North American dark-eyed junco evolution

This is a dark-eyed junco video from Canada.

Snowbirds Skip Migration, Setting Off a Cascade of Changes: By and large, Dark-eyed Juncos live up north and visit the rest of the continent in winter—they’re “snowbirds.” But around 1980, a few pairs in San Diego decided to skip the trip north. This is the story of what happened next: the birds quickly adapted their plumage, song, and nesting behavior, forcing scientists to rethink ideas about the speed of evolution: here.