For the most part, the cedar shavings that we used to “winterize” the bird nest boxes have done their job: They’ve helped to plug up any joints in the wood walls, have likely given the birds some needed insulation, and most importantly, gave them something to do.
Almost immediately, we noticed that the European Starlings started removing portions of the cedar shavings. This behavior is similar to what we see during nesting season: The male puts nesting material in the box, and when he attracts a female, she promptly removes everything inside (to redecorate, we assume).
The shavings are also dropped around the outside of the nest, which helps us identify if a nest is actively being used or not. While they tolerate flash photography while in their nest at night, it’s certainly not something without a degree of stress for them.
Also, you can see the indentation in the far back of where the bird(s) end up nesting, almost to the bare floor, yet surrounded by the cedar shavings in their nest.
All in all, we’ve been pleasantly surprised at how fast and how consistently the nests have been used this winter. It’s new behavior, although to be fair, we’ve never had new nests up this late in the cold season before.