Songbird nestlings in the Arctic struggle in cold, wet years, but the changes forecast by climate models may lead to even more challenging conditions, according to new research in The Auk: Ornithological Advances.

Jonathan Pérez of the University of California, Davis, and his colleagues compared the growth rates of the nestlings of White-crowned Sparrows, which have a broad breeding range, with those of Lapland Longspurs, which are an Arctic breeding specialist. They predicted that nestlings would grow faster in warmer, drier conditions, that clutches laid earlier would do better, and that the nestlings of specialist longspurs would grow faster than the generalist sparrows.

They found that growth rates were higher overall in 2013 than in 2014, when the weather was colder and wetter. There were also fewer arthropods, the birds’ food source, available in 2014. Longspur nestlings grew faster than sparrow nestlings both years, but sparrows were unaffected by temperature, perhaps because sparrows nest in shrubs rather than on the open tundra. Nestlings from clutches that were laid earlier did grow faster than those from later clutches, since birds that arrived on their breeding grounds early could claim the best territories for raising young.

Challenging conditions force parents to make a choice between taking care of themselves and taking care of their offspring. Climate change is likely to bring new uncertainty for birds nesting in the Arctic—while warmer temperatures will favor higher nestling growth rates, climate models also predict more frequent storms and increased precipitation.

The research was carried out on the North Slope of Alaska’s Brooks Range, where researchers tracked 110 White-crowned Sparrow nestlings and 136 Lapland Longspur nestlings over two years, representing 58 total nests. Perez had previously studied parental energy expenditure and incubation. “When I became involved in our project based out of Toolik Lake looking at effects of interannual variation across trophic levels and how that ultimately plays out in terms of reproductive success of songbirds, expanding to an examination of nestling growth rates with regards to variation in environmental conditions seemed like a logical next step,” he says.

“Species at range edges are sentinels of climate change because they often experience high environmental variability and harshness,” according to Dr. Daniel Ardia of Franklin and Marshall College, an expert on the role of environmental variation in bird behavior and physiology. “Pérez and his co-authors reveal the direct effects of weather variation on nestling growth, an important determinant of fitness, showing how climate variability might have strong negative effects of populations. What makes the study so compelling is that they were able to link weather variability to food supply showing the causal link between predicted weather variation and reproduction.”

Nestling growth rates in relation to food abundance and weather in the Arctic is available at http://www.aoucospubs.org/doi/full/10.1642/AUK-15-111.1.

About the journal: The Auk: Ornithological Advances is a peer-reviewed, international journal of ornithology that began in 1884 as the official publication of the American Ornithologists’ Union. In 2009, The Auk was honored as one of the 100 most influential journals of biology and medicine over the past 100 years.

A new Review in The Condor: Ornithological Applications explores how oaks and pines depend on corvids, the group of birds that includes ravens, crows, and jays, to reproduce and spread—and how birds may be the key to helping these valuable trees weather the challenges of habitat fragmentation and climate change.

Corvids store seeds in small caches spread across the landscape, a behavior called “scatter-hoarding.” Birds cache more seeds than they eventually eat, so some seeds sprout and scatter-hoarding becomes seed dispersal, helping trees colonize new areas. Many oaks and pines have specific adaptations to encourage dispersal by birds, producing large, nutritious seeds with protective chemicals that keep them from rotting, which encourages scatter-hoarding by eliminating the need for animals to eat the seeds immediately.

The Review by Mario Pesendorfer of the University of Nebraska–Lincoln and his colleagues at the Smithsonian Migratory Bird Center, Cornell Lab of Ornithology, and The Nature Conservancy explores specific examples of such relationships from around the world. In Europe, Eurasian Jays are proving to be a crucial ally for oaks as habitat fragmentation and climate change increasingly impact European hardwoods. In the western U.S., researchers have shown that repeated long-distance dispersal events by Clark’s Nutcrackers are essential to establish and maintain Ponderosa Pine populations and that Pinyon Jays help maintain the tree’s genetic diversity. And in the eastern U.S., Blue Jays speed forest fire recovery by increasing their caching effort after fires and selecting canopy gaps as cache sites.

Harnessing this bird behavior may aid habitat restoration. Europeans have been aware of the relationship between jays and oaks for centuries, and managers in some areas of Western Europe are planting small stands of seed-source trees and relying on corvids to help disperse them across the landscape. In America, conservationists are exploring the possibility of reintroducing Channel Island Scrub-Jays to islands where they were extirpated to speed the recovery of oak and pine vegetation after livestock removal.

“In light of the globally changing climate and increasing habitat fragmentation, these winged dispersers that transport seeds over long distances are likely to become more important, as they enable plant populations to shift their range,” says Pesendorfer. “Since oaks and pines are important keystone species that themselves provide habitat for hundreds of animal species, such dispersal can have ecosystem-wide benefits.”

Scatter-hoarding corvids as seed dispersers for oaks and pines: A review of a widely distributed mutualism and its utility to habitat restoration is available

About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology. It began in 1899 as the journal of the Cooper Ornithological Club, a group of ornithologists in California that became the Cooper Ornithological Society.

Wading birds in many parts of the world use agricultural habitats such as flooded rice fields, but in the southeastern U.S., Great Egrets (Ardea alba) prefer natural wetlands over any other habitat type, according to a new study in The Condor: Ornithological Applications. Researchers tracking habitat use by Great Egrets in Louisiana and South Carolina found that while some human-influenced wetlands, such as ponds and crayfish production impoundments, did attract egrets, this preference varied between regions. Overall, Great Egrets preferred to forage in natural wetlands.

Human-influenced wetlands such as fish hatcheries, flooded agricultural fields, and artificial ponds and reservoirs represent a rising percentage of the world’s wetland areas, and in some areas these may offer enhanced foraging opportunities for wading birds. Jason Fidorra, formerly of the University of Florida and now with the Washington Department of Fish and Wildlife, and his colleagues captured Great Egrets in southern Louisiana and coastal South Carolina and fitted them with backpack transmitters to learn how these birds used available wetland habitats. They also conducted aerial surveys of a breeding population in Louisiana, where nesting colonies located on a boundary between agricultural and natural wetlands provided an ideal opportunity to observe the birds’ habitat preferences.

In both South Carolina and Louisiana, satellite tracking revealed that the most commonly used foraging habitat was natural wetlands; human-influenced ponds and lakes were the second most popular habitat type in South Carolina, while rivers were second-most popular in Louisiana. Satellite-tagged birds did not use flooded agricultural fields at all during the study. In aerial surveys, the only human-influenced habitat the egrets preferred to natural wetlands was impoundments for crayfish production, not rice fields.

Catching egrets required a bit of ingenuity. “We spent several months learning ways not to catch an egret, and the successful method was something I don’t claim credit for,” says Fidorra about the pneumatic net guns used in the study. “It was a colleague, Danny Caudill, who suggested it. Of course, since we were often working within urban areas we couldn’t use the actual guns that are normally modified to shoot nets. Instead, Caudill came up with some DIY instructions for an air-powered net gun that he pieced together at a hardware store for about $35. In the end it turned out to be a versatile and effective tool—and a lot of fun, of course.”

Their results show that despite the importance of agricultural fields for wading birds in some parts of the world, natural wetland habitat is usually preferred by Great Egrets in the U.S. “Rice fields have been fairly well studied as bird habitat in many parts of the world, but much less so in Louisiana,” says Fidorra. “We found that while Great Egrets did use rice fields, they were never selected more strongly than natural wetlands. This suggests that they are less-than-adequate replacements to natural wetlands.”

“Long-legged wading birds have long been emblematic of freshwater and estuarine wetlands, ponds, lakes and rivers. Their health and abundance is an expression of the productivity of those habitats that have been so altered by humans for agriculture and suburban development over the past century,” adds John Brzorad of Lenoir-Rhyne University, an expert on egret movements and energy requirements. “This study is an excellent reaffirmation of the conservation value of natural wetlands and will further stimulate research on the value of golf course, suburban and retention ponds using advancing telemetry methods.”

Selection of human-influenced and natural wetlands by Great Egrets at multiple scales in the southeastern USA 

About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology. It began in 1899 as the journal of the Cooper Ornithological Club, a group of ornithologists in California that became the Cooper Ornithological Society.

Gulls have learned to follow diving ducks and take the bottom-dwelling mussels that the ducks bring to the surface, a food source that would otherwise be inaccessible to them. Gulls are one of the most adaptable groups of birds, able to exploit a wide variety of food resources and respond to new opportunities, and a study forthcoming in The Auk: Ornithological Advances documents this previously unrecognized behavior in Herring Gulls (Larus argentatus) and Mew Gulls (Larus canus) on a brackish lagoon on the Germany–Poland border.

Ducks wintering on Szczecin Lagoon dive to the bottom to forage on zebra mussels, bringing clumps of mussels to the surface and regularly losing fragments in the process. To determine whether the gulls on the lagoon take advantage of this or if their presence while the ducks are foraging is only a coincidence, Dominik Marchowski of Szczecin University and his colleagues observed the behavior of the birds between October 2013 and November 2014, watching three species of duck—the Common Pochard (Aythya ferina), Tufted Duck (A. fuligula), and Greater Scaup (A. marila)—through spotting scopes. They recorded how intensely the ducks were foraging and whether any gulls were present, and they also collected gull pellets to confirm what they were eating.

The more ducks in a flock were foraging, the more likely gulls were to be present. Gulls’ behavior toward the ducks fell into two categories: They picked up mussel fragments that the ducks lost, a form of one-way symbiosis called commensalism, but also stole fragments from the ducks directly, which is called kleptoparasitism. Both methods allowed the gulls to gain access to food that, being poor divers themselves, they wouldn’t have been able to reach otherwise. Pellet analysis confirmed that the diet of the gulls at the lagoon changes dramatically when the ducks show up for the winter, shifting from mostly fish to mostly mussels.

“Gulls were initially on the margins of our research. Initially, their interaction with the ducks seemed obvious, but after analyzing the available literature, it turned out that little is known about it,” says Marchowski. “The marginal study became major, and we developed behavioral studies of birds and an analysis of pellets to confirm the scale of the phenomenon. In our opinion, these studies show that it’s worth watching the seemingly obvious behavior of birds more closely, because they can hide interesting interactions.”

“This investigation provides rare and convincing evidence that demonstrates how interspecific feeding interactions between Larus gulls and diving ducks influence community structure in the vicinity of the Baltic Sea,” adds Dr. Timothy White of NOAA’s Biogeography Branch, an expert on sea duck foraging. “It is gratifying to see how meticulous fieldwork, focused on behavioral observations and prey analysis, is continuing to broaden our understanding of community patterns, seabird feeding ecology and social interactions.”

Newly demonstrated foraging method of Herring Gulls and Mew Gulls with benthivorous diving ducks during the nonbreeding period is available at http://www.aoucospubs.org/doi/abs/10.1642/AUK-15-62.1.

About the journal: The Auk: Ornithological Advances is a peer-reviewed, international journal of ornithology that began in 1884 as the official publication of the American Ornithologists’ Union. In 2009, The Auk was honored as one of the 100 most influential journals of biology and medicine over the past 100 years.

How do birds evolve over generations? How do different bird populations diverge into new species? Ornithologists have been asking these questions since the days of Darwin, but rapid advances in genetic sequencing techniques in the last few years have brought answers more in reach than ever. A Review forthcoming in The Auk: Ornithological Advances describes some of the newest and most exciting developments in the field of “high-throughput sequencing,” a collection of techniques for studying broad regions of a genome rather than individual genes.

High-throughput sequencing has been dropping in cost and complexity; once only available to large research consortiums, these methods are now feasible for smaller labs that were previously limited to working with individual genes or with mitochondrial DNA. “It’s like going from seeing with a few light sensitive cells that can only detect the difference between night and day to a fully formed eye that can see all of the stars in the night sky,” says David Toews of the Cornell Lab of Ornithology, the lead author of the Review.

Because high-throughput sequencing data looks at many genes instead of just a few, it makes it easier to identify very subtle genetic differences between populations, such as the genetics underlying small differences in plumage patterns between different subspecies of Wilson’s Warbler. It can also provide a fresh look at the genetic changes that occur in “hybrid zones,” where the ranges of closely related species overlap and members of the species breed freely with each other, such as where Black-capped and Carolina Chickadees meet in Pennsylvania. The process of one species splitting into two, such as what may be happening with the coastal and inland subspecies of Swainson’s Thrush, is another intriguing area for study.

“Right now, genetic technology is advancing so fast that it is mind-boggling to keep up with the latest techniques, the questions that are becoming available to ask, and the answers that the data gives us,” says Jack Dumbacher of the California Academy of Sciences, an expert in bird molecular ecology who was not involved with the paper. “This is not only a review of what we are learning, but how we are learning it and what we need to be thinking about next. The paper should be a great source for students trying to figure out how to get into this complex field of modern ornithological genetics.”

“I think as the methods mature, so will the field—we are really in an exploratory stage with this data. I think once the questions and theory become more refined, we will be able to be more hypothesis-driven in the study of avian genomics,” adds Toews. “In the end, however, this is just a tool. I think the tool is a powerful one, but it is really in the application to interesting biological questions that the biggest advances will come.”

Genomic approaches to understanding population divergence and speciation in birds is available at http://www.aoucospubs.org/doi/full/10.1642/AUK-15-51.1. Contact: David Toews, toews@cornell.edu.

About the journal: The Auk: Ornithological Advances is a peer-reviewed, international journal of ornithology that began in 1884 as the official publication of the American Ornithologists’ Union. In 2009, The Auk was honored as one of the 100 most influential journals of biology and medicine over the past 100 years.

Birds stopping for a break during their grueling migratory flights face a difficult tradeoff: They need to fuel up with food as efficiently as possible, but they need to avoid predators while they do it. To learn more about how they make these choices about food availability and predator risk, Jennifer McCabe and Brian Olsen of the University of Maine’s Climate Change Institute spent two years capturing birds during fall migration along the coast of Maine. Their results, published in The Auk: Ornithological Advances, show that overall birds prefer to stop in habitat with plenty of dense vegetation in which they can hide from predators such as hawks. However, the longer the migration a bird is facing, the more likely it is to take risks in order to fill up with high-energy fruit.

The six sites they monitored in 2011 and 2012 on Maine’s coastal headlands and islands fell into two categories. At some, there was no conflict between food availability and shelter from predators—birds could get both at the same time. However, at others, birds could only access the best food resources by venturing out into the open. Over the course of their two-year study, McCabe and Olsen captured almost 10,000 birds belonging to 28 species, and they found that bird abundance was higher overall in sites that didn’t force a tradeoff. The authors speculate that migrants quickly assess a site’s safety and productivity, and if a tradeoff is required, they soon move on.

While previous studies had looked at how individual species responded to these competing pressures, McCabe and Olsen’s study is unique in that it encompassed all the fruit-eating migratory birds in the area. “The neatest aspect of the study was that we used the entire migratory community to look at tradeoffs between foraging and predator avoidance similarly to behavioral research on single species, and we found similar results at the community scale as single species studies did,” says McCabe.

Habitat patches that maximize both food availability and vegetation to hide in are not the same as the mature, intact forests many songbirds prefer to breed in. Instead, they tend to be in places such as brushy forest edges, and the authors recommend that if wildlife managers want to support birds during migration as well as the breeding season, this sort of habitat cannot be overlooked, even if it appears less than pristine.

“Hawks, primarily falcons, are found in large numbers on Maine’s coastal islands during fall migration, keying in on the songbirds on migration stopover in the region. McCabe and Olsen’s manuscript does a brilliant job of assessing the balance between risking predation and fueling the energy demands for migration at six bird-banding stations along the Maine coast,” according to Glen Mittelhauser of the Maine Natural History Museum. “Overall, a well-done study that has advanced our knowledge of migration tradeoffs between food and safety and got us thinking about the importance of food resources and microhabitat on these coastal islands.”

Tradeoffs between predation risk and fruit resources shape habitat use of landbirds during autumn migration is available at http://www.aoucospubs.org/doi/full/10.1642/AUK-14-213.1. Contact: Jennifer McCabe, jennifer.mccabe@maine.edu.

About the journal: The Auk: Ornithological Advances is a peer-reviewed, international journal of ornithology that began in 1884 as the official publication of the American Ornithologists’ Union. In 2009, The Auk was honored as one of the 100 most influential journals of biology and medicine over the past 100 years.

Common Loons (Gavia immer) nest on lakes across Canada and the northern U.S., but every winter they disperse, many to the open ocean where they’re difficult to track. It’s been well established that many loons return to the same nesting sites every spring, but new research in The Condor: Ornithological Applications shows for the first time that they are similarly faithful to their wintering sites. Over the course of nearly 15 years, James Paruk of the Biodiversity Research Institute and his colleagues used a combination of methods to investigate winter site fidelity at four locations across North America and found that birds had an 85% chance of returning to a site in subsequent years. Because loons’ coastal wintering habitats can be severely impacted by oil spills and other human activities, this information has important implications for wildlife managers.

Common Loons have an enormous winter range, including nearly all of North America’s coastlines as well as some large freshwater reservoirs. Paruk and his colleagues collected data at four sites spread across the continent, three on the coasts of Maine, Louisiana, and California and one at an inland reservoir in Washington. In Louisiana, California, and Washington they captured loons and gave them leg bands in unique color patterns so they could recognize individuals and determine which ones came back, while in Maine they outfitted loons with satellite transmitters. Both methods showed the same result: the birds had a high probability of returning to the same wintering sites year after year.

The researchers speculate that loons benefit from the local knowledge they gain from returning to the same area again and again; they can learn the best spots to find food and hide from predators, which can be especially important for loons in winter. Adult loons go through a molt in winter that leaves them temporarily unable to fly, making it especially important to select a good site to spend the winter.

“Our finding was one of the last key unknowns about Common Loon natural history, and it was good to get some solid data on this topic,” says Paruk. Collecting that data, however, was something of an adventure. “While catching loons in 2014, I was at the bow, and the captain called to me to pick up a buoy-type bottle bobbing in the ocean. As we approached, I leaned over the bow and picked it up, and just beneath, and scaring the daylights out of me, was a four-foot sand shark! It just missed me, and made me feel quite out of my element.”

A number of marine oil spills have impacted Common Loon wintering habitat in recent decades, and the more loons return to the same contaminated areas, the more their breeding success and ability to survive could be affected by chronic exposure. For conservationists, this new piece of information about the life history of loons could be an important key for keeping populations healthy, so that these iconic birds can continue to knit together forest lakes and far-flung coasts for a long time to come.

Winter Site Fidelity and Winter Movements in Common Loons (Gavia immer) Across North America is available at http://www.aoucospubs.org/doi/full/10.1650/CONDOR-15-6.1. Contact: James Paruk, jim.paruk@briloon.org.

About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology. It began in 1899 as the journal of the Cooper Ornithological Club, a group of ornithologists in California that became the Cooper Ornithological Society.

Birds of a feather may flock together, but that doesn’t mean they share a genetic background. Though birds were first classified into groups primarily based on appearance, research forthcoming in The Auk: Ornithological Advances by Brett Benz of the American Museum of Natural History, Mark Robbins of the University of Kansas Biodiversity Institute, and Kevin Zimmer of the Los Angeles County Museum of Natural History demonstrates that this method isn’t necessarily accurate: in a group of very similar-looking South American woodpecker species, genetic analysis has now shown one to be only a distant cousin of the others, in an intriguing case of visual mimicry. By copying the appearance of larger, socially dominant woodpecker species, it reduces the aggression and competitive interference that it receives from them and has more access to food resources as a result.

The most familiar type of mimicry typically involves warning or “aposematic” coloration, in which a harmless species apes the color patterns of a dangerous or unappealing one to avoid predators; a famous instance is the Viceroy butterfly, which shares the striking colors of the more noxious Monarch. By contrast, the Helmeted Woodpecker (Dryocopus galeatus) represents an example of a different and less well understood form of mimicry, known as interspecific social dominance mimicry or ISDM.

The shy and little-known species shares the red crest, black back, and barred underside of two larger woodpeckers, Dryocopus lineatus and Campephilus robustus, all of which occupy the same habitat and share similar food preferences. The Helmeted Woodpecker’s similarity in appearance makes the larger, more dominant woodpecker species less likely to attack it, due to the costs of aggression between members of the same species. Though they had been previously classified in Dryocopus due to the remarkable similarities in their appearance, genetic analysis by Benz and his colleagues suggests that the Helmeted Woodpecker is actually not closely related to other Dryocopus woodpeckers at all and belongs in a different genus, Celeus. An independent group of researchers using the same data recently reported similar results in a paper published in the Journal of Ornithology.

“Co-author Mark Robbins and I had just finished a phylogenetic study examining species limits and vocalizations in Celeus woodpeckers when Mark, who was attending a meeting in Brazil, had the opportunity to observe a Helmeted Woodpecker at Intervales State Park,” according to Benz. “Upon hearing the bird vocalize, Mark was stunned that its call sounded nothing like Neotropical Dryocopus, and immediately knew we needed to examine its taxonomic status in the context of our recent Celeus study given that the Helmeted Woodpecker calls were most similar to several other Celeus species. Upon returning from Brazil, Mark consulted with co-author Kevin Zimmer, who had independently arrived at the same conclusions about the Helmeted Woodpecker belonging with Celeus, based on his behavioral observations spanning 20 years of fieldwork in Brazil.” As Benz puts it, “The Helmeted Woodpecker is basically a typical Celeus in Dryocopus clothing.”

“After several decades working on the discovery of the avian Tree of Life, it is still amazing what we are discovering! Reconstructing the phylogeny of these woodpeckers has corrected a century-old classification mistake, but more interestingly, it has revealed an unexpected new example of avian mimicry,” adds Richard Prum of Yale University, one of the originators of the ISDM hypothesis. “It has only recently been appreciated that small species may benefit from deceptively mimicking larger species to protect themselves from aggressive attack. This is similar to how a 12-year-old kid walking home from school will look and act tough to try to prevent himself from being harassed by older, bigger kids.”

Relatively little is known about the ecology and natural history of the Helmeted Woodpecker, which is found in Brazil, Paraguay, and Argentina, but it has experienced dramatic population declines and vanished from much of its former range due to deforestation. Hopefully, this new discovery about its evolutionary relationships and visual deception may increase interest in the species, as it provides an opportunity for scientists to further test predictions associated with ISDM. Ultimately, bringing the Helmeted Woodpecker’s sneaky strategy into the light may be what saves it from oblivion.

Phylogenetic relationships of the Helmeted Woodpecker (Dryocopus galeatus): A case of interspecific mimicry? will be published on September 30, 2015, and will be available at http://www.aoucospubs.org/toc/tauk/132/4; a pre-print version is available at http://dx.doi.org/10.1101/023663. Contact: Brett Benz, bbenz@amnh.org.

About the journal: The Auk: Ornithological Advances is a peer-reviewed, international journal of ornithology that began in 1884 as the official publication of the American Ornithologists’ Union. In 2009, The Auk was honored as one of the 100 most influential journals of biology and medicine over the past 100 years.

(July 22, 2015, The Auk: Ornithological Advances)—Animal populations on islands tend to develop weird traits over time, becoming big (like Galapagos tortoises) or small (like extinct dwarf elephants) or losing the ability to fly (like the flightless parrots of New Zealand). One less-studied pattern of evolution on islands is the tendency for animal populations to develop “melanism”—that is, dark or black coloration. J. Albert Uy and Luis Vargas-Castro of the University of Miami found an ideal species to study this phenomenon in the Chestnut-bellied Monarch (Monarcha castaneiventris), a bird found in the Solomon Islands. Most have the chestnut belly suggested by their name, but in the subspecies found in the Russell Islands, a few all-black birds coexist with the chestnut-bellied majority. After visiting 13 islands of varying sizes to survey their Chestnut-bellied Monarch populations, Uy and Vargas-Castro confirm in a new paper published this week in The Auk: Ornithological Advances that island size predicts the frequency of melanic birds, with populations on smaller islands including more dark individuals.

Because the pattern is repeated on island after island, it is very unlikely to have developed through random chance; instead, dark coloration must provide some sort of benefit to birds on small islands. Studies in mammals and fish have found a genetic link between melanism and aggressive behavior, and Uy and Vargas-Castro speculate that the limited space available on smaller islands makes competition for breeding territories more intense, giving an advantage to the most aggressive individuals. Previous experiments with other Monarcha castaneiventris subspecies using taxidermied birds and recorded songs have shown that melanic birds react more aggressively than their chestnut-bellied counterparts when they perceive a threat to their territory.

Uy had been fascinated by Chestnut-bellied Monarchs ever since reading a description of their plumage variations in Ernst Mayr’s seminal book on speciation, Systematics and the Origin of Species from a Viewpoint of a Zoologist, when he was a graduate student. “I was hooked and longed to work on the group,” he says. “I thought this would be the perfect species to explore these questions about the ecology of plumage diversification and the origin of species, as the variable populations of the chestnut-bellied flycatcher may be at different stages of the speciation process. It took me over a decade to finally manage to get to the Solomons, and I’ve been working on these flycatchers now for nearly 10 years.”

“Patterns of biodiversity on islands have always been important for understanding fundamental principals in ecology and evolution. Using the same archipelago that enchanted Ernst Mayr decades ago, Uy and Vargas-Castro reveal fascinating patterns of melanism and island size,” adds Rebecca Safran of the University of Colorado, an expert on divergence between bird populations who was not involved in the study. “These patterns add to the fundamental importance of islands as natural experiments for studies in biodiversity.”

Island size predicts the frequency of melanic birds in the color-polymorphic flycatcher Monarcha castaneiventris of the Solomon Islands is available at http://www.aoucospubs.org/doi/full/10.1642/AUK-14-284.1. Contact: J. Albert Uy, uy@bio.miami.edu.

About the journal: The Auk: Ornithological Advances is a peer-reviewed, international journal of ornithology that began in 1884 as the official publication of the American Ornithologists’ Union. In 2009, The Auk was honored as one of the 100 most influential journals of biology and medicine over the past 100 years.

(July 22, 2015, The Condor: Ornithological Applications)—Reintroducing a species into an area where it has vanished can be a great tool for conservation, but for reintroduction to be successful it’s crucial to understand how the habitat has changed in the interim and whether the reintroduced species will be able to thrive in its former home. Extirpated in the 1960s as a result of human activity, Bald Eagles (Haleiaeetus leucocephalus) have been reintroduced to California’s Channel Islands over the last 35 years. A study published this week in The Condor: Ornithological Applications examined the diets of these reestablished eagles in 2010 and 2011 to see how they compared to the diets of historical population. Like historical eagle populations, the reintroduced eagles in the Northern Channel Islands rely heavily on seabirds, according to authors Seth Newsome of the University of New Mexico, Paul Collins of the Santa Barbara Museum of Natural History, and Peter Sharpe of the Institute for Wildlife Studies. They also found that eagles on nearby Santa Catalina Island eat mostly fish, likely due to differences in human activity and a lack of seabird colonies on the island.

Newsome and his colleagues used two independent approaches to see what the eagles were eating—they collected the remains of prey from eagle nests, and they analyzed carbon and nitrogen isotopes in the eagles’ feathers. The isotope findings were then compared to those from potential prey to determine what animals the eagles were eating. Both methods found the same results. “Generally speaking, the northern islands are much more pristine, and a larger fraction of their coastlines includes areas where fishing is strongly regulated or banned. Santa Catalina, on the other hand, has a larger human footprint, especially in the form of recreational fishing,” explains Newsome. “We believe that the differences in diversity of fish consumed by eagles in these two areas is actually a product of recreational fishing, and that eagles on Santa Catalina have learned to follow recreational fishing boats and scavenge discards thrown overboard.”

The Northern Channel Islands eagles’ reliance on seabirds shows that successful seabird conservation efforts in the region have had benefits across the ecosystem. “As a community ecologist, I feel that the re-establishment of species at all trophic levels, including top predators like Bald Eagles, is the ultimate goal for animal conservation,” says Newsome. “Preserving diversity is wonderful, but you need to preserve diversity at all levels in the food chain. At present, such intact fully-functioning food webs are relatively rare in the United States, but to see that happen in a place like the Channel Islands that is adjacent to an area with one of the highest human population densities in the U.S. (southern California) is exciting.”

The number of eagles currently nesting on the islands is still below historic levels, so this fledgling population likely has room to expand. Exploiting both historical food sources and new ones made available by human activity, Channel Islands eagles are a success story for ecosystem recovery.

Foraging ecology of a reintroduced population of breeding Bald Eagles on the Channel Islands, California, USA, inferred from prey remains and stable isotope analysis is available at http://www.aoucospubs.org/doi/full/10.1650/CONDOR-14-213.1. Contact: Seth Newsome, newsome@unm.edu.

About the journal: The Condor: Ornithological Applications is a peer-reviewed, international journal of ornithology. It began in 1899 as the journal of the Cooper Ornithological Club, a group of ornithologists in California that became the Cooper Ornithological Society.