Singing all Night?! Don Kroodsma’s Research
Below are two graphs that I find ultra-intriguing.
First graph.
In the first are graphed the number of songs/minute during 18 hours, from 9 hours before sunrise to 9 hours after sunrise.
Songs were totaled for 5 minute periods, then divided by 5, so “songs/minute” are plotted for 5-minute periods.
Sunrise 5:18am. Begin recording 8:22 p.m., with sunset 34 minutes later, at 8:56pm. Stop recording at 2:18 p.m.
Admiral Road, Sax-Zim Bog, Minnesota, May 29-30, 2016.
Second graph.
A second Connecticut Warbler. Begin recording 7:38p.m. on 5/29, end at 10:13am on 5:30.
Owl Ave, Sax-Zim Bog, Minnesota, May 29-30, 2016 (same date)
What’s this night singing all about?
Any male warbler who sings all day long is unpaired. It’s my guess that when these Connecticut warblers sing all day long, they’ll also be singing all night long. And when they stop singing during the day, they’ll stop singing at night. So I would guess that the night singing is all about attracting a female. (Then why don’t more birds do this? Wish I knew! Unpaired mockingbirds sing at night. And a few other species . . . but nothing really like the energy of a CT warbler, I don’t think.)