Some days I won't see a bird at the feeders all day and then suddenly a flurry of them will arrive all at once. Several species have a tendency to travel in packs, and these mixed flocks will travel around in loose affiliation looking for food--be it in the form of feeders, berry bushes, seed-bearing grasses, or a hatch of flies. The advantage to this seemingly cooperative behavior is not so much altruism as the fact that more eyes can more efficiently find food and keep a look out for potential threats.
Birders on the prowl will listen for chickadees and then see what else is tagging along with these vocal, gregarious little birds. Or you might hear a birder imitate the whinnying call of a screech owl, which serves the purpose of drawing in chickadees--who hope to scold and harass the owl into leaving the area--and their tagalong cohorts. Sometimes these can be interesting warblers or sparrows passing through, or more often local residents like the downy woodpecker.
The flock that usually hits my feeders includes chickadees and titmice, and occasionally some goldfinches, a nuthatch or two, and maybe a cardinal. (I use the word "hits" deliberately, as the repetition of thumps as each bird lands on the feeder, one after another in quick succession, can sound like a minor assault on my windows.) Today's five-minute bird blast came in the form of several titmice, a few chickadees, and one female cardinal. The suddenness of this avian visitation shook me out of work mode for a few moments, forced a break in my routine as I watched to see who might show up. And then, as quickly as they appeared, they were all gone, moving on in the rain.
Fall rain falling fast.
Birds here, a feeding flurry,
then gone. Still, the rain.