The evening grosbeaks (Coccothraustes vespertinus) are behaving differently this winter. Our usual pattern of evening grosbeak sightings are consistent with their irruptive (irregular) migratory behavior, which is often in response to food supply. They usually arrive in a flock each spring, strip the seeds off of our box elder trees (Acer negundo), then disappear until the following year. During the entire winter this year, small groups of evening grosbeaks remained in our yard. I have no idea why. The FeederWatch project sponsored by the Cornell Laboratory of Ornithology did a statistical analysis of mid-winter evening grosbeak sightings compiled from 1999 to 2003 throughout the United States and noted a decline in the probability of seeing evening grosbeaks in many parts of the country. However, there were a few places where the probability of observing evening grosbeaks increased. Where Leonard and I live (Modoc County CA) the probability of sighting evening grosbeaks increased more than 5% – the highest increase on the probability map scale. Whether this general winter evening grosbeak decline in many areas is due to decreasing numbers of the species or a relocation of their wintering grounds is not known.
Anyhow, I have been able to observe evening grosbeaks and photograph them in my yard all winter. The male evening grosbeak has uniquely patterned plumage (golden brown body with bright yellow, white, brown and black markings), descriptions and pictures of which appear in an earlier post.
The female evening grosbeak is much duller, yet is striking in a more subtle manner. She is grey-brown above and buff on the underparts, collar and rump with a white throat. A faint yellow wash on the neck can be seen at the correct angle. A weak malar stripe goes from the base of the bill downward. The black wings and tail are patched with white. The black and white wing and tail pattern from behind is, in my opinion, beautiful. These evening grosbeak ladies can hold their own against the flashier males.
Leonard and I would be delighted if this stocky, finch decided to remain in our yard yearlong.