Autumn is Here; questions on birds behaviors.

I was curious when I was watching two of my nest boxes were being explored by birds that have been going in and out of them today. As if they were nesting in the spring. Do they have a Fall's brood, or are they just shopping a safe place to roost for the winter to come? Please share your experience with me and others who may be interested in this particular behavior.

This particular birdhouse, was throroughly checked out by blue birds earlier in the Spring. But was not occupied by any. Today, I believe this-- maybe Titmouse that coming in and out of the house.

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Ooops, wrong pix above. This is the one.

Then, this birdhouse was occupied by a pair of White-breasted Nuthatch in the Spring. Maybe the same pair have returned? I've seen WBNHs visited this same birdhouse during the summer every so often. But this couple was really intense checking out the nest box today. Notice; the temperature has dropped suddenly to 39F. degrees from the mid. 60'ish during the nights this past week.

Then once again, the Nuthatch was there, first thing this morning before it came to feed.

Probably just checking out potential roost sites for when the bad weather comes. They wouldn't be raising a new brood now.

Resin

Thank you Resin, I suspected that was what they were doing. But I wasn't quite sure. Smart little birds, aren't they?

Temp. has really cool down in this part of the region. My White Breasted Nuthatchs pair are seen checking the bird house out once again.