Feb 22 2013
The scarlet ibis looks bright orange-red to us but that’s not what the ibis sees.
Unlike humans, birds can see ultraviolet light. This trait was discovered by accident and largely ignored until we figured out that most birds have ultraviolet-reflectant feathers. This opened up a whole new view of plumage.
Above is my poor attempt at showing what this looks like. Instead of orange-red the ibis appears purplish to himself and other birds — more purple than I can show. For an awesome photo of what birds actually look like click here and scroll down to see three views of a cockatiel.
When the ultraviolet colors came to light we uncovered many surprises. The axillary feathers of northern saw-whet owls are UV-reflectant. Who knew their armpits were so flashy! The brightness fades in older feathers so bird banders use UV light to age the owls. Here’s a saw-whet UV photo linked from Washington College’s Chester River Field Research Center where they band the owls. (Click on the photo to read more.)
The world of birds is far more colorful than we imagine.
A scarlet ibis does not look scarlet to an ibis. Really.
Scarlet ibis photo by tj on Wikimedia Commons, retouched by Kate St. John to attempt ultraviolet shades. Click on the image to see the original.
Northern saw-whet UV axillary feathering by Washington College, Chesterfield River Research Center, Northern saw-whet monitoring.
Today’s Tenth Page is inspired by page 100 of Ornithology by Frank B. Gill.)