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

Lifting Hunting Limits Hasn’t Solved the Snow Goose Overpopulation Problem

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.

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

UV Lights on Power Lines May Help Save Sandhill Cranes

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 …

owl specimens
Dorsal and ventral views of specimens of the two Saw-whet Owl forms, showing plumage differences. Photos by Jack Withrow.

Speciation with Gene Flow in Northern Saw-whet Owls

Scientists have long thought that for two related populations of birds to evolve into separate species, they needed to be completely separated. This usually means the kind of total separation produced by isolation on islands or by features such ice sheets, mountain ranges, or rivers. However, the complex distributions and migratory nature of many birds mean that long-term total separation of bird populations, long the assumption in speciation research, is actually not necessary for speciation to occur.

black-throated blue warblers in captivity
A female and male Black-throated Blue Warbler in captivity. Photo by Jessica Deakin.

Getting to the Bottom of Male Black-Throated Blue Warblers’ Migratory Behavior

Many species of migrant songbirds have a reproductive strategy called protandry, where males arrive at stopovers and breeding sites earlier than females. Ornithologists believe that males do this because it increases their mating opportunities and reduces competition among males for high-quality nest sites. Although it’s a common phenomenon, the question of how males arrive earlier is still unanswered for most species.

graph from study
The greater the magnitude of nuthatch’s winter irruption, the lower the next summer’s breeding population.

Do Songbirds Pay a Price for Winter Wandering?

In years when winter conditions are especially harsh, birds that depend on conifer seeds for food are sometimes forced to leave their homes in northern forests and wander far from their normal ranges to find enough to eat. A new study published in The Auk: Ornithological Advances uses citizen science data to show for the first time …

Are Homebody Warblers More Likely to Sing Together?

Scientists who want to study the evolution of behavior face a fundamental problem: unlike bones, behavior generally doesn’t fossilize. However, that doesn’t mean that extinct species’ behavior doesn’t leave any evidence. The behavior of living or “extant” species can give us clues about the behavior of their ancestors, and we can use the behavior of living species, the evolutionary relationships among species, and computational modelling to make inferences about extinct species’ behavior.

scrub-jay specimens
Devon DeRaad lines up Woodhouse’s Scrub-Jays (left) and Sumichrast’s Scrub-Jays (right) to compare back color between the forms. Photo by John McCormack.

How Do Traits Change Across a Scrub-Jay Hybrid Zone?

Where should we draw the line between species? Biologists have debated this question for over 100 years. For much of that time, Ernst Mayr’s Biological Species Concept, which defines a species as a group of individuals that is reproductively isolated from other groups, has dominated the conversation. Recently, however, more and more evidence of hybridization between species has accumulated, especially in birds.