They are not suppose to be here. Look at most field guides and that's what they will tell you. Eastern Bluebirds migrate south for the winter and are not commonly found in Minnesota. I'm sure there's always a straggler or two that might attempt to overwinter, but normally they are not found here during the winter. But I wonder if the books should be changed?
For at least the past 5 years or so there have been many Eastern Bluebirds overwintering here in far SE Minnesota—at least in our neighborhood. (Near Hokah, MN)
But how do they survive? They're insect eaters aren't they? During the warm months, they eat bugs and worms, but at least here during the winter I have watched them feed on sumac seeds and hackberries. And...freeze-dried meal worms from "Al's Diner."
This winter I have been feeding them a lot. This extremely cold winter has temperatures falling well below zero (F) on most nights. This is got to be tough on them. I keep hoping we'll break the back of winter soon so I don't have to keep worrying about their survival.
One thing I want to make perfectly clear. I do not feed them once nesting season is over. They are on their own. I had hoped this autumn they would have the common sense to migrate south, but such was not the case. I finally gave in and started feeding them again in mid-December since I knew they weren't leaving.
So now here it is early February and they are still here. On the really cold days, I'll find up to eight Eastern Bluebirds at the meal worm feeder. Usually a few in the morning, then more towards sunset. They seem to want to stock up on calories before they roost for the night.
Regarding the subject of roosting, you may or not have seen the video I did a few years back of the bluebirds co-habitating in a nest box for the night. If you haven't had a chance to see it, it's quite amazing to watch. Here's a link to the video via YouTube:
Here are a few images that I have taken of these poor guys this winter:
NOTE: If you know of any other areas where Eastern Bluebirds are overwintering in Minnesota, please contact me. Thanks!