Neighborhood Prospects

Staff scientist Wesley Hochachka explains new findings about how birds decide where to settle down

A Collared Flycatcher investigates a potential place to nest. Photo by Joanna Sendecka

Choosing a neighborhood in which to live is an important decision, but knowing where you want to live and being able to afford it may be two different matters. In this respect, humans are very much like birds, according to a recent study by Blandine Doligez and colleagues (Journal of Animal Ecology, January 2004).

On the island of Götland, east of the Swedish mainland, the researchers found that young Collared Flycatchers settled in different kinds of neighborhoods than did their elders. Before departing on migration in fall, the flycatchers apparently scouted out places to live for the following year. When they returned in spring, some of the flycatchers moved to new breeding locations. Those that did preferred to settle in areas where the nesting density had been high the previous summer. However, older flycatchers also chose areas where many young had fledged, whereas first-time parents did not. The authors suggest that young breeders opted to avoid the best areas so they wouldn?t have to compete with more experienced birds.

During the study, the researchers placed nest boxes in 20 separate patches on the island. They kept track of the density of breeding birds in each patch and the average number of offspring raised. By marking almost all of the flycatchers with individually numbered bands, they were able to document whether birds switched nesting locations from year to year, and if so, where they ended up.

The results have many implications, but two points in particular jumped out at me. First, this study indicates how important it is for birds, even newly independent juveniles, to travel widely in fall, gathering the information on which to base their decisions about where to nest the next year. Second, it suggests that from a conservation perspective, it may not be effective to set aside only a few patches of ?ideal? habitat. If this were done, there might not be sufficient space for younger birds that would start their nesting careers in less-than-ideal habitat and move into better patches in the future. Additionally, the study found that patches that are the best in one year might not be the best several years later, suggesting that short-term studies used to assess habitat quality might give misleading information for long-term conservation.

—Wesley Hochachka

For permission to reprint all or part of this article, please contact Laura Erickson, editor, Cornell Lab of Ornithology, 159 Sapsucker Woods Rd., Ithaca, NY, 14850. Phone: (607) 254-1114. email: lle24@cornell.edu