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May 19, 2012 / Leslie

Weekend Birding: Brown-headed Cowbird

This is a juvenile Brown-headed Cowbird who was raised by a pair of cardinals. Yes, cardinals. They adopted this little guy, but not intentionally.

Juvenile Cowbird

Although the Brown-headed Cowbird is native to North America, many people consider them a nuisance bird. They can be found in open fields, parks and backyards. They will show up at feeders, although no one I know puts out seed to attract them. They are noisy birds and the male makes a whistling or chattering sound.

Male Brown-headed Cowbird

Male Cowbird

Cowbirds are brood parasites. They do not build their own nests or raise their young. Instead, the female will lay eggs in the nests of other species and then remove one of the eggs of the host bird. Some host species eject the unwanted egg but most birds don’t notice and will raise the cowbird as their own.

Interesting Facts:

  • Cowbirds are promiscuous, there is no pair bond. Males and females have several different mates within a single season.
  • Female Brown-headed Cowbird

    Female Cowbird

  • A female will lay up to 40 eggs in a season and spends her day searching for nests.
  • Cowbirds will lay eggs in the nests of more than 220 species of birds.
  • Cowbird eggs hatch faster than other species eggs, giving cowbird nestlings a head start in getting food from the parents.
  • It is theorized that cowbirds became parasitic because at one time they followed roving herds of bison and had no time to stop to nest.
  • Cowbirds do not “imprint” on their foster families and will join the flock of cowbirds once they are grown.

Saturday Snapshot is hosted by Alyce at At Home With Books. Visit her blog to see more great photos or add your own.

© 2012 Under My Apple Tree. All rights reserved.



Leave a Comment
  1. Eugenia O'Neal / May 19 2012 6:18 am

    Wow! This bird doesn’t seem to have a single redeeming quality. The Bad Seed of the avian world!


  2. Louise / May 19 2012 6:54 am

    As this post came up on my screen I could just see the name of the bird, it was completely new to me and I was wondering what on earth this bird would look like, I must say that I was imaginging something much more exotic. The male looks like two birds stuck together doesn’t it? The information you’ve included about them is fascinating too. And I find it quite astonishing that they can switch of imprinting. I thought that was hardwired for birds…


    • Leslie / May 19 2012 9:08 am

      Apparently being a Cowbird is a genetic trait for these birds. They just ‘know’ their call (they don’t have a song), while other birds need to learn it. They also somehow know they are cowbirds and eventually join the flock.


  3. kaye / May 19 2012 8:01 am

    Wow, that’s amazing!


  4. Diane@BibliophilebytheSea / May 19 2012 8:33 am

    Don’t think I’ve ever seen a male cowbird. Your amazing bird shots never disappoint. well done once again.


    • Leslie / May 19 2012 9:09 am

      You probably have, they tend to blend into the background. At my bird walk last week I was the only one who wrote down seeing a cowbird. The others saw them but figured someone else noted them. And cowbirds are not anyone’s favorite bird.


  5. BermudaOnion / May 19 2012 8:38 am

    I always look forward to your weekend birding posts. The cowbird is fascinating. I don’t know if I’ve ever noticed a male.


    • Leslie / May 19 2012 9:09 am

      From a distance they look like a blackbird or grackle so they tend to go unnoticed.


  6. Marie / May 19 2012 8:51 am

    Great photos! I seriously dislike cowbirds. I chase them away whenever I see them and remove any food I see them eating.

    Last year, we had an Eastern Phoebe nesting over our deck. A cowbird came along and deposited her egg there. The phoebes raised it. The Phoebes tried again later that year, but were unsuccessful. All of the eggs were damaged. I can’t be sure, but it could have been the cowbirds trying to invade the nest again. It was heartbreaking that they never got to raise one of their own.

    We consulted a bird expert in the area. She told us that the cowbirds also come back to the nest after the egg is laid to check to make sure the egg hasn’t been removed or damaged. The worst thing she told us was that the adult Phoebes could become exhausted (and even die) trying to feed a bird that has a much bigger appetite than one of their young would have.

    So sad.


    • Leslie / May 19 2012 9:18 am

      Last year the cowbirds in my yard were putting eggs in a cardinal nest. I never found the cardinal nest but with both clutches I saw the male at my feeders with fledgling cardinals and a big old cowbird that I started calling Baby Huey.

      I’ve also been told that if the egg is removed the cowbird will lay another one. Last year I watched a Phoebe nestcam and the Phoebes raised one cowbird and two phoebes. We were so relieved when that big cowbird fledged… it was ravenous and grew like a weed!


  7. mostraum / May 19 2012 9:14 am

    Wonderful photos again. I’ve never heard of cowbirds before. Thanks for sharing all the info. Love the way nature works 🙂


  8. epkwrsmith / May 19 2012 10:00 am

    very interesting trivia…I’ve never heard of this bird…which is weird since I’m in rural MS with lots of cows!


    • Leslie / May 19 2012 11:30 am

      They tend to blend in to the background. Check out the sound they make and you might recognize it.


  9. Leeswammes / May 19 2012 10:14 am

    I never heard of this bird but it doesn’t surprise me it’s such a nuisance. If they don’t raise their own young they can have lots of eggs each year. Handy!


    • Leslie / May 19 2012 10:41 am

      Yes, they get the bad parenting award!


  10. Nise' (Under the Boardwalk) / May 19 2012 10:30 am

    This post was so informative! I have a nest with an odd looking egg in it, wonder if it is victim to a cowbird?


    • Leslie / May 19 2012 10:36 am

      I think you have a cowbird egg in that nest. You’ll know for sure when it hatches… they are big and hungry.


  11. Nan / May 19 2012 10:36 am

    I just loved reading all this. We’ve had them here occasionally over the years. I remember seeing them ride along on our horse’s back out in the pasture. I’m fond of them, despite their bad reputation. :<)


    • Leslie / May 19 2012 10:40 am

      It’s not really the bird’s fault that they are now considered a nuisance. I’m pretty sure I read somewhere that they eat the bugs off the cattle and horses, but as they lose their habitat they have had to adapt. So now we get them at backyard feeders and they put their eggs in little song nests.


  12. laurelrainsnow / May 19 2012 10:44 am

    Interesting facts…they do sound like nuisances, but they have their story, too. Thanks for sharing…and for visiting my blog.


    • Leslie / May 19 2012 11:28 am

      They aren’t bad as far as backyard birds go but they are a terrible nuisance for the smaller songbirds like warblers and some of the endangered species.


  13. Amy / May 19 2012 11:16 am

    How fascinating! Nature really is amazing. I wonder why these birds, cowbirds, in particular behave in such a way?! Hmmm…. I don’t know what surprises me more…that the female cowbird drops her eggs in other bird’s nests or that the other birds don’t notice the ‘foreign’ egg most of the time!

    Thank you for this info, Leslie!


    • Leslie / May 19 2012 11:22 am

      Not noticing the egg is one thing, but when it hatches and starts growing it looks nothing like its siblings and often is twice the size, and a different color, and still the parent doesn’t notice. Some birds do notice and get into a battle with cowbird tossing out its egg only to find the cowbird returned and destroyed their eggs. Fascinating indeed!


  14. Amy Peveto (@AmyPeveto) / May 19 2012 12:29 pm

    In other words, not someone you’d want to spend much time with. I do think they’re pretty, though. 🙂

    Here’s my Saturday Snapshot. Happy weekend!


  15. edgar / May 19 2012 1:33 pm

    The nuisance bird from survival of the fittest.
    There is really nothing good with cowbirds?
    Very nice photos.


    • Leslie / May 20 2012 9:07 am

      Cowbirds don’t appeal to very many people. They get the bad parenting award!


  16. Alyce (@AtHomeWithBooks) / May 19 2012 2:46 pm

    Very interesting information – I would have had no idea those birds did that!


  17. cherylmahoney / May 19 2012 5:15 pm

    That is so fascinating about the lifestyle of cowbirds… They don’t align at all with human values, but…is it fair to judge them by our values anyway? Really interesting!


    • Leslie / May 20 2012 9:12 am

      Their lack of “morals” doesn’t endear them to too many people… but true, that’s not really fair. The real problem is when their eggs survive at the expense of endangered song birds. As far as I know cowbirds are in no way a threatened species but some of the little songbirds they leave their offspring with are.


  18. irene / May 19 2012 6:57 pm

    This is so amazing. I think they are very resourceful.


  19. Bev@My Reader's Block / May 19 2012 7:24 pm

    Love reading about the Cowbirds. I was familiar with them, but not as much as I am now! I imagine the reason the birds don’t pair bond is because they don’t raise their own young–or maybe vice versa. Great pictures, as always!

    Here’s my Snapshot


    • Leslie / May 20 2012 9:37 am

      I think it’s because they don’t raise the young. It takes two parents to feed and fledge a nest of babies. Although last year I had a nest of wrens and the male was worthless. All he did was sing while the mom did most of the work. I was referring to her as a single parent! I think I saw him bring all of two bugs to that nest of babies.


  20. Paulita / May 20 2012 10:31 am

    Now that I have teenagers, I understand why the cowbirds choose someone else to take care of the raising for them. Here’s Mine



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