Yesterday morning I stepped out on the front porch just after 6:00am to check the weather. It was my first morning home from Maine and I was a little surprised that the sun hadn’t come up yet. What was I thinking! Maine is so far east that the sun rises there 45 minutes earlier than it does in Pittsburgh. I had nearly an hour to wait for dawn.
As I gazed at the waning moon I heard a sound like spring peepers coming from above. I knew the distinct solo “peeps” were the nocturnal flight calls of migrating thrushes, but which ones?
The pre-dawn sky was clear with a light wind from the north. The birds kept coming with hardly a pause. I rushed indoors to get my binoculars but it was too dark to see the birds. In my excitement I forgot to count the sounds so all I can tell you is that they passed by steadily for 20 minutes. My guess is there were several hundred of them.
Later indoors, I listened to recordings of nocturnal flight calls. I couldn’t find any audio examples – only voice-prints – but I looked through descriptions of various thrushes’ calls and found this at the All About Birds description of the Swainson’s thrush: “Nocturnal flight call a “peep” similar to a single note from a spring peeper frog.”
So that’s who they were.
I heard Swainson’s thrushes migrating this morning as well. I wish I could have seen them.
(photo by Chuck Tague)
Kate, I don’t understand what you would be doing by counting the sounds. Is that a way to count the number of birds?
Counting the sounds sort of counts the birds. Granted, I can’t figure out which bird is making which sound in the dark but if I estimate that I am hearing two “peeps” from the same bird before it passes out of hearing then dividing the count by two would give me the number of birds. I don’t know the ratio so my calculation would be inaccurate but Cornell has published a study on it: http://www.birds.cornell.edu/brp/research/nocturnal-migrant-flight-call-research
Very, very interesting. Thank you.
Heard the call in the woods in a campsite in Brewster, MA in the AM during breakfast Oct 21st. Spread out around the campsite, mostly seeming to come from on or near the ground. Lots of fat Va Creeper berries about. Maybe they were stoking up on those. By about 10:30 AM the calls became less frequent.
Chaffee, sometimes the sound really *is* spring peepers. They peep in the fall when it’s warm … but only when it’s warm.