#GlobalAOS: Iliana Medina Guzmán

This July and August, we’re running a special series of blog posts profiling AOS members around the world, in honor of the recent change to AOS’s bylaws eliminated any reference specifying the Western Hemisphere as the Society’s geographic sphere of influence. This week, meet Iliana Medina Guzmán, a postdoctoral researcher in Australia.

Dr. Medina Guzmán with a screech-owl in her home country of Colombia.

What’s your current affiliation and title?

I am a postdoctoral researcher at the University of Melbourne in Australia.

What are you working on right now?

I work with the evolution of color in birds. I also work with brood parasitism from a broad perspective, like comparative analysis, that type of thing. Those are my two most recent interests. I am mostly on the computer — I use databases a lot for my work, because I do analyses on a lot of different species. I spend most of my time reading and looking for information on all of these species.

Recently we are working on how brood parasites target their host species based on territory size — do they target species that live in larger territories or smaller territories. So I go into the literature and try to find information for each species of host and non-host for average territory size, breeding densities, distribution, things like that.

Dr. Medina Guzmán working on her latest research project.

When did you join AOS, and why did you decide to join?

I just became a member last fall. I decided to join because I read a lot of papers from The Auk and The Condor, because for my comparative analyses I need information on the natural history of lots of different species, and those journals have a lot of that information. I published myself part of my thesis in one of those journals. And being an AOS member also includes access to databases like Birds of North America, which I also use for all of these comparative analyses. So that’s super useful. I thought AOS membership was a really great value for all the benefits that it brings.

I have to confess that I feel a bit like an impostor, because I consider myself an evolutionary biologist that happens to work with birds, not a real ornithologist. I’m more interested in the questions than the actual organisms, but I like birds a lot and I work with birds for most of my questions.

What do you see as the best benefit of being an AOS member?

Definitely the journals and Birds of North America! I haven’t been to any meetings or anything like that, so for me it would be the journals and the access to the databases.

#GlobalAOS: Patience Shito

This July and August, we’re running a special series of blog posts profiling AOS members around the world, in honor of the recent change to AOS’s bylaws eliminated any reference specifying the Western Hemisphere as the Society’s geographic sphere of influence. This week, meet Patience Shito, a master’s degree student in South Africa.

Patience observing captive hornbills.

What’s your current affiliation and title?

I’m currently a master’s candidate and an intern with the Mabula Ground Hornbill Project, based in South Africa.

What are you working on right now?

For my internship, I do a lot of education and awareness work about the Southern Ground Hornbill. We go out to schools and we do lessons and activities with the children, teaching them about the importance of the bird and why we are concerned about it, because it’s an endangered species in South Africa. We also go out and interact with rural communities and farmers and just the general public, be it at workshops or bird fairs or just gatherings where we’ve been invited to give talks, and we give talks here on the game reserve where we’re based, the Mabula Game Reserve. The Southern Ground-Hornbill is a culturally significant species in most ethnic groups throughout its range in Africa, and we aim to maintain that reverence through all age groups, as it has contributed to the persistence of the species in some areas.

Patience tracking ground hornbills in the field.

We also do research on the birds. Southern Ground Hornbills are a long-lived species, they live for about fifty years, and the research that’s been done on them hasn’t really covered all of the aspects of their biology and ecology as well as their interactions with humans here in South Africa. For my master’s thesis, I’m looking at the factors that are affecting the distribution of the birds in an area called the Limpopo River Valley, where ground hornbills are recolonizing the region after almost being wiped out in the 1960s and 1970s.

When did you join AOS, and why did you decide to join?

I applied for a Student Membership Award last year and received a year of free AOS membership. I applied because I realized that my knowledge was a bit lacking in terms of current trends in ornithology, and I just wanted to broaden my horizon in terms of what people are doing currently throughout the world. I realized that the American Ornithological Society has members throughout the world and I can possibly link up with them and find out what’s going on in matters pertaining to ornithology. In addition, I wanted to be able to apply for the Student Research Awards and possibly, hopefully, get some funding to complete my master’s studies.

What do you see as the best benefit of being an AOS member?

The best benefit is just opening up my mind to new ideas, from reading articles in the journals, and interacting with fellow ornithologists. It’s easy to be stuck in one track, one way of doing things, but if I can interact with more people, more ornithologists, to learn as much as I can, then I think I can go far in my career in ornithology.

Patience conducting an outreach program at a local school.

Press Release: Despite Habitat Protection, Endangered Owls Decline in Mount Rainier National Park

Spotted Owls in Mount Rainier National Park. Photo by Anna Mangan.

When the Northern Spotted Owl was protected under the Endangered Species Act in 1990, the primary threat to the species was the loss of the old-growth forest it depends on. However, new research published in The Condor: Ornithological Applications shows that the Northern Spotted Owl population in Washington’s Mount Rainier National Park has declined sharply in the past two decades despite the long-term preservation of habitat within the park. The culprit? The spread of Barred Owls, a closely related, competing species that has moved into Spotted Owls’ range from the east.

Biologists have seen Barred Owls in Spotted Owl territories within the national park more and more frequently since Spotted Owl surveys began in 1997. For their new study, Oregon Cooperative Fish and Wildlife Research Unit’s Anna Mangan, the National Park Service’s Tara Chestnut, and their colleagues analyzed two decades’ worth of data from these surveys. “We found that Spotted Owls now occupy 50% fewer territories in the park than they did 20 years ago when the study began, despite the lack of habitat disturbance,” says Chestnut. “Spotted Owls were less likely to be present in territories where Barred Owls were detected, and if Spotted Owls were there, sharing space with Barred Owls made them less likely to breed. Only 18 adult Spotted Owls were detected in the study area in 2016, down from a high of 30 owls in 1998.”

“Barred Owls eat a wider range of foods and use a greater variety of forested habitats, including the old-growth forest required by Spotted Owls, and these generalist traits have aided them in their highly successful range expansion throughout the Pacific Northwest,” explains co-author Katie Dugger, a researcher the US Geological Survey’s Oregon Cooperative Fish and Wildlife Research Unit. “Barred Owls are now competing with Northern Spotted Owls for food and space, and increased Barred Owl densities are associated with declines in Northern Spotted Owl populations across their range.”

“What is particularly alarming is that this decline has occurred even at Mount Rainier, where Spotted Owl habitat has been protected for over 100 years, with virtually no fire or logging disturbance,” says Mangan. “With Barred Owls detected at nearly every Spotted Owl territory monitored in the park, the future of Spotted Owls at Mount Rainier is tenuous. It also suggests that preserving owl habitat, while still crucial, is likely no longer enough to sustain the Spotted Owl population at Mount Rainier.”

If current trends continue, scientists predict that the Spotted Owl could be extinct in the region within approximately six to eight decades. “Conservation managers can focus on protecting old-growth habitat with steeper slopes, as we found this to have higher Spotted Owl occupancy, and can continue to monitor Barred Owl populations to better understand their effect on local Spotted Owl populations,” adds Mangan. “Managers will need to consider some creative solutions, and likely some unpopular choices, if the Northern Spotted Owl is going to be prevented from going extinct on public lands.”

Barred Owls reduce occupancy and breeding propensity of Northern Spotted Owl in a Washington old-growth forest is available at https://academic.oup.com/condor/article-lookup/doi/10.1093/condor/duz031.

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

Black-backed Woodpeckers & the Emerging Threat of Homogenous Forest Fires

Andrew Stillman

Linked paper: Nest site selection and nest survival of Black-backed Woodpeckers after wildfire by A.N. Stillman, R.B. Siegel, R.L. Wilkerson, M. Johnson, C.A. Howell, and M.W. Tingley, The Condor: Ornithological Applications.

A Black-backed Woodpecker visits its nest in a burned tree. Photo by Jean Hall.

It’s fire season again in northern California. In some parts of the state, the evenings will glow with those too-familiar burnt orange sunsets while residents keep a wary eye on the news. Although wildfire can sometimes be catastrophic to human life and property, the raging flames don’t usually create lifeless wastelands. Walk through a recently burned forest, and you’ll be met with a myriad of birdsong. Fresh herbaceous growth and numerous wildflowers dot the forest floor, and woodboring beetles gnaw their way through burned trees. Then — if you’re lucky — you’ll hear it: the accelerating drum of the Black-backed Woodpecker.

Black-backed Woodpeckers are strongly associated with recently burned forests in the western U.S. They colonize these habitats rapidly after fire to take advantage of abundant post-fire resources, such as the dead trees that provide nest sites and access to a feast of woodboring beetle larvae. These birds may be jeopardized by logging activities that can destroy or degrade post-fire habitat, and Black-backed Woodpeckers are sometimes used as an indicator species to guide management activities on the post-fire landscape.

But post-fire landscapes are changing. Many recent studies indicate that current environmental conditions are yielding larger, more severe wildfires that leave post-fire habitat conditions outside of the historical norm. Add that to threats from post-fire logging, and we urgently need to understand how habitat specialists like the Black-backed Woodpecker will respond to these new conditions.

My colleagues from The Institute for Bird Populations and the U.S. Forest Service and I examined how Black-backed Woodpeckers use burned forest when deciding where to breed and whether the factors that influence nesting habitat selection also influence nest success. Over the course of eight years, we located 118 Black-backed Woodpecker nests in areas burned by six different fires, carefully monitoring the fate of each and surveying the characteristics of the surrounding habitat. Black-backed Woodpeckers selected moderately-sized nest trees in areas of high dead tree density burned at high severity. They also tended to select nest sites towards the outer edges of high burn severity patches. While our results showed strong relationships between nest site selection and habitat characteristics, we were surprised to find that none of the habitat variables that we measured affected nest success. Only nest initiation date had a strong effect, with early-season nests typically showing more success than late-season nests.

Researchers take a break from collecting data in a patch of burned forest. Photo by Jean Hall.

We already knew that Black-backed Woodpeckers select nesting habitat with high densities of dead trees, but our results reveal an important nuance to this association with severely-burned forest. The birds in our study selected nest sites near the edges of severely burned patches — “ecotones” where the habitat transitions from severely-burned dead trees to intact living trees. The term for this is “pyrodiversity,” referring to the amount of variation in fire severity within an area and the different post-fire habitats that result. It seems that pyrodiversity is important for breeding Black-backed Woodpeckers. A related study, published recently in the Journal of Applied Ecology, found a similar positive association between pyrodiversity and the woodpeckers’ foraging habitat.

Changing fire regimes in the American West are leaving larger, more uniform areas of severely burned forest. This means less variation in post-fire landscapes, and potentially less habitat for pyrodiversity-loving species like the Black-backed Woodpecker. Our research suggests that land managers can manage burned forests to benefit Black-backed Woodpeckers by prioritizing retention of burned stands with dense dead trees located adjacent to areas burned at low severity or left unburned.

Reproduction Versus Immigration in North Carolina’s Piping Plovers

Chelsea Weithman

Linked paper: Growth of two Atlantic Coast Piping Plover populations by C.E. Weithman, S.G. Robinson, K.L. Hunt, J. Altman, H.A. Bellman, A.L. DeRose-Wilson, K.M. Walker, J.D. Fraser, S.M. Karpanty, and D.H. Catlin, The Condor: Ornithological Applications.

Plover Adult by Katie Walker
An adult Piping Plover with a numbered leg bad. Photo by Katie Walker.

The beach: the sun, the sand, the water. It’s a wonderful place to be in the summer, whether you’re a shorebird or a human. Beach-nesting shorebird species increasingly have to share the shore with recreationists and human development, and many species of shorebird have been declining as a result. One beach-nesting specialist is the Piping Plover, which nests on sandy beaches along the North American Atlantic Coast, the Great Lakes, and riverine and alkali lakes of the Great Plains. To aid the recovery of the federally threatened Atlantic Coast Piping Plover, wildlife managers try to reduce disturbance and predation risks on its breeding grounds so that the plovers can successfully raise more fledglings. The hope is that increasing the number of fledglings will lead to population growth and, eventually, species recovery.

As part of my graduate work, my coauthors and I studied the population dynamics of Piping Plovers at Cape Hatteras National Seashore and other parts of the North Carolina Outer Banks. North Carolina is a particularly interesting place for these little shorebirds, because it hosts plovers throughout the year. Plovers have been studied in other parts of their range for decades, but the North Carolina population has not received as much attention. Would this breeding population be any different?

Surveying 2
Researchers survey a beach for Piping Plovers. Photo by Chelsea Weithman.

Based on analysis of long-term reported population estimates and reproductive output, this population—along with others in Virginia, Maryland, and Delaware—was thought to potentially reap some benefit from its position in the southern end of the breeding range. Particularly, these plovers were hypothesized to have higher survival rates, since they don’t have to migrate as far to reach their breeding ground as their brethren in the northeastern U.S. and Canada do. Perhaps, then, these southern populations may not need to produce as many young each year to maintain their population. If true, this difference in survival rates could have implications for how we think about and evaluate the recovery of this species. We set out to examine this hypothesis by comparing two populations in different areas of the breeding range: one population on Fire Island, New York, and one in North Carolina.

Contrary to our expectations, we found that plovers in North Carolina and New York have very similar survival rates and presumably need to produce similar numbers of chicks per breeding pair to maintain their populations. The New York population has grown considerably over the decades, especially after Hurricane Sandy created vast new areas of ideal habitat in 2012. The North Carolina population, on the other hand, has not met the estimated reproductive rate needed to maintain their population for more than 30 years. Based on this result, our burning question was, how are there still plovers in North Carolina at all?

We believe that the population in North Carolina is being sustained by a constant influx of immigrants—instead of chicks growing up and taking the place of their parents, immigrants from outside the population are keeping their numbers up. However, we don’t yet know where these immigrants are coming from or what their departure means for their original populations’ growth prospects. We’re continuing to study this phenomenon in hopes of better understanding how and why plovers choose to disperse and join other populations. This is important for the bigger picture of plover conservation, since so much time, energy, and money are dedicated to the important work of improving reproductive success. If other factors such as immigration are key components of a population’s health, then management strategies may need to be developed to support them, too.