About us: We own the Wild Birds Unlimited nature shop in East Lansing, Michigan,
a store that provides a wide variety of supplies to help you enjoy the birdwatching hobby.

This blog was created to answer frequently asked questions & to share nature stories and photographs.
To contribute, email me at bloubird@gmail.com.

Wednesday, May 10, 2017

Are cowbirds a concern

Adult female Common Yellowthroat feeding a recently fledged Brown-headed Cowbird
I would say humans are more of a concern to the decline in the number of certain birds. As we fragment up the forests to develop the land, we create more nesting territory for Brown-headed Cowbirds. This also creates more nesting areas for European Starlings, House Sparrows and some other more favored birds like the American Robins and Northern Cardinals.

But cowbirds have attitude and are very smart. When I'm filling the feeder they hang around seemingly unconcerned. But they are always watching. They watch the other birds feeding and can even follow these other birds to their home and lay an egg in their nest.

Cowbirds are parasitic birds. They may lay up to 40 eggs per season in many other birds nests and expect those birds to foster their cowbird chick to maturity.

Where this is a concern is with warblers that have a hard enough time finding a dense forest to nest in without having to worry about raising an extra fledgling that usually hatches earlier than their own eggs and can be twice as big.

Cowbird control in the northern Lower Peninsula of Michigan is believed widely to have saved the Kirtland’s Warbler from extinction and to have played a key role in population increases in the past 15 years. However, there was no growth in the warbler’s population for the first 17 years of cowbird control, and a large fire that preceded the recent population increase may instead have been the primary benefactor of the Kirtland’s Warbler.

Related Articles:
- How Do Cowbirds Learn to Sing? http://goo.gl/Y9HNDM
- How young cowbirds know they're cowbirds http://goo.gl/Jgmavd
- More about Cowbirds http://goo.gl/b1PkOd
- If cowbirds were in the summer Olympics http://goo.gl/Rajjtf

- Brown-headed Cowbird's courtship display http:/brown-headed-cowbirds-courtship.html 

1 comment:

Anonymous said...

Humans! The power company is taking down way to many trees in East Lansing to prevent a tree from falling on a wire. What about the birds, squirrels, etc that live and nest in those trees? A shame!