Bluebirds through the window

I've been observing bluebirds out my window. They arrive in small flocks of 6 - 10. They flutter about the yard, trying out different perches, nabbing a wayward insect or two, and then they begin to land on the nest boxes. It's fun to watch them as they check out the boxes. I can easily anthropomorphise their behavior as they flick their wings and chatter to each other: "What do ya think? I dunno, let me go in...Please do! After you..Thank you,Yes, okay, this one's not bad.." and so on. In fact, I can imagine them chatting back and forth in the manner of those polite gophers from the old Looney Tunes cartoons. But I digress.
In the winter months, bluebirds form small flocks and travel about foraging together. They will use empty nest boxes as a communal roost at night when the temperatures really plunge - as they tend to do during our long, dark Pennsylvania winters. I like to think of these as 'our' birds, although there's no way to know for sure if they are, in fact, birds fledged from our nest boxes.

Looks like they're trying to reach a consensus.

 

Wing-flicking - "Over here, this one looks great!"

Some background info would be helpful.We put up the nest boxes years ago, as we live in ideal bluebird habitat: open fields bordered by woodlots. We've hosted nesting bluebirds every year since. They always raise two, sometimes three, broods. We love 'our' bluebirds! They are very personable - as birds go - and beneficial to have around the yard since they feed on insects, caterpillars, and the like.

Our first two nest boxes were mounted on a fence post and a tree. Both are terrible ideas. It's amazing how many different creatures can and will climb in order to reach a tasty meal of eggs or nestlings.The final straw came when a squirrel deftly reached into the tree-mounted box, pulled out the nestlings one by one, and devoured them. Murdering squirrels?? Waaah! Enter our current predator-proof mounts.The boxes are on metal poles with a homemade predator guard below.
 Resourceful humans - 1
 Pesky squirrels, cats, raccoons, snakes, and other assorted climbing critters - 0

If you plan to host bluebirds, do yourself a favor and install the boxes on a metal pole with a guard underneath. Here are plans for a stovepipe baffle. That website, Sialis.org, is an excellent and complete resource on being a landlord to bluebirds and other native cavity nesting birds. I might mention that I didn't touch on the subject of English Sparrows here - that is a subject for another day when I'm in more of a ranting mood. Suffice it to say that the predator baffles don't help with that problem. And problem it is, with a capital P which rhymes with G and that stands for Gun.... Stop right there! Before you write me off as a yee-hawin' nut - hear me out. I am not a shoeless, gun-totin' old Ma with a chaw in m' lip - if you peruse the Sialis website, you'll see where I'm coming from and what a dire threat the sparrows pose to Bluebirds.

Meanwhile, off I go to waste some more time, staring out the window at the cute antics of MY bluebirds!