Latest / Ducks Unlimited Podcast / RELOADED EP234 - Waterfowl Harvest Management Series, Part 15: Beyond Mallards in Modern AHM

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RELOADED EP234 - Waterfowl Harvest Management Series, Part 15: Beyond Mallards in Modern AHM · Ducks Unlimited Podcast

• 0:03
  VO: Welcome to the Ducks Unlimited Podcast RELOADED, where we bring you the best of our past episodes. Whether you're a seasoned waterfowler or curious about conservation, this series is for you. Over the years, we've had incredible guests and discussions about everything from wetland conservation to the latest waterfowl research and hunting strategies. In RELOADED, we're revisiting those conversations to keep the passion alive and the mission strong. So sit back, relax, and enjoy this reload.
• 0:35
  Mike Brasher: Today, we're gonna be continuing our discussion on the history of harvest management here in North America, and we're sort of entering the final phase of this discussion for this current season of the Ducks Unlimited Podcast. I'm very happy on this episode to welcome in a guest that's gonna help us talk about one of the things that's already been introduced, adaptive harvest management. We had a four part discussion with doctor Jim Nichols on sort of the history, emergence of adaptive harvest management, and the implementation of it. But the guest that's joining us today is gonna take us sort of into modern times over the past twenty five or so years of adaptive harvest management and help us understand where we are today and maybe give us a look into the future on where we're going with adaptive harvest management and other aspects of waterfowl harvest. Our guest today is doctor Scott Boomer, wildlife biologist with the branch of assessment and decision support for the US Fish and Wildlife Services Division of Migratory Bird Management.
• 1:29
  Welcome to the podcast, Scott.
• 1:31
  Scott Boomer: Thanks, Mike. It's great to be here today.
• 1:32
  Mike Brasher: We're gonna start out with you giving our listeners, giving us a brief history of your personal and professional bio. So let's just get started with that, Scott, if you don't mind.
• 1:40
  Scott Boomer: I'm originally from Upstate New York, I grew up in a small town right on Lake Ontario. I then was able to go to university at Cornell University and was fortunate enough to continue there for my graduate studies. I got a MS and a PhD from that same institution, and then I did one year's worth of postdoc work, actually in fisheries, and then I was fortunate enough to get this current position that I'm in with the Fish and Wildlife Service. As you said, I'm a wildlife biologist with the branch of assessment and decision support within the Division of Migratory Bird Management within the US Fish and Wildlife Service. I was hired primarily to provide technical support for the services adaptive harvest management program, and currently I coordinate the program and serve as the coordinator of the harvest management working group.
• 2:33
  Mike Brasher: Scott, I was mentioning here offline before we started recording that your title of wildlife biologist is very unassuming relative to the duties that I know that you're responsible for. So I just want wanna point that out, and I think people will see as we get through this conversation, the level of of intellect that you bring to Harvest Management is vastly impressive, and I thank you for taking the time out of your busy schedule to share some of this with us, and it is a treat to be able to piece together some of these different guests relative to this topic. We've just completed a series with doctor Jimbo Robinson talking about the point system, and now we're going to continue with you, and I know all of these are your colleagues, so it's kind of neat in that regard as well. So as I mentioned, Jim Jim Jim Nichols we have two Jims here that I'm talking about. I have to realize that.
• 3:23
  Jim Nichols provided us with an extensive history on adaptive harvest management. So now I wanna just transition to to a more modern perspective, and that's where you come in. And I guess just picking up from where Jim Nichols left off and his reflection on experiences with adaptive harvest management, I want to get yours. After twenty five years of implementation of adaptive harvest management, What do you how do you view what we have learned about itself, the decision process involved in it, duck populations, duck hunters? I mean, just big picture.
• 4:00
  What's your view reflection on adaptive harvest management and how it has helped us as a harvest management community?
• 4:07
  Scott Boomer: Sure. Well, to just reconnect with the transition of Jim Nichols' podcast, I was fortunate enough to listen to those this week, and he did a great job of covering the history and the, really, the evolution of the Adaptive Harvest Manager approach that we use today. I've been lucky to work with Jim and folks like Ken Williams and Fred Johnson, who really were innovators in developing the Waterfowl Harvest Management approach and utilizing, you know, the concepts of adaptive management. And so, you know, like you mentioned, we've been operational for twenty five years now, and in general, over this timeframe, we've been very fortunate to experience good habitat conditions. I think Jim mentioned this in the previous podcast.
• 4:58
  And in general, most waterfowl populations are doing very well. In terms of what we've learned formally through the process, you know, Jim had talked about the evolution of model weights and how we have some support for the additive harvest mortality hypothesis and really strong support for the weak density dependent hypothesis. Throughout that framework, we've been liberal. And in the face of twenty plus years of liberal regulations, harvest rates on adult male mallards have averaged about ten percent, which is a little bit surprising given that I think the initial projections for what we'd achieved with liberal seasons was right around 12 to 15%. So that was something that's interesting.
• 5:48
  And I think more generally, you know, the waterfall harvest managed community has really embraced the principles of and that's resulted in a lot less contentiousness in our decision making. We don't really experience the same types of arguments at the various regulatory meetings that we did in the past, and I think that's attributed to this buy in to this approach that we're using to inform regulatory decisions.
• 6:15
  Mike Brasher: Scott, you mentioned that the average harvest rate for adult male mallards is somewhere around 10%. I might be catching you off guard with this question, but it popped in my head. Do you know offhand? And if you don't, that's fine. I realize this is gonna be a pretty specific question.
• 6:31
  Do you know offhand if we have seen any trend in that harvest rate through time?
• 6:35
  Scott Boomer: Within the last ten or fifteen years, we haven't. It's been hovering right around 10%. And and in fact, I just redid an assessment to actually estimate reporting rates over time, that same timeframe. And in order to estimate those reporting rates, we have to estimate harvest rates as well. And so they're the best estimates, and a lot of that data is based on reward banding data, so it's some of the best we have to estimate harvest rates.
• 7:04
  And, yeah, we have not seen a lot of variation over that time frame.
• 7:08
  Mike Brasher: Interesting. I just wanted to ask that because it, again, just kind of popped in my head. Let's move on now to talk about objectives. This was a big part of our conversation with Jim Nichols, and he emphasized the importance of having clearly stated objectives before we go forward with any type of decision making or decision making process. Where do we stand with current objectives?
• 7:33
  Are there any are there any efforts to revisit those? This is a pretty open ended question here because maybe you could take it a number of different directions. But where do we stand with objectives, and are those under revision? Is there any thought of that of that occurring, or have they been revised here in recent years?
• 7:52
  Scott Boomer: Sure. Yeah. Absolutely. I can give you an update. So the the Mid Continent Mallard framework just underwent complete revision of that decision framework.
• 8:05
  It was a, it spanned a couple of years and involved a technical working group from both the Mississippi and Central Flyway and members of the Harvest Management Community. And so, you know, we went through what's called a double loop learning process with, I think Jim mentioned this in a previous podcast, where we step outside of the iterative phase and consider other types of issues that might be relevant to, you know, maybe reevaluating the current framework. And it involves reconsidering objectives, the types of regulatory alternatives that we would consider in our decision making, the models that we use. It was a complete revamping, if you will, of that framework. And we spent a lot of time on harvest management objectives.
• 8:57
  As Jim mentioned, you know, they sort of determine really where you go with regards to the modeling framework, but also with regards to the, you know, the development of the decision strategy. And the original objective for Mid Continent Mayer at was to maximize long term cumulative harvest, but that was subject to a constraint where we would devalue population size, subsequent population sizes, if they were less than the we would devalue harvest, I should say, if the subsequent population size was expected to be less than the North American Waterfowl Management Plan goal. And this was a conservation type of objective that was formulated in the objective function. And what we've learned through the double loop process, as well as, you know, during the operational phase, is that we would be, if we continue to use that constraint in our objective function, that we would, we may experience situations where we would forego harvest opportunity during conditions that weren't conducive to population sizes greater than that goal. And so we had a lot of deliberations within the working group, and really, you know, I think the harvest managed community was reluctant to continue that, to continue to apply that constraint as we revised that framework.
• 10:31
  And so, in effect, we have removed that constraint from the objective function, but that doesn't necessarily mean that we're removing a conservation level objective. Because we're maximizing harvest over the long time horizon, that necessitates carrying a population through to maximize that harvest. So, there's an inherent conservation objective within that harvest management objective.
• 11:00
  Mike Brasher: Scott, if I remember some of those discussions and papers and reports related to that correctly, that that constraint, that NAWAMP constraint basically, what you're saying, if I can kinda translate this to a a layperson explanation, is that that constraint might have, in some circumstances, caused us to be more conservative, moved us away from a liberal regulation without much benefit in the long term of of actually, you know, helping to sustain waterfowl populations. Right? In other words, being more liberal during those years when we were getting closer to that Neuwat and Goal wouldn't necessarily been detrimental to the population long term and perhaps would not have been justified in pulling back on regulations. Is that is that a fair way of translating that?
• 11:46
  Scott Boomer: Yeah. That's accurate. I think you're spot on.
• 11:49
  Mike Brasher: And then another part of that discussion also was some debate about, well, what was the intent of the NAWAMP goal anyway, or what what was the thinking behind the role that harvest should play in our achievement of that NAWAMP objective anyway, or the NAWAMP population goal? And I think we we kinda the the community settled on harvest is an important part of the overall waterfowl management enterprise, but it we really want to ensure that we're achieving that neowamp goal primarily through the provision of of adequate habitat, and it would need harvest to be kind of commensurate with with what the population is allowing at any given time. Is that am I right there too?
• 12:28
  Scott Boomer: Yes. Yeah. Absolutely.
• 12:31
  Mike Brasher: That was my attempt to translate it. I don't know if I succeeded. Anyway, I just wanted to take a stab at at that. So interesting conversation. And so that constraint has been officially removed now.
• 12:44
  Is that what you're saying? Yes. Yep. I wanna move on now to any other kind of current changes or changes that may be coming to here in the future. I've spoken with a few other people, and they've referenced maybe some tweaks to what to how we're dealing with the different model sets.
• 13:00
  And we don't have to get too technical here, but just for some information, any other significant adjustments to that might be coming?
• 13:09
  Scott Boomer: Yes. We have the additional twenty five years of information, so we're gonna use that to update, you know, the relationships in the current models that we use to predict population change for Meconic Mallards. And we're actually going to be using some new analytical methods to take advantage of that information. The baseline recruitment relationships and survival models are not really gonna change that much. However, the way we estimate them will.
• 13:43
  And we're hopeful that this new estimation framework really provides a more efficient use of that information going forward, particularly in the face of some of the large scale system changes that we are observing or experiencing now. In addition, we've been able to use the information for US ponds in our recruitment model. So now we'll be predicting recruitment as a function of not just Canadian ponds, but total ponds that we count during the the May annual survey.
• 14:14
  Mike Brasher: I didn't realize that, Scott. That's I am learning a lot on this episode. That's good. I hope our listeners are too, because we we spoke with Jim Nichols about that, and this is where the I'm gonna ask you this kind of question as I frame up part of our discussion with Jim Nichols. We talked about this matrix that was an out an output of the, well, the stochastic dynamic programming, the, you know, the the model, and and that matrix, that table has two axes.
• 14:41
  One is mallard breeding population size. The other at the time was Canadian ponds. Are you is it right to conclude that now that table is going to include total pawn count, or is this gonna be embedded somewhere else? Does the matrix stay the same? It's just some of the modeling changes.
• 14:57
  What are we dealing with here?
• 14:58
  Scott Boomer: Absolutely. That that matrix will, you know, include total pawns now.
• 15:03
  Mike Brasher: Yep. Okay. That was a question that I oftentimes heard people would would look at that table and say, well, why aren't we including US ponds in that? And I think the answer that I heard most often through the years was that, well, we have a longer record for Canadian ponds, and and our our modeling has shown us that that relationship is does a better job predicting. But I guess now with additional years and maybe different techniques, we're able to include The US ponds in that.
• 15:30
  So that's that's exciting to hear. Thank you for for updating us there.
• 15:41
  VO: Stay tuned to the Ducks Unlimited Podcast sponsored by Purina Pro Plan and Bird Dog Whiskey after these messages.
• 15:58
  Mike Brasher: Scott, these changes that we're talking about and many others do not happen unilaterally. There, you even mentioned that one of your responsibilities is to I think you said you're the chair of the Harvest Management Working Group. So I wanna talk about that a little bit to let people know, just give them an idea of the the type of of technical work that goes goes on or the and and the people that are involved in it. So speak a bit about that, giving a nod to your partners on the Harvest Management Working Group, what it is you're responsible for, and kinda how that that group is structured.
• 16:31
  Scott Boomer: Yeah. So, you know, going back to what Jim Nichols described, Fred Johnson, was really the champion of the program at the time of its inception, recognized that this endeavor required a working group, is composed of technical representatives from the state fly from the states that are representing the flyway councils, and then biologists and other researchers from the fish and wildlife service, from across the service's migratory bird offices, which included the four flyweight reps. And Fred recognized that, you know, this group would have sort of oversight on the technical developments of And so, you know, currently, the Harvest Management Working Group serves as the technical arm for the Flyway Councils and the Federal Service Regulations Committee. They're responsible for the development and implementation of and all of the changes and different evolution of the different components of as we practice it today. The working group considers a lot of technical issues regarding modeling and estimation and different forms of decision analyses in support of the regulatory process.
• 17:52
  Last December, we just had our thirty second meeting, so it's a long established group. The meeting itself is a formal, you know, regulated meeting within the regulatory process. And we're able to have representatives from state and federal entities within that through memorandums of understanding within the flyways and the service to meet and deliberate on those issues associated with the federal regulatory process. It sort of serves as the kicking off point for the, what we call the regulation cycle, where we meet and deliberate on any of the pressing issues for the upcoming regulation cycle and review analyses and results from the previous REG cycle. So it's a very important group to meet with and has a pretty large impact on how we go through the regulatory process.
• 18:52
  Mike Brasher: Yeah. And the work of that committee is not trivial at all, and highly technical work that's conducted collectively through that through different members of the committee at the federal and state level, and I don't know that I've ever attended one of those meetings. I've certainly heard reports about it, and so, yeah, just wanted to give people an idea of some of the participation that occurs there, and that there is this group out there that deliberates regularly on many of the technical aspects of waterfowl harvest management. I want to move now to more of a discussion, sort of, I guess you could say, the evolution of adaptive harvest management. It was originally constructed around the Midcontinent population of mallards, but now we have adaptive harvest management for western mallards, eastern mallards, black ducks, and now pintails.
• 19:41
  I don't know if we have it for any other species, I'll get you to answer that, but also kind of bigger picture, how do we move to those how do we get to those different applications of at the species or population level? What does that look like? It's not like we just flip a switch and say, oh, yeah. Well, let's we're gonna do for redheads, or we're gonna do for ring neck ducks. Are there any other species for which we have frameworks right now?
• 20:07
  And then kind of how does that, how does the expansion to different species evolve?
• 20:12
  Scott Boomer: Yeah, that's a good question. We do have another stock for which we use an framework, and that's ScoP. We think we implemented that back in 2010 or maybe 2008. But the the quick answer is that as the decisions become more important, and in fact, result in some give and take regarding, you know, what's the appropriate direction, the harvest managed community sort of steps back and say, Well, can we use the same framework or the same types of methodology in structuring a decision that we use for MidCon and Mallard? So, you know, originally, as you mentioned, all four flyways were being informed by the Mid Con and Mallard framework based on the breeding population information from the traditional survey area.
• 21:06
  And that was a useful starting point with the expectation that, you know, Mid Continent Mallards would serve as a good surrogate for other stocks. But the Pacific Flyway and the Atlantic Flyway were concerned that if the Prairies went dry, that it might not be appropriate for their regulations to be tied to some of the dynamics that were occurring with the Mid Continent stock. And as a result, you know, we have since developed formal frameworks for Atlantic flyaway and Pacific flyaway based on more regional waterfall stocks that are consistent with the birds that they encounter in their flyaways. Similar things have happened with black ducks where we have ongoing deliberations about the appropriate harvest regulation for that stock, and it was actually an international agreement between Canada and The US to develop a formal framework to structure the regulatory decisions for that stock. We've since done that for Pintels and SCOP as well.
• 22:02
  I would add that it's, as we continue to add these decision frameworks that use principles, it requires a fair amount of work throughout the annual cycle to update those frameworks and then actually inform decisions. And it also adds a sort of layer of complexity in in thinking about how we knit together all those independent strategies that are all tied to overall frameworks driven by Mid Con and Western Mallard, and the multi stock framework that the Atlantic Flyway is currently using. So things are getting complicated very fast as we add these add these decision frameworks.
• 22:45
  Mike Brasher: Related to that, Scott, we have these other species for which we don't have formal adaptive harvest management frameworks. How would you describe the the harvest regulation process for them? And are there species there for which we would like to do and we would like to develop an adaptive harvest management framework, but we just don't have the data? I guess I'm just trying to figure out what's the progression of things and what limits our ability to develop for some of these other species for which we might think it would be useful.
• 23:16
  Scott Boomer: Yeah, that's a good question. There's no absolutely, it's true that the development of frameworks require a certain set of elements that, you know, we must have. We need clearly stated objectives. We need regulatory alternatives, a limited set of regulatory alternatives. And then we need the ability to sort of predict how the population is going to respond to regulatory change, as well as any environmental changes that might drive those dynamics.
• 23:47
  And so, you you raise the question, well, what about other stocks that we don't have formal strategies? For example, CamusBak is a good one. These strategies we tend to refer to as prescribed. Are, regulations are determined by a set of thresholds that have been negotiated within the flyways and the flyway councils and the service regulations committee. Some would claim that they, you know, that the frameworks are in a better position to provide guidance in that as much as we're taking into account the internal dynamics and really what the optimization procedures that Jim Nichols talked about is doing is establishing the biological thresholds that come out when you do all of the analyses inherent in that optimization to determine what the right regulation is for each combination of population sizes you might encounter in the spring.
• 24:48
  That's a pretty deep into the weeds response to your question. And, you know, I think you can see that the more you wanna structure that process, the the information demands and the resources require
• 25:05
  Mike Brasher: related to some of these other species that fall within the the total conventional bag limits, you might say, let's say, blue winged teal, green winged teal, widget, gadwall, shovelers, ring necked ducks, where you could shoot six, let's say, if we're talking about the Mississippi Flyway with which I'm most familiar, what would be a trigger that would say, hey, we need to think about a species specific harvest strategy for for this one? Is it simply is it fair to say that one of the key determinants there would be to look at the population status of that bird? And if starts showing some concern, then that provides a trigger for some thought in regard to species specific strategies?
• 25:49
  Scott Boomer: Yeah. Absolutely. Historically, it's always been sort of the declining abundance status of some stocks that that that creates a flag, and then there's more formal in-depth analyses of the available data that might suggest maybe demographically there's some issues going on that we might wanna consider when, you know, crafting regulations for that for those stocks.
• 26:10
  Mike Brasher: You know, kinda related to that, Scott, is is debate. I mean, there's you, of all people, know there's still debate on some of the the harvest effects on population dynamics. These vary a little bit among species depending on sort of life history of of different species. But it's it's common that people will ask, well, why can't we shoot more of this species where our current bag limit is one, and bag limit for this other population, this other species is six, but the population size of that one is very close to the other one. So it seems maybe, I don't know if the answer here is simple or not, but what all goes into evaluating and coming up with an answer related to this question of why can't we shoot more of this species than the other, and maybe this might relate to some of maybe it's a philosophical way of thinking about harvest management for the different agencies, or some of maybe legislatively mandated roles of different agencies, but can you speak to that a little bit?
• 27:20
  What what goes into into the the question of answering the question, why can't we shoot more of this species?
• 27:28
  Scott Boomer: I agree. At face value, it might it might seem like a straightforward question. And, you know, as you've discussed in your previous podcasts, when we address those types of questions, we, you know, we usually have to account for different forms of uncertainty. And in fact, you know, the original framework was developed in response to disagreements about which model would be used to answer that very question. Jim Nichols pointed out, you know, depending upon the relationship between harvest mortality and annual survival, the answers you get when evaluating harvest strategies based on those two models may be very different.
• 28:10
  And so, you know, as a result, we rely on these types of methods that Jim described in your previous podcast. The framework was actually developed in response to some of these contentious types of answers to that question that you posed. I think, you know, one of the most significant outcomes of as we practice it today is it provides managers an opportunity to disagree about what they think is the most important factor affecting waterfowl, but everyone has sort of agreed to a process to resolve some of those issues and account for that uncertainty while we make the decision. In general, you know, the waterfowl harvest managed community relies on what we call a structured decision making approach to developing answers to those questions. We typically rely on the most available information that we have to model the system.
• 29:07
  We do the best job that we can to be able to predict what we think the response is going to be to a particular regulation. And then we derive sustainable harvest policies while accounting for the uncertainty that we care about. I would add that in addition to this technical work, we spend a lot of time trying to develop objectives for harvest management. And so, you know, when someone states that they would like to harvest more, from a decision making standpoint, we kind of need a more specific measurable objective that describes, you know, really what we value from the harvest process. And so, you know, the service has trust responsibilities under the Migratory Bird Treaty Act, so in these deliberations about objectives, we'll typically mandate that a conservation objective is included in these deliberations.
• 29:58
  Mike Brasher: Scott, how much of the challenge of expanding harvest opportunities, harvest regulations, more liberalizing regulations, let's let's just say, how much of that is challenged by simply a lack of current data that would be sufficient to to defend or measure the effect of of a given proposed regulation or the the lack of either the lack of the data or the lack of capacity to collect the data. And this kinda gets to a resource availability question. How much of that factors into what can or can't be done with regard to all of these great ideas that sometimes come up with regard to different harvest alternatives?
• 30:45
  Scott Boomer: Yeah, that's a good question. I don't have an immediate, you know, answer, but I can comment on the idea about information and resources. And yeah, I think as a general rule, when we're asked to address questions about fine tuning of regulations, we then have to go back through the available information and make a determination whether or not we can formulate a reliable response or answer to some of those questions. And what we found over time is that as we get finer and finer scaled types of questions, the realized benefit in terms of additional opportunity isn't necessarily consistent with the costs of collecting the information required to determine if it is, you know, is possible, as well as the operational costs of maintaining those decision frameworks moving forward. So there's a cost benefit trade off there, if you will, when we have to deliberate on those types of questions.
• 31:57
  Mike Brasher: That's not not unlike some of the comments that we heard from Jim Nichols in the way he spoke about that, and as well as Ken and Dale, even in the early days, whenever we came up with new creative harvest opportunities or harvest ideas, ultimately it came down to, hey, well, that sounds great, but we need to evaluate those, and yeah, the the cost benefit aspect of that kind of came through in those conversations as well. So it's it's good to see that that kind of scientific foundation of behind our harvest regulations certainly continues, and if anything, it has it has strengthened through the years. Scott, I think this is gonna wrap us up here on the first episode. We have a few more questions that we want to talk with you about, some that I think our listeners are going to find really interesting related to some sex specific restrictions. We're going to talk about the role of harvest management, maybe from a, you know, kind of practical application, what's it designed to do, and then we're gonna talk about pintails a little bit as well here on the next episode.
• 32:53
  So if you're willing to come back and join us, Scott, we'd love to have you.
• 32:57
  Scott Boomer: That sounds great.
• 32:59
  Mike Brasher: A very special thanks to our guest on today's episode, doctor Scott Boomer, wildlife biologist with the branch and decision support for the US Fish and Wildlife Service division of migratory bird management. We thank him for his time and and joining us here and sharing his expertise. As always, we thank Clay Barrett, our producer, for the great work he does on this podcast. And to you, the listener, we thank you for joining us, and we thank you for your support and commitment to wetlands and waterfowl conservation.
• 33:23
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