My favourite parasite?


To continue on my “bird photo blitz” to honour Vancouver’s Bird Week 2014, I will feature a much-maligned species, the Brown-headed Cowbird (BHCO). This bird gets a bad rap among birders and other people in the know, because it practices “brood parasitism.” To put it another way, they lay their eggs in the nest of another bird species and let the other parents raise their young. Evolutionary biologists believe this behaviour evolved to allow these birds to follow the huge herds of bisons that used to roam the North American plains, without having to worry about raising their young.

I should also point out that they often target much smaller species, including warblers. To see the colour of a BHCO egg, take a look at this picture on Wikipedia. And to see the sometimes surprising size difference of the “chosen” species, take a look at this Yellow Warbler feeding a young BHCO – posted in Murr Brewster‘s wonderful blog.

Having said all that, as the following photo can attest, the male of the species can be quite striking and even beautiful, especially in early spring, when the contrast between its brown head and black body becomes even more striking due to the iridescence its black feathers, which make them seem deep turquoise in the right light. I took this photo along the boardwalk (Piper Spit) in Burnaby Lake Regional Nature Park.



3 thoughts on “My favourite parasite?

  1. Thanks Pierre,sharing your great photos and educating us about my feathered friends at the same time. Lise Brayham

    Sent from my iPad


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