out with the conversation. So, if people hear the bird chirping in the background, just know that's what that is. I do find that it's… It responds whenever you start talking there mark which is pretty interesting. Mark Lindberg: Yeah i'm surprised you're picking up pizza back in the corner trying to catch him but unsuccessfully it's all good. I just one question i had you read about the diet that you might know better than me is. So these birds moving on to golf courses, I haven't thought about this for a long time, but is there more and more regulation about application of pesticides and insecticides to golf courses or fertilizers that are being considered given the increased reliance on that food? Mike Brasher: I'm really not sure. I don't have a read on that at all. That would be a conversation for someone that I guess is more familiar with the habits and tendencies of Branton that may have thought about that in terms of their consumption of pesticides, herbicides that would have been applied to golf courses. And I don't even know how common foraging on golf courses per se are. I just, I know I've seen that referenced, uh, along with foraging and other sort of turfy grassy areas. So don't have a good read on that. It's a good question though. Mark Lindberg: Yeah. Something I don't think about much from Alaska. Mike Brasher: Yeah, for sure. Mark, let's move along to sort of the breeding ecology of this species. And I think here there'll be some similarities between the Atlantic Brant, Pacific Brant. So just kind of walk us through that. I don't remember if we talked about it on the previous episode about lifelong pair bonds for this species and anything else regarding mating system. And then we can just kind of move into the nesting season for the birds. Mark Lindberg: Yeah, like all geese, they're monogamous, but there's exceptions to that, and they divorce and they have extramarital affairs. And yeah, there's surprising data from some species where we've done genetics about how many males are actually involved genetically in the production of a clutch. You see a pair of emperor geese is the work I'm thinking of. And you think, wow, they're a really strong pair, and surely it's the only male contributing, but genetics show two or three males might have contributed to that clutch. So yes, they are long-term monogamous, though. And one aspect of that, or sort of side aspect of it, is that waterfowl are exceptions among birds. There's a few other groups, but they exhibit what's called female biased phylopatry, and that the female returns to the site that she chooses, which is typically the site she was born at or previously bred at, and the male is just along for the ride. So Yukon Delta colony, you'll get males from all over the place. They're paired with females that are predominantly from those breeding colonies. Mike Brasher: Mark, we had a conversation with Dr. Jayvon Bank recently where we did a species profile on greater white-fronted geese, and in that conversation we began to talk about the different strategies that waterfowl employ with regard to where they get their nutrients that they need for egg production and nesting. We started talking a bit about the the capital versus income breeders, and that was in reference to kind of where white-fronted geese fall on that gradient. What do we know about Brant in terms of where they are on that gradient? Do they bring with them all of the nutrients that they need to create, to produce a clutch of eggs and incubate? Or do they supplement that with some foraging once they get to the nesting grounds? Talk to us about that a little bit. Mark Lindberg: Yeah, by and large, they bring what they need with them. And what you define as the nesting ground gets a little bit in the semantics, but they are staging on areas close to the terrestrial habitats they'll use and taking on nutrients. there, so within 50 miles possibly of where they'll ultimately make landfall. But the reason for that is there's a real premium on nesting as early as you can. There's good data showing that nest initiation date is highly correlated with ultimate, well, nest success, but then production and growth of your goslings too, because those goslings have to… The timing of hatch has to be such those goslings have access to high quality forage, and those birds that nest earlier tend to have goslings that have access to highest quality forage. Boy, that was a mouthful, but hopefully you got the point. So we've shown a real strong relationship between timing of nesting and ultimate reproductive success. Mike Brasher: And that's a pattern that's similar across… all waterfowl species of which I'm aware of, the earlier they get there, if we're talking about prairie nesting ducks even, the earlier they get there, the more opportunities they have to re-nest. And then there's also some reasons why the earlier they get there, in some cases have been documented that ducklings survive at higher rates because related to kind of typical deterioration of wetland conditions as you get farther into summer. So there's always this urge to for waterfowl to get there as quick as possible and initiate their nesting as quick as possible. We spoke about that in the context of kind of what's happening with waterfowl as they're down here on the wintering grounds and preparing to get back north in the spring. There's this urge to get there as quick as possible. The same thing applies to Brant. That's what you were talking about there, right? Mark Lindberg: Yeah, for sure. There is a bit of a caveat to that in that in the really detailed data sets we have, it seems like the earliest nesting birds, you don't want to be first. It seems like those birds are subject to hibernation. You can imagine there's these communities of predators, arctic foxes in the case of Brant that might have been waiting for brant to return and are low on food. And so some of those earliest nesters don't do quite as well, and or they might be subject to storms or weather patterns that aren't affecting their nest success. And some of the most refined data sets, including that on Pacific branch, show that the earliest, earliest nesting birds, those first couple of days, don't do quite as well as those that delay a couple of days and then start nesting. Mike Brasher: That's interesting. What about nest site selection? Are brant colonial nesters? Where do they fall within that view of things? Talk about their nest site and their nesting tendencies. Mark Lindberg: Yeah, so they are classified as colonial nesting, and with few exceptions, they tend to follow that. There are some dispersed nesting birds on islands, but that's not common and that's low in numbers. When I worked as a graduate student on Pacific brand, they were kind of a peak at the colony I worked at. And nearest neighbor distances, the closest distance between nests was down to a meter, three feet roughly. And there was one… We have these long term nest plots, we search that they're 50 meter radius circles, that this one in particular was in the highest density nesting area. And half of that plot area was in a lake, so only half of it was available for nesting, and that plot had 95 nests on it at its peak. Oh my goodness. And you can imagine what that sounds like, what that looks like. The challenge for me was we would go in and web tag the goslings hatching from those nests. Some of you are familiar with those tags we put in the webbing of the goslings as they're coming out of the egg. that helps us identify them later when we catch them during banding. The trick was to get in that colony and web tag goslings without them leaving the nest early, because sometimes if you disturb them, they'll leave the nest. So you got 95 nests in a 50-meter radius circle, and you're trying to systematically work around that to to mark them, and it was quite the challenge. I basically could never stand up, so I crawled nest to nest, and the hatches were highly synchronized. Most of those nests would have hatched in about a week-long period, and yeah, it was fascinating. So 90 times… Well, let's round up so I can do easy math, but 90 times… 100 times a clutch of four or five, you're looking at four to 500 goslings, emerging from eggs, hatching from eggs in a one-week period, and the goal was to mark them all. So basically for a week, I crawled around on my hands and knees in a colony, putting web tags on goslings. Mike Brasher: And the crawling around on your knees was to minimize the disturbance? Mark Lindberg: Yeah, so if the female… The hatching of those goslings is fairly synchronized, but sometimes you'll run into a nest where there's three that have hatched and one that is still pipping, trying to get out of the egg. And if she's disturbed too much, she might just take off with three of those and leave that pipping egg behind. So you need to try to do everything you can to minimize that. And we actually had an observation tower near that particular part of the colony. So I would work for a couple hours, web tag, and then I'd crawl up in that tower and make myself disappear, take a rest. eat some food, and yeah, I'm reminiscing here back in the day. That plot currently, because of the declines in nest density on that particular colony, only has about 10 or 15 nests now. So the current techs have it pretty easy. The colony has shifted its distribution, but it's declined by more than half in terms of number of birds too. So they don't have quite that intensive high-density area. Boy, that was a real tangent relative to your question there. Colonial nesting and density sometimes can be as high as a meter apart. Mike Brasher: That's fine. I like tangents. Kind of the personal stories and the visuals that you can paint for us, I think are pretty cool. We'll move on to sort of the nest itself and the clutch of eggs. If people haven't gathered already, they do nest on the ground. Anything unique about their nest site that would differentiate them from any other Arctic nesting goose that nested in the tundra up there, nest on the ground? Mark Lindberg: Nothing too unique other than their willingness to nest so early and put eggs on the ground about one per day for four or five days, even in slightly flooded conditions. They'll put them in water. Wow. And they're pretty much just a scrape at that point, nothing more, no down. Those eggs are quite viable even at They can't freeze, but even at relatively cold temperatures, because the female doesn't start incubating them until about day two or three with any constancy. So they're just sitting out there on the ground, somewhat exposed, and they slowly add nest material and then down and it becomes quite a nice insulated nest by the time they're done. Here's a little aside to this though. One of the areas they're nesting now is subject to occasional flood tides, and sometimes those tides are high enough coastal areas that they'll destroy nests, but we've had several nests that have simply been lifted by the tide and floated some distance, maybe five meters or so, 10 feet or so, and then just redeposited And the female just continues incubating them and they hatch. So we've had several instances of that. Where we come back, we have markers at the nest site so we can find them again. And when we come back and there's no nest there, there's marker but no nest. We got to do a little detective work to figure out where the nest is now. Mike Brasher: Yeah, that's really interesting. And that kind of brings up another point about some of the risk to nest. How often do nests get flooded out? Those flood tides, are they a… a common source of kind of nest abandonment or nest failure? And are those incidents becoming more frequent and more severe as we see things change in the Arctic? Mark Lindberg: Yes. Fortunately, it seems like the frequency from bird nesting standpoint is higher. The increased frequency is higher in the fall than in the spring. and summer for that matter. But yeah, as you may know, we had one of the more severe flood tides hit the Yukon Delta region this fall, and those are getting more frequent. But that one was incredibly severe, moving water as far as 20 miles inland. Mind you, that's not much of an elevational gradient, but it probably put five, six feet of water over the bank at the colony proper. The birds had already left when it hit, but if that had been during nesting, that would have been a complete loss. We've lost, I don't know, 5% to 10% of the nest at Tatacoak to flood tides in a season at a high end. It's not that common during nesting to get those kind of flood tides. Mike Brasher: And clutch size average of about four to five, something in that range, right? Yeah, four to five eggs is pretty typical. No re-nesting, no opportunity for that. Same as with all other Arctic nesting geese. Mark Lindberg: We've never documented re-nesting, but we've documented a couple cases of what we call continuation clutches, where the bird loses part of its clutch and then continues that clutch at another site, or in some cases, dumps it in what we call a dump nest, where you might have 20 or 30 eggs in a single nest that a female is obviously not just her own, but other birds are dumping their eggs in. Mike Brasher: And then the incubation period for Brant, where does it fall? Mark Lindberg: 24 day-ish, 25 days. Like most waterfowl, they don't start incubating until they've laid an egg or two. And then the real constancy of warming the eggs doesn't start until later in the clutch. And that's another tangent that's fascinating, but how is it that eggs that are incubated a different amount of time, you know, in a nine-egg mallard clutch, say, there might be five to six days difference in incubation time, but they all hatch on the same day. So it's precocial young, but that's a… Maybe not a tangent you want to put down. Mike Brasher: That's a topic for another episode for sure. Yeah. Okay. So female only incubation, yet the male stays nearby the nest to provide some vigilance. Anything else? Did I get that right? Mark Lindberg: Yeah, that's true. Females only incubate, although it's fascinating. So we have marked individuals and we know their gender. A third, maybe a little bit more of the colony, has markers on their legs, so we know them individually. And you can't easily tell their gender just from appearance, so we've sexed and aged them when we marked them, so we know that. And one of the surprises occasionally is that they're very individual in terms of their tenacity to the nest. And as you approach, sometimes you'll see females slipping off way in advance, and other ones you have to literally lift off the nest to see their eggs gently. But we have the occasional one where there's a bird sitting on a nest as we approach, but it seems a little odd. And then when we get there, we realize it's the male that is more protective than the female. He's not incubating, but he'll hover over the nest and you get there and you can tell it's a male because he doesn't have a brood patch. He hasn't removed feathers from his belly to allow him to have skin-to-egg contact and effectively incubate. But you'll have the occasional male that do that, and there's one notable male that would occasionally land on people's heads as they were visiting the nest, the female would move off. And we have a famous, infamous photo of Jim Sedinger with a branch sitting on his head. Um, well, he inspected the nest and no one was harmed. Mike Brasher: Yeah. I'm really tempted to ask you, and I guess I will by saying this, if there's any, uh, documented relationship between that male aggression and, uh, and, and success of, of the nest. Mark Lindberg: Boy, that was a conversation of many, uh, nights, um, in the weather ports of our camp. Um, the, uh, the quote came about, it's not the size of the, dog in the fight, it's the size of the fight in the dog, and there's quite a bit of bickering that goes on in terms of establishing a nest site, and the male has a very prominent role in that, and we wondered who those males were that got the optimal sites, and optimal being in the middle of the colony, sheltered from… Buffered from predation, and maybe a high elevation site that doesn't flood as easily, and And we don't know the answer, but it was a fun conversation to have at night and camp and we were cooking dinner or something. Mike Brasher: Yeah, I appreciate these stories and the first-hand perspective that you can bring to this. It gives a level of detail that I can't whenever we're just doing ordinary kind of high-level discussion of these species profiles. Talk with us a little bit about that. What do the goslings eat? The male and female are going to be providing that bi-perennial care because of these long-term perennially monogamous pair bonds. What are the goslings eating? And then talk to us about the thing that's begun to emerge and that's sort of a topic of exciting research right now. Mark Lindberg: There's a simple part to this story and then a more complicated part. So the goslings hatch, they actually have a yolk sac that'll allow them to survive for a day or two, but they fairly quickly move on to their preferred sites for foraging. which in the coastal area can be quite long distances. We're kind of intrigued by how they move, and we anticipate or expect that they use tidal movements to be able to move upwards of 20 miles eventually, maybe even a little further. But they're trying to forage on new gross sedge, by and large, and its most digestible form is just a small or a low growth form that the goslings could pick at. We call them grazing lawns and they look like putting greens, was probably the best analogy. And those lawns are maintained by grazing from adult geese. And if it's not grazed, again, a good analogy is your hedges, if it's not trimmed, those sedges will grow to a higher growth form that's less digestible and usable by small goslings, as you can imagine. And one of the complicated parts of this story is that it appears… Well, it doesn't appear, it's numbers declining in some of these colonies, and that feedback and that maintenance of those grazing lawns is not being sustained. And it appears that goslings have less and less desirable forage areas, particularly on the Yukon Delta, because numbers of adults have declined and there isn't as much grazing going on before they hatch, and as a result, there's not as much forage there. The reasons for the decline are really debated, but in areas like Comparable on the north slope of Alaska in the Arctic Coastal Plain, where numbers of bran are increasing, those grazing lawns appear to be maintained much better. And goslings are fledging from northern part of Alaska much heavier than are those from the Yukon Delta, because they have better forage during brood rearing. And it's not apparent how the… If those trends are going to continue or not. And one of the driving questions on the Yukon Delta right now for continued research is, can brand and maybe other species revert those larger growth forms of those sedges back to the desirable growth forms. And there's a lot of changes going on that we don't understand those dynamics very well yet. And this isn't a tangent, but just for an example, when I was leading that project as a student in the early 1990s, God, that just seems like a long time ago. I used to use the phrase from Jimmy Buffett's song, he went to Paris, you know, 20 more years slip away and that doesn't apply anymore because now it's 30 years and so I need a different song. Anyways, when I was leading that project on the Tatako River Brant colony, it was sort of a treat to find the nesting cackling goose. They were very uncommon, and they were distributed largely at the southern end of the colony. And now that colony is pretty much interspersed with them, and they're about 50% cacklers and 50% brant nesting there, roughly. And maybe those cacklers, which also graze on some of those same plants, will help maintain those lawns Mike Brasher: Yeah, it certainly is an illustration, another illustration of how nature is complex. It's not linear. There are a lot of interacting factors that are controlling what is good or not good for waterfowl and all sorts of other critters that are in the natural world. And that's why sometimes when people ask us a question, like what's going on with this, we don't necessarily have the right answer right now. We can identify certain parts of what we think are going on is contributing to it, but it takes some time, it takes some creative thought on what to study and how to study it, and this is a perfect example. And thinking about grazing intensity by geese on on Arctic landscapes and how that affects the nutritional quality of the grasses that grow up in response to that level of grazing is not dissimilar from thinking about grazing rates or stocking rates and grazing intensity for cattle production, right? There's an optimal rate, optimal stocking rate, and intensity of grazing to maintain optimal nutrition quality in those grasses, it's exactly the same way of thinking about it, right? Mark Lindberg: Oh, definitely. Yeah. And the other aspect that we haven't done a very good job of understanding is how these communities of birds and mammals, for that matter, interact in these environments to affect those habitats and their welfare. Mike Brasher: So Mark, we'll move on now, and let's talk about how long it takes the goslings to fledge. What are we looking at there? Mark Lindberg: Yeah, so in the Yukon Delta, well, goslings everywhere take about 45 to 50 days to fledge, just to give you a rough idea of what that might look like. on the Yukon Delta, that hatching occurs about mid-June. Of interest to a lot of people is in about mid-July, we capture the goslings and their adults and their parents, and we round them up in nets because they're all flightless at that point. The goslings have not reached the stage of fledging yet, and the adults are molting their wing feathers, so the entire family is flightless and allows us to capture them. So at about 30 days, roughly, we capture them, place bands on them, and take measurements. And then, again, about another 20 days, they'll fledge. So sometime in August, for Yukon Delta brand goslings, they're obtaining flight. Mike Brasher: So Mark, I think that pretty much completes the annual cycle for the birds now that we've got the young on the wing. And so I guess the next step will be to move on to harvest. And we've talked a little about harvest rates on the previous episode, but not a whole lot about total harvest and things of that nature, because this is a time in their annual cycle when the birds start migrating to their fall staging areas and where they start encountering hunters. But before we do that, anything that we have overlooked of note on the on their breeding ecology? I don't believe so. No, I think we've pretty much covered it. And I think we've done a good job covering that fall migration as well and the significance of those staging areas. So, let's do move on and then talk about harvest. There's at least two different types of harvest. There's subsistence harvest and then there's also the sport harvest. What do we know about those different types of harvest? Maybe if you want to, what do we know about harvest rate and then total harvest? Mark Lindberg: Yeah, so I think people probably can relate to total harvest more than a rate, because the rate requires you to know how many individuals are actually in the population, and that's disputed. So, roughly speaking, harvest, total harvest, sport harvest is about 5,000 brand. and that's between Alaska and Mexico by and large, with some harvest occurring in the Pacific Coast as well between those two points, but not nearly as much. Those are the two main areas. Subsistence harvest is really a wild card, and one that could be of concern, but current estimates of subsistence harvest are between 10,000 and 30,000 grant. classified as Pacific branch. So another way of saying that is we don't know what subsistence harvest is. And a threefold difference in harvest in any given year, which could be as much as a six times the harvest of sport harvest, is something we need to learn more about. And we just don't have a good way of surveying that. It's not well described and there isn't a tradition of reporting information on harvest by subsistence users, that's just not part of the culture. So that's a big black box in some ways in terms of that harvest. We do know, and this incorporates both harvest, sport and subsistence harvest, we do know that survival of adults has been relatively stable at around 80 to 85% annually over the last couple of decades, slight decline maybe. and that annual survival of first-year birds or juveniles has declined fairly substantially during that time. That may or may not be related to harvest and likely isn't the predominant contributing factor, and we think the reduced habitat conditions on both breeding and wintering areas are a bigger contributor to reduced gosling survival than it is harvest. but that gives you a rough idea of what we're looking at for harvest. Again, harvest rates appear to have gone up in recent decades from about one to four percent, but again, that relates to the total population size of Pacific bran, I'm quoting here, and that numbers fairly disputed now. Survey techniques have changed quite a bit over the last decade. Notably, these winter surveys have been eliminated, and as we've already talked about, BRANT are shifting their winter distribution, so that makes it even more difficult for specifics And that number is debated right now. Between 150,000 to 200,000 is what you'll typically hear. There are some new photographic surveys, video-based surveys going on. They were going on while we were at Cold Bay. And those that are doing them have high hopes, but we'll see. We still don't know if that's going to play out. So it's a little hard to relate harvest rates and even, for that matter, total harvest to The effects on total population size which is a little bit difficult to know Atlantic brand or about a hundred and fifty thousand as well by the way I don't know as much about harvest over there though. Mike Brasher: You know, Mark, I was actually looking at that as you were talking. Harvest of Atlantic Brant from 1999 to 2008 averaged to 26,000 birds, which that's a substantially greater number of harvest than for Pacific Brant based on the numbers that we have, which that kind of surprised me. About 30% of that occurred in New Jersey, 30% in New York, 20% in Virginia, and then the remaining 7% in Maryland, maybe a few other places. But yeah, those are the states where that harvest occurs in the Atlantic. Pacific Brant, as you talked about, certainly Alaska, Mexico, California is another kind of big source of the Pacific Brant harvest there. I don't have anything here in front of me regarding harvest rates or survival rates for Atlantic brand. I don't know if you have any of that handy either. Mark Lindberg: I don't. I don't think there's nearly as good information. I mean, that Pacific brand harvest rate and survival rate estimates was based on a huge data set recently published in 2017. Some work I was involved with and getting that type of data is pretty difficult. That was very extensive data that was quite detailed. Mike Brasher: Mark, one thing of note here to kind of wrap up a survival discussion, survival harvest discussion, something that we incorporated on the previous episode with Jayvon Bank, where we talked about greater white-fronted geese with longevity record for brant. It's 22 years and seven months for an Atlantic brant and 27 years and six months for a Pacific brant. So you get some of those longer lived species, the uh, among the geese and yeah, you can get something pretty easily in the 2025. I think Jay said for greater white fronted geese, the longevity record is over 30 years. I can't remember if it was 32 or 36 years, but it's maybe it's 38 years, but it's getting on up there. It's pretty incredible. Some of these birds can live a long, long time. Yeah, it is. Mark Lindberg: And you know, it's been a really, um, what's the word? A really rewarding experience to get to know some of these individuals that have lived in the long time. Some ones we've marked. They come back to a similar area year after year, and you get to interact with them and get to know them. And you think about it, some of these birds, so 10 years into their life, may have migrated some 60,000 miles, double that if they've lived 20 years, and you have the privilege of studying them. I mean, it is a privilege, and you really feel obliged to be careful with what you're doing and try to be as respectful of an individual that's putting itself out there as much as it is. Mike Brasher: Absolutely. You said the word that was in my mind, and that is respect. The more we know about these birds, the more that we see what they have to deal with, and the more we see the amazing feats that they can complete, whether we're talking about a 3,000-mile migration or a lifespan of 25 to 30 years. Respect is what these birds deserve, and that's also kind of behind a lot of the conservation efforts that we do within Ducks Unlimited and our other partner organizations and partner agencies. Brant kind of being where they are and in terms of breeding, staging, wintering, the type of habitats that they occupy, it's not as easy to do intensive management for them as we can for some dabbling duck species and some diving duck species, maybe to a lesser extent. But we nevertheless have to stay in tune with the threats that their habitats are facing and how changing environmental conditions, changing climatic conditions are affecting their ecology, their ability to survive and reproduce. And so that kind of takes us to the final section here where we want to talk about concerns, conservation concerns and priorities or research concerns. What can you tell us about that? When you look across the landscape for Brant, where are our greatest information needs, our greatest uncertainties or conservation concerns? Mark Lindberg: I think all those meet, I suppose, in habitat, broadly speaking, our changes in our ocean habitats. is occurring at alarming rates, and that has effects not just on the ocean waters themselves and the plants they're in, like the eelgrass, but then on the near shore waters or land areas as well. As salinity levels changes, as flood tide frequency increases, I think this is the next frontier for brand in general. On the East Coast, for Atlantic's, development activities as well are something you have to consider in terms of how that's affecting your near shore land areas and associated habitats. Less of a factor for Brant that tend to straddle the major development in California, but on the West Coast in general. But for Atlantic's, I think development activities would be as well. I'm just absolutely astounded that we can make the changes in ocean environments that we have. We're affecting entire ocean environments, and that's a little mind-boggling to think about. Not only that we as humans have had that effect, but more to me is, how do we change that? That storm that occurred Well, the storm in Florida this year and the one on the coast of the Yukon Delta were both the result… Ian in Florida, the other one didn't have a name, but their intensity, their severity was a part of increased ocean temperatures. Not just that they formed, but how much rain they deposited as they moved across those land masses. And yeah, that's pretty… frightening at one level, but also, I don't know, inspiring or challenging, maybe is the word, that we need to try to do something about this. So I think for Brandt, that's the big conservation challenge. Mike Brasher: And Mark, you know, people, when we have these conversations, sometimes people will, and we talk about how things are changing, people will say, well, what's What's going to happen? What's going to be the outcome of all of this? And of course we don't have that answer because it depends on at least a couple of things. One of which is it depends on whether we're able to do anything to kind of reduce the rate of environmental change that may be occurring or that is occurring in a lot of places. The other is that it will depend on is the ability of the birds to adapt at a similar rate at which the changes are occurring. I think we're starting to see across the wildlife community that there are some species that are going to be capable of doing that for a number of reasons that partly we don't fully understand yet. There are other species that are perhaps more specialized and that will be a bit more constrained, we think, in their ability to adapt at the same rate at which their environment is changing. We don't entirely know right now, and unfortunately that puts us in a situation of having to not entirely wait and see, but learn as we go. And it emphasizes the importance of continuing to invest in science and the research behind the scientific information that we rely on. to keep an eye on what the populations are doing and how they're responding to changing environments, changing conditions, intervene and control what we can control where we can. And so that's, it's, you don't like to feel helpless, but sometimes you, sometimes that's where you find yourself, I think, at least it does for me. Do you, is that taking sort of a defeatist approach? Mark Lindberg: Or what are your thoughts there? I mean, I feel both of those. sides of the emotion right sometimes i just want to throw in the towel because it seems so overwhelming and most of the time i just want to continue to try to tackle it and take it on as i think most in our profession do i mean i'm transitioning to a new phase of how i contribute but it's no less inspiring to try to do something to help help the situation you know the challenge i think in our profession not to get into the weeds too much but the details is that We're facing problems now that require us to collaborate at levels that we never had to before. If you were just managing a single wetland complex, even a refuge, you didn't really need to work with anybody. Maybe just that refuge staff was capable of it now. But when you start thinking about Managing ocean environments you know there's no one group that's gonna put their arms around that and you know more now more than ever you know we need to stop building silos in our profession and within our profession. is not just people employed in the profession, it includes hunters and conservation-minded people. I mean, we need to work together collectively to address these problems that are bigger than any one group. And so, I think that's exciting to think about how we can do that. And we're gonna need to do it, I think, to address these problems. Mike Brasher: Mark, I think that's a great place to wrap up this episode. This has been a great conversation, a detailed conversation about one of the most intriguing species of waterfowl that we have in North America because some of their uniquenesses, their long distance migrations, their reliance on a a narrow suite of foods and heavy reliance on a few key staging areas and changes that we've seen in where those birds are wintering and staging, and maybe not necessarily staging, but wintering. They're incredibly unique for a number of reasons, and it's been a pleasure to talk with you about them, and I hope our listeners enjoy the conversation as much as I have. Mark Lindberg: Thanks for having me. It was really fun to talk about this species in this topic. Mike Brasher: A very special thanks to our guest on today's episode, Dr. Mark Lindberg, retired wildlife professor from the University of Alaska Fairbanks. We greatly appreciate his time and expertise. As always, we thank our producer, Chris Isaac, for the wonderful job that he does with these episodes and getting them out to you. And then we thank you, the listener, for your time and for spending it with us and for your support and commitment to wetlands and waterfowl conservation.