Subsistence Harvest and Indigenous Knowledge in Alaska

Liliana Naves

Linked paper: Shorebird subsistence harvest and indigenous knowledge in Alaska: Informing harvest management and engaging users in shorebird conservation by L.C. Naves, J.M. Keating, T.L. Tibbitts, and D.R. Ruthrauff, The Condor: Ornithological Applications.

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Sharing a meal of wild foods with the James family at the community of Platinum, after an indigenous knowledge interview. Photo by Lili Naves, ADF&G Division of Subsistence.

Many shorebirds migrate across continents and oceans, relying on key areas to rest, eat, and refuel. Habitat loss, climate change, and other factors are affecting these birds at their breeding, migration, and wintering grounds. Numbers of long-distance migrating shorebirds that breed in North America are down by about 50% since the mid-1970s.

Biologists and social scientists joined forces in this interdisciplinary study to quantify shorebird harvest and document indigenous knowledge in Alaska. We wanted to learn about the importance of shorebirds as food and cultural resources, what Yup’ik people know about shorebirds, and how they could join in conservation efforts. We worked within the Harvest Assessment Program of the Alaska Migratory Bird Co-Management Council.

Twelve million shorebirds converge in Alaska every summer to breed, then migrate to winter in the Americas, the Pacific, and Asia. The Yukon-Kuskokwim delta in western Alaska provides critical habitat and food for these shorebirds. The delta is also the homeland of the indigenous Yup’ik people. For thousands of years, Yup’ik people have shared this vast wetland with shorebirds. Shorebirds represent only 1% of the subsistence bird harvest in Alaska, but this harvest includes species of conservation concern, in particular the Bar-tailed Godwit. These birds’ population size and adult survival have been declining, and some annual harvest estimates seemed high.

We generated Alaska-wide harvest estimates using a large dataset (775 community-years!) including surveys conducted between 1990 and 2015. The total harvest was about 2,800 shorebirds per year. Godwits were about 1,100 birds per year, and based on species distribution, these were all most likely Bar-tailed Godwits. The egg harvest was about 4,700 eggs per year.

The indigenous knowledge research for this study focused on the Yup’ik culture of the Yukon-Kuskokwim Delta. Working with tribal councils, we interviewed 80 respondents in 5 communities in 2017. We asked about shorebird ethnotaxonomy (how local people name birds and categorize species), importance for subsistence, place names, ecology, and concerns. Traditional knowledge is based on observation and experience accumulated over generations by people living in close contact with nature. We learned that shorebirds are known mostly by specialists. Yup’ik people name shorebirds in their Native language, so we worked with a translator. We learned 24 Yup’ik shorebird names, 7 of which were more widely known among our respondents. Most names are multi-species categories. Some names are onomatopoeic. For instance, the Yup’ik name for Wilson’s Snipe is Kukukuaq, after the sound made during their distinctive winnow display. Place names may tell about sites important for birds: Tevatevaaq Bay is a shallow, protected bay that indeed looks like a gathering place for the Tevatevaaq (Bar-tailed Godwit).

Shorebirds and their eggs are not primary food sources, but are harvested in times of scarcity. Traditionally, children learning to hunt focus on small birds, including shorebirds. Shorebirds are a joyful part of nature and connect people with their environment, traditional culture, and language. Yup’ik people have noticed a decline in local shorebird numbers in recent decades. Based on traditional knowledge, they understand that animals, people, and the land are interconnected. If populations of shorebirds or other animals are not doing well, something is out of balance in nature, and that thing may finally also affect people.

Whether a harvest is sustainable depends on both harvest levels and on the status of the bird populations being harvested. Data gaps still prevent robust assessments of shorebird harvest sustainability, but Bar-tailed Godwit populations currently have low harvest potential, and recent sharp declines in shorebird populations mean that we need to account for uncertainty in harvest sustainability in our conservation efforts. Shorebirds now depend on citizens, biologists, and managers to protect and restore their habitats. It is important to include indigenous peoples and other stakeholders in shorebird conservation along flyways. This study is already the basis for culture-focused conservation outreach efforts in western Alaska. As a next step, we want to collaboratively develop conservation approaches that benefit shorebirds as well as the well-being of these subsistence communities. We all play a role in our relationships with nature!

Tracking Guam’s snake survivors

Henry Pollock

Linked paper: Pervasive impacts of invasive brown treesnakes drive low fledgling survival in endangered Micronesian Starlings (Aplonis opaca) on Guam by H.S. Pollock, J.A. Savidge, M. Kastner, T.F. Seibert, and T.M. Jones, The Condor: Ornithological Applications.

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A Micronesian Starling. Photo by Martin Kastner.

For bird aficionados, waking up on Guam can be a surreal experience. The soundscape is nearly devoid of birdsong other than the clucking of chickens and the occasional chirp of a Eurasian Tree Sparrow. Guam’s silent forests are the work of the brown treesnake, an invasive predator that was accidentally introduced to the island after World War II. Following its initial establishment on Guam, the brown treesnake population exploded, causing the extirpation of ten out of the island’s twelve native forest bird species within a few decades. However, a couple of species have managed to persist, and understanding how they’ve managed this feat in the face of such a formidable predator can inform future avian conservation strategies and snake suppression efforts on Guam.

Our research focused on the Micronesian Starling or Sali, a glossy black, gregarious bird that is a staple of forests throughout the Mariana Islands. On Guam, Sali declined precipitously following the introduction of the brown treesnake, but a small population has managed to persist in an urbanized landscape on Andersen Air Force Base in northern Guam. To understand why Sali have survived while so many other bird species have disappeared, we set out to study fledgling survival. The post-fledging period, when a bird has left its nest but is still dependent on its parents, is a period of great vulnerability, because young birds are often clumsy, sedentary, and less equipped to evade predators than adults.

To track fledglings through this crucial period, we attached small radio transmitters to Sali just before they left the nest and then came back each day to see whether our birds had survived the previous night and where they were spending their time. All of our birds fledged from nest boxes in an urban housing area, and tracking young birds through backyards on a military base was an interesting experience. We had regular run-ins with the military security forces, as well as also a lot of curious homeowners wondering what exactly we were doing decked out in field gear and holding large antennas! After a while, though, people got to know us, and many were truly interested in what we were doing and excited to know that they had a locally endangered bird species in their own neighborhood.

Our findings were staggering: only 25% of the fledglings survived, one of the lowest fledgling survival rates ever recorded for any bird species. The primary culprit was, of course, the brown treesnake, which caused approximately 60% of all mortality. However, cats were also an important source of mortality, responsible for around 20% of fledgling deaths. Beyond establishing these baseline numbers, however, we were also able to identify spatial patterns of predation risk and provide important management recommendations for future bird conservation on Guam.

We found that fledglings from nest boxes closer to the forest were more likely to be killed by brown treesnakes, indicating that locating nest boxes in core urban areas away from the forest perimeter would maximize fledgling survival. Furthermore, our data showed that brown treesnake predation actually extended weeks beyond the vulnerable post-fledging period, demonstrating again that these snakes are uniquely pernicious predators and that intensified snake control efforts are needed. We hope that our research provides impetus for further controlling the invasive brown treesnake and serves as a stepping stone for bringing birds back to Guam and enriching the island’s soundscape once again.

Studying “song neighborhoods” within sabrewing leks

Juan Francisco Ornelas

Linked paper: Male relatedness, lekking behavior patterns, and the potential for kin selection in a Neotropical hummingbird by C. González and J.F. Ornelas, The Auk: Ornithological Advances.

A Wedge-tailed Sabrewing. Photo by Clementina González.

About 25 years ago, I started a research position at the Instituto de Ecología AC in Veracruz, Mexico. During my first explorations of the cloud forest there, I heard the marvelous sound that eventually became a key part of my work and that of my assistant Clementina González. After spending my graduate school years at the University of Arizona and learning the sounds of the Sonoran Desert, I decided to tape record the unfamiliar sound, a decision that resulted in a great journey.

When I was field hunting for the sound, holding my old tape recorder, I soon heard swooshing noises and the mystery sound coming from somewhere in the bushes and thickets of the understory, but at first I could not see what was making it. Suddenly, I spotted it: a Wedge-tailed Sabrewing! These birds are among the most common hummingbirds in the area, or at least the most belligerent. Males are polygamous and (like all male hummingbirds) do not participate in raising the young, but this species forms leks, which are areas where males sing to show off and females choose mates.

Years later, Clementina started recording songs from different groups, and she realized that they sounded different. Once we were familiar with the behavior of Wedge-tailed Sabrewings, we documented the structure and variation of their songs within and between singing groups in central Veracruz. What we found was very exciting. Locally known as fandanguero (because it sings all day long like local folks at the fandangos), the Wedge-tailed Sabrewing has a song that is complex and variable, composed of more than 20 different syllable types per individual. We found a total of 239 different syllable types among the eight singing groups we studied.

This became the basis of Clementina’s doctoral thesis. She started to record songs from leks across their geographic distribution and showed that their song varies throughout eastern Mexico, where populations of three subspecies (curvipennis, excellens, and pampa) are disconnected. When she looked at their DNA, lek members clustered into the three subspecies and could also be distinguished by their songs. We wondered, what caused the genetic and behavioral differences? Genetic drift (the accumulation of random mutations in a population) could partially explain their genetic and behavioral differences, because the members of populations of one subspecies don’t mate with the others. But the genetic drift alone is not enough to fully explain the observed song variation within and among leks of each of the subspecies. Some sort of selection might be occurring.

We wanted to explore more deeply what was happening inside the leks. Clementina realized that males within a lek also sang differently and that males with different songs were clustered spatially, with an introductory syllable in their songs as the signature of a song neighborhood. It is not clear at this point in our research how and why these unique and variable complex acoustic signals have evolved in some but not all lekking species of hummingbirds, but we’re working on figuring it out.

For our newest study, published in The Auk: Ornithological Advances, we asked whether lek formation and the existence of song neighborhoods within leks are due to kin selection. In this system, kin selection would occur when a member of a song neighborhood engages in self-sacrificial behavior that benefits the genetic fitness of its relatives in the neighborhood. To address this, we genotyped males in leks located across the distribution of Wedge-tailed Sabrewings as well as in a focal lek composed of song neighborhoods and estimated their relatedness — not an easy task! Most males within leks were unrelated, and song neighborhoods were not composed of related individuals. This means that kin selection is not acting on the formation of leks or song neighborhoods in this species, suggesting that membership in song neighborhoods is achieved by learning the song of the neighborhood, regardless of kinship.

Clementina González website

Juan Francisco Ornelas website

Singing Above the Urban Ruckus, If You’re a Mockingbird

Mitchell Walters

Linked paper: Urban background noise affects breeding song frequency and syllable-type composition in the Northern Mockingbird by M.J. Walters, R.P. Guralnick, N.J. Kleist, and S.K. Robinson, The Condor: Ornithological Applications.

Northern Mockingbirds adjust their songs to noisy urban environments. Photo by Mitchell Walters.

Imagine having a conversation with someone next to a very busy intersection at rush hour. You can’t hear one another at a normal volume, so what do you do? You could talk louder, maybe wait for the noise to die down, or simply pick up your belongings and move to a quieter setting to converse.

Our research shows that if you’re a Northern Mockingbird, one of North America’s most famous avian songsters and the state bird of five U.S. states, you adjust to noisy settings by conversing at a higher pitch. Northern Mockingbirds’ songs are incredibly complex, made up of hundreds of different elements, and we also found that urban mockingbird songs include more high-pitched elements.

So why raise your pitch? Noise in urban environments overlaps most strongly with lower-frequency bird vocalizations, so mockingbirds may be increasing the pitch of their songs to avoid being drowned out by urban background noise. However, mockingbirds also love to mock things, so it’s possible that individuals mimic higher-pitched sounds more often in urban environments. In any case, the Northern Mockingbird is a great example of a bird adapting to urban habitat. Previous research in our lab has shown that not only is this species more abundant in urban areas, it also adjusts its nesting, foraging, and anti-predator behavior in these settings. The acoustic flexibility we found in our study may add to their ability to coexist with urbanization and people.

Because mockingbirds love to mock other bird species in their environment, it also makes sense to ask how much of a role surrounding bird communities play in the characteristics of their songs. This is important, because a male who’s a prolific impressionist may be very attractive to female mockingbirds. Future research aims to look at whether urbanization affects the quality of mockingbird songs via changes in bird diversity. If this is true, then human disturbance could be indirectly impacting the evolutionary trajectory not only of Northern Mockingbirds, but of other mimicking species as well.

When I started my master’s degree at the University of Florida, I actually had no intention of working with mockingbirds. I originally planned to do a project overseas, but my advisor and I quickly realized that was unrealistic. After a few mild panic attacks and brainstorming sessions I turned to urban ecology, a topic I had recently developed an interest in. Our lab had done long-term studies on urban mockingbirds, but no one had looked at what was, in my opinion, the most fascinating part of mockingbird life history — their songs. So the stage was set, the field gadgets were bought, and the grant proposals were accepted, sort of. After two years of blistering Florida summer heat and several strange encounters with locals asking what the heck I was doing with recording equipment, the project was complete and the results are now in! I just want to thank AOS for publishing my first first-author manuscript; it’s been an absolute pleasure working with this amazing journal.

AUTHOR BLOG: Lifting hunting limits hasn’t solved the Snow Goose overpopulation problem

Robert Rockwell

Linked paper: Liberalized harvest regulations have not affected overabundant Snow Geese in Northern Manitoba by D.N. Koons, L.M. Aubry, and R.F. Rockwell, The Condor: Ornithological Applications.


A large flock of snow geese during spring migration in North Dakota. Photo by Craig Bihrle, North Dakota Game and Fish Department.

As many marshes along the Gulf Coast were drained in the late 1970s, Snow Geese that had used them as wintering areas began shifting to agricultural land instead. Leftover crops in farm fields provided them with a generous new winter and spring diet, and the population began growing at an unprecedented rate. While they have ample habitat in the south, the growing number of geese, coupled with their destructive foraging behaviors, has led to increasing and widespread habitat destruction in the Arctic coastal habitats where they breed.

In response to this habitat degradation and the resulting negative impacts on other species, the U.S. and Canada attempted to reduce the size of the population by liberalizing the regulations on Snow Goose hunting beginning in 1997. This included increasing bag and possession limits, expanding the hours during which hunting is permitted, allowing the use of unplugged shotguns and electronic callers, and instituting a spring conservation harvest. Adult mortality has a greater relative impact on the growth rate of this species than any other demographic variable, so wildlife managers hoped that removing more adults from the population through hunting would help bring it under control.

Severely degraded coastal and near-coastal habitat in Wapusk National Park outside of Churchill, Manitoba, Canada. Photo by Stephen Brenner, Nebraska Game and Parks Commission.

Adaptive Harvest Management is an approach used in North America that examines the impacts of management decisions and readjusts those decisions as necessary to meet management goals. We used our 50-year database on more than 100,000 Snow Geese banded on Canada’s Cape Churchill Peninsula to assess whether the new regulations were having the desired effect of increasing adult mortality. Using new analytical techniques, we could estimate the rates of both hunter and non-hunter deaths of adult geese and see whether those rates changed when the new hunting regulations were implemented.

Adult harvest mortality has stabilized at a low level, with only around 3% of adult geese being killed by hunters in a given year, probably because the sheer abundance of Snow Geese in this population has overwhelmed the number of hunters. The number of North American hunters has not increased in recent years, and most hunters are only willing to harvest enough geese to meet their family’s needs. Adult non-harvest mortality declined through the 1970s and 1980s to trivial levels (around 1% per year), but has increased recently and now fluctuates between 10% and 19% per year. Unfortunately, the combined mortality isn’t enough to limit the species’ growth, and the population continues to increase in size.

In light of our results, the next cycle of Adaptive Harvest Management needs to consider the potential causes of the increase in non-hunting mortality and its year to year variability, especially since such variation actually reduces overall population growth rate. We also suggest that management agencies further refine hunting regulations to increase the harvest per hunter and make efforts to increase public participation in hunting, perhaps through outreach to currently underrepresented groups.

The authors are all associated with the Hudson Bay Project. More about our work can be found at http://research.amnh.org/users/rfr/hbp.