Monday Mystery: Name that Nest!
Bright Lights, Big Death Trap

Monday Mystery Part II

A fellow Bergen County bird lover writes:

Can you explain why the sparrows in my yard are going into my birdhouses?

There are usually two of them, one enters the birdhouse and stays for up to one minute and then they both fly away.

I see this activity during the spring mating season, but now it’s mid-October ....

I have a theory, based on Eastern Bluebird behavior. What do you think?