General Meeting – May 2023 Tom Hahn, University of California, Davis: Natural History of Western Finches

Finches are, in many respects, the archetype of what people think of when they hear the word “bird.”  Yet concealed in that “typical bird” form lies amazing variation.  Among our numerous western finches – goldfinches, siskins, crossbills, grosbeaks, and so forth – we have: birds that are about as likely to breed in January when the snow lies deep on the ground as they are in July, birds that perfectly match the calls of their mates, birds that pack their songs with precise imitations of the sounds of other species, birds that seldom breed in the same place two years running, birds that we can only tell apart reliably by their flight calls, birds that can breed “in the streaked plumage of youth,” birds who can nest far from their food sources because they possess hefty food-transport pouches, and birds whose mandible tips don’t even line up.  This presentation will be a tour of the striking natural history, behavior, morphology, and physiology of our western finches, and highlight ways that field ornithologists and bird watchers can add to our growing knowledge about these fascinating birds.

Tom Hahn is a professor of biology at the University of California, Davis.  He has been studying western Cardueline finches since the late 1980s, when he began working on reproductive schedules of red crossbills for his doctoral research.  Since then, he and his students have spent many hours in the field studying the reproductive schedules, migratory habits, vocal behavior, habitat associations and other aspects of the natural history of red crossbills, white-winged crossbills, evening grosbeaks, pine siskins, house finches, Cassin’s finches, purple finches, American goldfinches, lesser goldfinches, pine grosbeaks, common redpolls and gray-crowned rosy-finches.