The bluebirds are probably wondering why they came north when it keeps snowing in May but at least the snow has melted off the branches so they have a dry place to perch. Most years they would have their nest built and sitting on eggs by now but it has been rather chilly for that. I did see a pair of bluebirds checking out the birdhouses before the last snow.
The male Eastern Bluebird ‘shows off’ at his nest cavity to attract a female. He brings nest material to the hole, goes in and out, and waves his wings while perched above it. That is pretty much his contribution to nest building; only the female Eastern Bluebird builds the nest and incubates the eggs. But at least he does bring food to the babies so that the female doesn’t have to do all the work.
Chilly Bluebird