European Starlings change their appearance in winter. Gone is their colorful iridescence, replaced by white speckles on otherwise black plumage. Even their beaks change color from gray to yellow. I have seen flocks of Starlings large enough to darken the sky.
Starling flock is a mainstream, 5-7-5 haiku inspired by these interesting birds. Many birders chase them away, but they will always be welcome at my feeder.