Occupied

 

Day 180: A very strong biological imperative must have been at play here, because the House of Chirp already has renters. The first Tree Swallows to arrive acted as if they were already a mated pair, flying together consistently with wingtips almost touching. They perched on the phone wires together, and both showed interest in the "apartment." I saw the female at the door several times, but did not observe her carrying nesting material, however within a week of the time I had seen the birds initially, she had moved inside and was establishing housekeeping. It is hard to tell the male from his partner unless the light is perfect, but I believe he has been helping with the moving-in. Tachycineta bicolor typically lays a clutch of 4-6 white eggs and incubates them for roughly 13-16 days from the time the last one is laid. Young will leave the nest 16-24 days from hatching. Although not common, sometimes the pair will produce a second brood in a season.