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.

PRESS RELEASE: Study Reveals Key Locations for Declining Songbird

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Many of North America’s Prothonotary Warblers winter in the same small area of Colombia. Photo by Joan Eckhardt.

Many of North America’s migratory songbirds, which undertake awe-inspiring journeys twice a year, are declining at alarming rates. For conservation efforts to succeed, wildlife managers need to know where they go and what challenges they face during their annual migration to Latin America and back. For a new study published by The Condor: Ornithological Applications, researchers in six states assembled an unprecedented effort to track where Prothonotary Warblers that breed across the eastern U.S. go in winter—their “migratory connectivity”—and found that nearly the entire species depends on a relatively small area in Colombia threatened by deforestation and sociopolitical changes.

The Ohio State University’s Christopher Tonra and his colleagues coordinated the deployment of 149 geolocators, tiny devices that use the timing of dawn and dusk to estimate birds’ locations, on Prothonotary Warblers captured at sites across their breeding range. When the birds returned to their nesting sites the following year, the researchers were able to recover 34 devices that contained enough data for them to use. The geolocator data showed that regardless of where they bred, most of the warblers used the same two major Central American stopover sites during their migration and spent the winter in a relatively small area of northern Colombia. Additionally, many Prothonotary Warblers appeared to winter in inland areas, rather than in coastal mangrove habitat, which previous studies suggested they relied on most heavily.

These unexpected findings show that we may not understand the winter habitat needs of migratory songbirds as well as we thought. “The most surprising thing about the results was the overwhelming importance of Colombia to this species,” says Tonra. “We weren’t sure what to expect in terms of migratory connectivity, but we never expected that nearly every bird would use the same wintering region. This provided a clear conservation message and shows the power of geolocators in addressing gaps in our knowledge of migratory songbirds.” Colombia’s 50-year civil war accelerated deforestation in the region of the country where the warblers are concentrated, but the good news is that the convergence of birds in this single area means that conservation efforts targeted here could benefit breeding populations across North America.

Collecting data on birds across such a broad geographic area required close collaboration among the study’s thirteen coauthors. “This was very much a team effort, but it really started with Erik Johnson at Audubon Louisiana and Jared Wolfe with the Louisiana Bird Observatory,” says Tonra. “Erik founded and leads our Prothonotary Warbler Working Group, and he initiated the idea of deploying tags across their range. This was an extremely rewarding example of what you can accomplish through collaboration across the range of a species of concern. Everyone put in an enormous effort to gather data in their region, as well as contributing to the preparation of the paper.”

Concentration of a widespread breeding population in few critically important nonbreeding areas: Migratory connectivity in Prothonotary Warbler is available at https://academic.oup.com/condor/article-lookup/doi/10.1093/condor/duz019.

About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology, published by the American Ornithological Society. For the past two years, The Condor has had the number one impact factor among 27 ornithology journals.

PRESS RELEASE: UV Lights on Power Lines May Help Save Sandhill Cranes

Illuminating power lines with UV lights could reduce collisions by Sandhill Cranes. Photo by James Dwyer, EDM International.

Crane species are declining around the world, and lethal collisions with power lines are an ongoing threat to many crane populations. Current techniques for marking power lines and making them more visible to cranes aren’t always effective, but new research published in The Condor: Ornithological Applications shows that adding UV lights—to which many birds are sensitive—can cut crane collisions with power lines by 98%.

EDM International’s James Dwyer and his colleagues created what they dubbed the Avian Collision Avoidance System, or ACAS, by mounting UV lights on power lines’ supporting structures and shining them on the lines at night. They tested its effectiveness in 2018 at Nebraska’s Iain Nicolson Audubon Center, where a power line crosses the Central Platte River in key habitat for migrating Sandhill Cranes. Randomly assigning the ACAS to be on or off each night, they observed the behavior of cranes flying along the river at dusk and during the night. They documented 98% fewer collisions and 82% fewer dangerous flights when the ACAS was on and showed that cranes reacted sooner and with more control to avoid hitting the power lines.

“This project came about as a result of years of studying avian collisions with power lines throughout North America. My studies included collisions involving numerous species and families of birds, even on lines modified to industry standards to mitigate avian collisions, and I thought perhaps there could be a more effective approach,” says Dwyer. “Even so, I did not imagine that the ACAS would have the effect that it did—a 98% reduction in collisions! I thought it would have some effect, but I didn’t dare think the ACAS would pretty much solve the Sandhill Crane collision problem at our study site on our first try.”

The Avian Collision Avoidance System at night. Photo by James Dwyer, EDM International.

Conventional line markers were already in place on the power lines crossing the Central Platte River, and Dwyer and his colleagues speculate that the ACAS illuminated them and made them easier for cranes to see. “We don’t know how effective the ACAS will be on wires without line markers, so we’re testing that now,” says Dwyer.

“I hope to see the ACAS applied to and studied on other power lines and on communication towers to identify whether it is as effective with other species, habitats, and wire configurations,” he continues. “From there, if the ACAS proves broadly effective, I hope to see it made easily available to the global electric industry. I also very much hope to see collision studies expanded. Because large carcasses like those of cranes and waterbirds are more easily noticed than smaller species like sparrows and warblers, collision studies have mostly focused on those larger species, and I fear that we may not understand the true distribution of species and habitats involved in the global avian collision problem.”

Near-ultraviolet light reduced Sandhill Crane collisions with a power line by 98% is available at https://academic.oup.com/condor/article-lookup/doi/10.1093/condor/duz008.

About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology, published by the American Ornithological Society. For the past two years, The Condor has had the number one impact factor among 27 ornithology journals.

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.