How do migrating birds avoid predators while fueling up?

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.

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Songbird habitat affects reproduction, survival

A University of Montana professor who studies birds around the world has discovered trends in how the offspring grow, how parents care for the young and how well the young survive based on where they live. Now, his songbird research is hitting the right notes with the journal Science.

Thomas Martin, assistant leader of the U.S. Geological Survey Montana Cooperative Fish and Wildlife Research Unit at UM, set out to explain why tropical birds tend to have fewer offspring that seem to grow slower and live longer, slower lives than their northern counterparts. He found tropical songbirds grow their wings faster, aided by higher parental feeding rates for fewer offspring than temperate species. Those differences, Martin said, ultimately translate to how well the offspring escape predators both in the nest and after they leave it.

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