Oct 02 2009

Eyes in the back of her head

Published by at 7:26 am under Songbirds

American Goldfinch (photo by Sam Leinhardt)

Sometimes you can't see a bird's traits until they're frozen in a photograph.

Look closely at this American goldfinch browsing on Sam Leinhardt's zinnias.  Even though only the top of her head is visible you can see both of her eyes. 

Goldfinches are small birds about 4.5 inches long.  At this size they are easy prey for owls, cats and hawks so they have to be wary.  What better way to be prepared than to have peripheral vision above and behind so you can see danger coming, even when your head is down feeding on seeds. 

Many small birds have this trait, but how did they get it?  Indirectly, from the relentless pressure of predators.  Goldfinches who couldn't see danger coming were easy prey while those with wide peripheral vision survived.  The survivors had "kids" with the same trait.

So, yes, she really does have eyes in the back of her head, just like all her relatives.

(photo by Sam Leinhardt)

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