Tuesday, November 13, 2007

BLUE JAYS ARE NOT BLUE—

Birds look colorful to us for two reasons: 1) the color we see is actually produced by colorful pigment in the bird’s feathers, or 2) the color is produced by the feathers reflecting daylight.

The Northern Cardinal is quite red, of course. If a cardinal’s red feather was ground into powder, the powder would be red.

Not so with the blue jay, or any other “blue” bird for that matter. No pigment turns feathers blue.

In the photos to the right that is the same blue jay feather. In the top picture the feather is being held so it reflects daylight and it appears blue.

But, when I turn the feather so light is passing through the feather from behind, the feather appears a dull gray, which it is and which is the color you would find if you ground this feather into powder.

Try the same visual experiment with a cardinal feather and it will appear red regardless of the viewing angle.

If you are really curious about the finer details of this phenomenon, here’s an interesting source:


http://www.birdersworld.com/brd/default.aspx?c=a&id=667

1 comment:

TJ Wolf said...

Wow. I never knew that. Thanks!