Brown-headed cowbirds are courting now because their victims are about to nest. The males sing a bubbly whistling song to attract a favored female. After she’s chosen a mate, Mrs. Cowbird lays her eggs in the nests of smaller birds whose own eggs and nestlings die while the foster cowbird chick thrives.
In cowbird society nest building and incubation never occur so the pair bond is cemented by courtship songs and postures. Amazingly, the quality of the male’s song really matters. That’s how the female decides who to accept and who to ignore.
What happens if a female can’t tell the difference between good and bad songs? What happens when one lady in the flock doesn’t follow the rules? Last year scientists learned that one tone-deaf female can upset cowbird society.
Researchers at the University of Pennsylvania led by Sarah Maguire inactivated the song-control centers of some female cowbirds’ brains so they could no longer distinguish between high and low quality songs. When placed in a mixed-sex flock these ladies reacted to all songs and did not stay with a chosen male for long.
Since male dominance among cowbirds is based on song quality the best guys usually get the best gals. However, when a tone-deaf female appeared in the flock she listened to all males equally and the minor males got a boost. The dominant males courted the altered female more vigorously. The other ladies were left in the cold.
Which guy will she choose? One tone-deaf female can mess up an entire social structure.
This morning I heard the sound of a lonesome dove.
When seeking a mate male mourning doves call like the ones in this video. Those who’ve found true love don’t need to sing because the cooing is a solicitation call, not a territorial defense.
Unmated males perch-coo from the heights as loudly as they can, “Ladies, I’m available.” It’s amazingly loud considering they don’t even open their mouths. A few have already begun calling in my neighborhood but the peak time will be late April through June.
Males also use flap-glide flight to attract female attention. Taking off with exaggerated wing-claps, they fly up above the trees and rooftops, then spiral down with stiff wings held slightly below their bodies. From a distance their silhouettes resemble kestrels or sharp-shinned hawks. They’ve fooled me more than once. Here’s my attempt at what they look like, gliding from left to right:
Today sunrise is at 6:49am so a lot of us are awake before the perch-cooing begins, but lonesome doves can be annoying in June when they start calling at 5:00am.
Quiz! Test your “birding by ear” skills with this video. In addition to the mourning dove there are at least seven other species singing in the background. Who are they?
(video by Carl Gerhardt, musicofnature.org via YouTube. Silhouette drawing by Kate St. John)
I love classical music and often whistle the tunes, especially when I’m happy. Last Saturday afternoon was one of those days.
The weather was warm and overcast as I walked up Nine Mile Run from Duck Hollow to Frick Park. I was hoping to find a fox sparrow — no luck — but was pleased to see a beautiful male American kestrel and a flock of 40 robins. I found only three song sparrows on my way north.
When I reached the hillside grassland on my way back I remembered the Adagio from Mendelssohn’s Piano Concerto No. 2 and started whistling the piano solo.
Suddenly song sparrows came out of the underbrush. They flew through the weeds making little “bep” calls. I stopped walking and continued whistling. The sparrows kept coming, flying into the weed tufts. “Bep bep bep.”
I was making good progress through the piano solo though a little squeaky on the high notes because the piano has a wide range and I do not. Pretty soon seven song sparrows were perched on a sapling in front of me, five more on the weeds nearby and several more flying in to join them. This was in an area where I’d seen no sparrows on my way north.
At their peak I counted 15. The sparrows insisted on perching in front of me. All of them made warning calls. They seemed to be saying “Shut up!”
Perhaps they’d heard this good performance of the second movement and knew I was murdering the solo that begins at 0:40 in the video at this link.
I thought I did pretty well with a complex piece but I drove the sparrows wild!
(photo of a song sparrow by Bobby Greene.
music by Derek Han, Piano, Israel Chamber Orchestra, conducted by Stephen Gunzenhauser. Adagio from Piano Concerto No. 2, Opus 40, Felix Mendelssohn)
These four swans are really hooting it up. The quartet began when two pairs encouraged their mates with lean-forward and wing-quiver calls. But the quivering wing display is also used in antagonistic encounters. When the males got too close the dominant male had had enough. He rushed the other one.
Whoa! The less aggressive male immediately sat on the water in a submissive posture and the situation defused. Watch him curl his neck down in an S position and look away.
Tundra swans can make music together. Sometimes they jazz it up.
AND A QUIZ! Identify the other bird singing in the recording. His song is not normally heard in southwestern PA in the summer. The mourning dove lives year-round from Maine to Mexico, from Canada to Cuba. The other bird will give you a hint on the location of the recording.
(photo by Dori on Wikimedia Commons. Click on the image to see the original)
I’ve seen white-winged crossbills before, especially in the winter of 2009, but this year they’ve eluded me. People send news of them to PABIRDS but when I travel to their reported location they aren’t there. True to their irruptive nature crossbills are always on the move. Dang!
Last week I ran into Claire Staples while on my lunch break in Oakland. We exchanged bird sightings and Claire said she’d experienced the same problem finding crossbills until quite recently when she heard them near her home in Squirrel Hill.
The clue is their sound. Claire says they sound like typewriters, a useful tip as I actually do remember what typewriters sound like. Shows how old I am!
So now on my walks I’m trying hard not to look for crossbills as I don’t want to jinx my chances of seeing them. But I’m listening for the sound of typewriters.