Saturday, March 16, 2013

Can you name a feeder bird in Michigan that is green?

One of the gardeners’ favorite birds is fairy green. You may remember the flash of red the male shows but most of the Ruby-throated Hummingbird is green.

Green is the first color most people think of when you talk about nature. So why are there so many brown birds? Green feathers would blend into the trees which are green all year-round like in tropical climates. But in Michigan brown and gray are the feather colors that actually make them harder for predators to see.

Our eyes allow us to see three primary colors in terms of light which are red, green and blue, but birds see a different colored world. Research has revealed the retinas of some birds are sensitive to light in the ultraviolet band, and seeing a broader spectrum of light can make as big a difference as watching black and white verses color television.

A spectrophotometer scan of songbird plumage where the birds are sexually monochromatic (males and females looking identical) like the cedar waxwings, titmice, chickadees and wrens, reveals they are actually sexually dichromatic (different once you take into account the colors including ultraviolet). To the birds themselves, males and females look quite different from one another.

In laboratory tests it was found that female birds preferred males with the brightest “invisible” plumage, perhaps proving that the UV- reflecting feather colors birds saw were very important.

Related Articles:
- A Birds-eye View: Are Hummingbirds Attracted to Red Feeders? http://goo.gl/Nyo6N
- How to Prevent Window Strikes during Migration with UV decals http://goo.gl/K7xRK
- Why Blue Jay feather really aren't blue http://bit.ly/roVPVX
- What can I feed the cardinals to make them redder? http://bit.ly/vn2HK3

References:
M. C. Stoddard, R. O. Prum. How colorful are birds? Evolution of the avian plumage color gamut. Behavioral Ecology, 2011; DOI: http://beheco.oxfordjournals.org/content/22/5/1042.full

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