May 08 2014

Which One Should I Choose?

Published by at 7:15 am under Bird Behavior,Songbirds,Vocalizations

Trio of brown-headed cowbirds (photo by Dori from Wikimedia Commons)

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.

Read more here in PLOS One.


(photo from Wikimedia Commons, Creative Commons license.   Click on the image to see the original)


5 responses so far

5 Responses to “Which One Should I Choose?”

  1. Mom Teeon 08 May 2014 at 9:04 am

    I’ve always thought so!

  2. Kayon 08 May 2014 at 11:04 am

    Off the subject of cow birds – but there was another article in the TribLive yesterday about the rat infestation in Hazelwood. County officials are going to try a new poison that extracts calcium from the bones of the rats and deposits in their organs. The article said the poison won’t affect the eagles because their hollow bones don’t store calcium in the same way. The full article is on the TribLive website.

  3. Susanon 09 May 2014 at 11:12 pm

    I get groups of cow birds at my feeder at different times of the year. Once young birds fledge, do they then join up with other cow bird groups? I’m assuming they don’t stay with their “adopted” parents. I wonder how they know to repeat this behavior generation after generation, since the young birds live and grow up with other birds that don’t do this?

  4. Kate St. Johnon 09 May 2014 at 11:21 pm

    Susan, click here for the answer to “how cowbirds know they are cowbirds.”

  5. Susanon 10 May 2014 at 3:15 pm

    very helpful! It’s the Stellaluna of birds.

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