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Sunday, February 10, 2013

Seeing things through birds' eyes is very different


 It certainly looks a lot different. Besides seeing all the colors of the rainbow, scientists tell us that many birds can see into the ultra-violet spectrum, too. (as a kid I learned that the rainbow is “Red, Orange, Yellow, Green, Blue, Indigo, Violet”.  So birds can see what’s beyond violet.)
That's lots more than colors of a rainbow.
Painted Bunting (female)
Birdwatchers of all abilities often have difficulty telling male birds apart from females of the same species. However, research using ultraviolet light shows that males and females frequently have radically different markings that we can’t see. An example from north Texas is the Painted Bunting. The female Painted Bunting is very drab-looking to most mammals (potential predators);  unlike the bright red, blue and green male. (In many bird species females are similarly drab).  This drabness helps them stay hidden while on the nest - important to survival of the species.

Additionally, ultraviolet vision can also help birds in finding food. Research with Kestrels has shown that they can see trails of rodent urine; known to reflect ultraviolet light.

For years, many birdwatchers have put various objects including decals and feathers on windows to help prevent bird collisions. Now that we know about birds’ ability to see ultraviolet light, removable stickers have been created that are almost invisible to humans, but reflect ultraviolet light that birds can see, warning them.

 The Migratory Tourist   The Barn Swallow is on its way back to north Texas – a few may even be here as you read this!  It’s the only bird found here that’s been seen in every single South American country. The bulk of them spend the winter in an area centered roughly on Bolivia and Paraguay.  But this cousin of the Purple Martin (also a species of swallow) has spent winters as far north as Costa Rica, and as far south as Tierra del Fuego.

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