Sometimes when I point out a Cowbird, someone remarks with distain “Oh. One of those!” They have a bad reputation.
Female Cowbirds lay their eggs in the nest of other bird species. The Cowbird has been known to parasitize over 220 different species of North American birds.
There are many photos on-line:
Why do they do this? Here is information from the Cornell Lab. of Ornithology:
Historically Cowbirds followed herds of bison, eating insects kicked up by the animals’ hooves. It is unknown whether they developed their breeding strategy because they had to move frequently to keep up with the bison herds, or whether they were able to follow the herds because their breeding strategy gave them the freedom to do so.
Both morning and afternoon groups saw Cowbirds today at Beechwood / Don Valley.
10 am group:
1 pm group:
Calm was the even, and clear was the sky,
And the new budding flowers did spring,
When all alone went Amyntas and I
To hear the sweet nightingale sing. – John Dryden (1631–1700)