Comment by jonathanyc

> In looking at roost networks of bank swallows in Ontario you can identify that, “Oh, some bank swallows at night are actually going to different roosts from where their babies are,” and the adults will often trade off. We don’t know why, but they will sort of wander around and travel a hundred or more kilometers to a different place between nights.

That is actually pretty surprising to me. The weirdest insight from animal trackers I’d previously heard was kind of similar—that wolves regularly travel a lot further than scientists would have expected—but trading off roosts is a whole different level.