AUTUMN 2006/VOLUME 20, NUMBER 4
Brainy Birds Stay Behind
Resident birds have bigger brains than migrants, study finds
How can warblers and other long-distance
migrants fly so far with such tiny brains? Some Blackpoll Warblers travel 10,000 miles from Alaska to Brazil and back each year. It may seem that their navigational abilities would require incredible
intelligence. However, a recent study suggests that resident birds may have even more smarts than migratory birds since they have figured out how to find food year-round despite dramatic seasonal changes.
Resident songbirds have larger brains than long-distance migrants, according
to the study by McGill University researcher Daniel Sol and colleagues (Proceedings of the Royal Society, June 2005). The researchers also found that the resident birds were more inventive foragers, suggesting a possible link between
bigger brains and the ability to find food in northern winters.
by Katherine A. Smith
The study suggested that resident songbirds have relatively large brains?perhaps because
they must be innovative to find food during northern winters.
by Katherine A. Smith
Although long-distance migrants must navigate
across thousands of miles, they have smaller brains than resident
songbirds with similar body size.
Sol and collaborators compared data on the brain sizes of 105 songbird species
from Europe, the Middle East, and North Africa. After adjusting for the birds? body size, they found that long-distance migrants have smaller brains than short-distance migrants. Resident birds have the biggest brains of all.
The researchers also found that long-distance migrants tended to be less innovative
in their foraging behaviors than short-distance migrants and residents. These results were based on data from 68 common breeding birds in the British
Isles, where scientists have recorded extensive observations about the variety of foods the birds eat and their innovative
approaches to finding food?such as using a twig to clear snow from a food source.
Sol et al. suggested that big-brained resident birds are able to develop new foraging techniques to help them find food in a wider variety of places than migratory birds. They point out that it is not yet known which came first—migration
strategies or smaller brain size.
The bigger brains and behavioral flexibility of resident birds may be what enabled them to avoid traveling thousands of miles each year in search of food. The researchers speculate that innovative abilities may also make resident birds more resilient against environmental changes, such as habitat destruction or global warming.
—Anne Marie Johnson, Project FeederWatch assistant
This November, Project FeederWatch will begin its 20th season with more than 12,000 participants, 128 of whom have been sending their bird counts to the Lab since the project began in 1987.
Help Project FeederWatch by reporting sightings from your bird feeders. To join, visit www.birds.cornell.edu/pfw or call (607) 254-2427.
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: email@example.com