Normally occupied in winter by a few creeping nuthatches, the elm in our yard today is hosting a big party of bohemian waxwings. (Yes, this species has one of the great bird names.)

Being an erstwhile birdwatcher, I mistook them at first for cedar waxwings. (Exciting enough; I hadn't seen those in ages.) But these birds have russet undertail feathers.

Hence, we're hosting a bohemian rhapsody. What, you thought I wouldn't mention that tune? Here's a sample of what this rhapsody sounds like -- a continuous, squee-pitched trill, before the flock takes flight:

http://www.youtube.com/watch?v=DpaECBRpIMo

But why would birds flock in a migratory way in the deep mid-winter? It's -15ºC today, and the sun has barely peeked over the horizon. According to our trusty Audubon Field Guide:

This species forms large winter flocks ... only about once a decade. Its occasional erratic movements southward in winter are thought to be caused by food shortages in the North. (682)

I'll say. They're chowing down on all the mountain ash berries that are still clinging to the trees. So that's who eats them. I was starting to think mountain ash berries are the brussel sprouts of the bird world.