I had occasion to be up for the dawn chorus (plays daily, check local listings for times at a location near you!) the last two mornings. The two mornings seemed distinctly different, though in each case I heard the first calls somewhat before 3am and the intensity seemed to be greatest shortly before 4am.
Yesterday the skies were clear, and it never got fully dark in the north. By 2:30 or so the sky was showing the first signs of increasing light. Hermit Thrushes started with a single note whistle (that’s fairly easy to imitate) as they woke up. By 3am they were singing their full song. I could hear several of them both near and far. Shortly afterward Robins woke up and started singing, joined also by a few Swainson’s Thrushes. (The latter are one of the last species to arrive in the spring, and they’re just now getting started setting up for a summer of nesting.) Over the next half an hour, these species were joined by the relatively late rising Varied Thrush, and finally I also heard Winter Wrens, Townsend’s Warblers, Chestnut-backed Chickadees with an occasional Wilson’s Warbler.
This morning it was overcast, and the night was a bit darker. During the night I heard a Western Screech Owl calling a couple of different times, something I did not hear the night before. As 3am approached the sky was getting lighter, and once again I heard the chirps of Hermit Thrushes. However, unlike yesterday, they didn’t really seem to start singing this morning. Finally, well after I had heard the first Hermit Thrush call notes, a nearby Robin woke up with an alarm and then started into its song. Soon it was joined by many others. I did hear a few Hermit Thrush songs in the midst, but nothing like the previous morning. Once again, the Varied Thrushes joined in later, followed by the Winter Wrens and Townsend’s Warblers. I did not notice chickadees this morning, but I did hear Ruby-crowned Kinglets later in the morning.
I’m a little curious about the differences, in particular the singing activity of the thrushes. I wonder if the overcast skies had something to do with it. If I can muster the motivation/discipline, I’ll try to listen a few more mornings and take some more careful notes about what I’m hearing and when.