Sunday, May 04, 2008

Not so awful, after all

Cowbird, male.

Until our recent visit to Reifel Island, I had never seen a cowbird up close. Laurie pointed them out to me, occasionally; little black birds off in the distance, indistinguishable, as far as I could tell, from the starlings.

I had read about them, of course. Cowbirds are those nasty parasites that lay their eggs in other birds' nests, leaving the poor foster parents to do all the work. Worse, the greedy youngsters, hatching first, get all the food and the other occupants of the nest die. That's if the cowbird chick hasn't pushed them out of the nest already.

Just plain bad.

Now that I've seen some, Googled them, and learned a bit more, I've changed my mind about them.

Speaking his mind.

Cowbirds got their name because they hang out around cattle, eating the insects that plague cows and horses; bot flies, horseflies, ticks, etc. If I owned a few cows, I'd want to have a flock of cowbirds on hand.

And their "nasty" trait of letting other birds raise their young? It is suggested that, before the continent was "civilized", when bison roamed the plains and cowbirds took care of them, they stayed with their ranging food source. If they had stopped behind to tend nests, they would have lost contact with the herd and starved. So they laid their eggs and flew away. Today, most of our cattle are confined behind fences, and the need to move on no longer applies, but the pattern is set.

And, so it seems, the harm done to the other birds is not great. Studies show that as few as 3% of the cowbird eggs actually hatch. Most are recognized by the host species, dumped from the nest, broken, or abandoned. Sometimes the chosen foster parents just build another nest on top of the old one containing the cowbird egg.

Many of the foster parents, besides, seem to be stimulated by rearing a cowbird chick and start a new batch of their own; they are often more successful at raising their own families than non-parasitized birds. (See Audubon; Cowbirds and Conservation.)

That's nice to know.

Mallard and cowbirds; these are small birds. Or the duck is big. Take your pick.

I noticed, going over my photos, that all of the birds are male. The females are a plain grey-brown, and none of my little brown bird photos match the cowbird females.


  1. Hmmmm .... logically, I agree. Emotionally, I don't think I'll ever warm up to cowbirds. I do like that last picture with the mallard.

  2. Interesting info! I may be a little more forgiving of them in future. We get cowbirds here and they come to the feeders ... but not yet.

    Amazing, the info we can access on the internet!

  3. Glad to see this! Funny you should post about it, I have some photos from a couple weeks ago tucked away in my files for some future post on the same subject. I do think that the cowbirds are something of scapegoats, painted to be evil birds destroying populations of unsuspecting species. It's easier to do that than to paint ourselves that way; the cowbirds are simply a symptom of a greater human-created problem.

  4. Wren; Yes, emotionally, the very idea of making other birds raise their young is off-putting.

    Cis; It is amazing! Any question that comes to mind has an answer at the tip of your mouse!

    Seabrooke; Great minds, and all that. I will be looking for your post on cowbirds. I think you're right about the scapegoat idea.

  5. Interesting, that they followed the bison. Now, I'll be looking for cowbirds on the ranch I visit for bird photography.

  6. Hi WW - I'm visiting you through I and the Bird #75. I enjoyed reading your post. I posted about a cowbird visiting my feeder a few weeks ago. This was the first time I've seen a cowbird in my yard. Then last week I saw the female for the first time, but alas, no photo of the female.

  7. Hi, Mary,

    That's a good cowbird photo you have.

    And I had to laugh; your most recent post puts a nice, "kind" spring at 75 degrees. And we were glad, recently, that it was no longer freezing at night!

    Too bad about your poppies, though.

  8. I passed this on to a friend who's been complaining that too many cowbirds are showing up at his feeders.

    I'm sure there are some around me but I don't notice them much.


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