Well, last week I personally evicted at least 1 squirrel. Hollow branch over some service drops and a driveway... bombed the tip out and the squirrel ran away like a little grey blur, so I guess it was fine.
A few years ago I was working with a friend taking down a rotten black birch. Got the tree down no problems, but when my friend was going to cut the stump lower we found a baby squirrel in there trying to get out. The home owner wanted us to kill it with the chainsaw, but we re-located it someplace else on the property. Same thing happened about a year ago on one of my jobs... taking down a rotten sugar maple at a friend's house. Cutting the stump lower I see some movement in the rotten part. I called my friend over and she rescued a little baby field mouse out of there... she tried to nurse it back to health in order to release it into the wild.
Stuff happens, and sometimes it can't be avoided. However if there's a chance to save another creature's life, particularly a baby creature... I think we owe it to that animal to give it a helping hand... I mean we're the ones who are taking away their homes. Not like they are driving up to ours in bulldozers, or selling us adjustable rate mortgages.