Biology Reference
In-Depth Information
Q Is there a topic that teaches how to identify feathers?
A
No. Some birds, such as flickers and Blue Jays, have many easily recognized feathers,
and some birds have at least a few easy ones. For example, Cedar Waxwing tail feathers
are each tipped at the terminal end with a brilliant band of yellow, and Eastern Kingbird
tail feathers are tipped with white. But identifying most individual feathers is not nearly
that straightforward.
Most owl flight feathers are extremely soft, as if coated with velvet, and their leading
primary wing feathers have a stiff “comb” on the leading edge. But it's tricky to know
which owl a given feather might have come from, though size gives some hints. Ducks,
shorebirds, and some other water birds have outer feathers that feel waxy. The better you
getatbirdidentification, themorecluesyou'llbeabletointegratetopuzzleoutindividu-
al feathers. But some feathers may be only identifiable by experts in laboratories.
Colorful Characters
Q Someone told me there's no such thing as blue feathers. Is this true?
A
Anyone who has ever observed a bluebird or jay knows darned well there are blue
feathers.Butthereisnosuchthingasblue
pigment
infeathers.Blueinfeathersisa“struc-
tural color,”which means the color we see is duetoaveryspecial arrangement ofkeratin
and air overlying a blackish pigment. When light bounces off this layer, it appears blue.
If you find a blue feather, check it out! When you hold it so the light bounces off it, it
will be bright blue. But when you hold it so it's backlit, either by the sun or any artificial
light, some of the pigment color — a dark brownish gray — will show through.
BudgerigarslivinginthewildsofinteriorAustralia aremostlygreen,whichistheres-
ult of yellow pigments and blue structure. Birds in captivity have been bred for differ-
ent colors. If a bird's feathers lack the yellow pigment but maintain the blue structure,
they'll beblue.Iftheylack thestructure butmaintain thepigment, they'll beyellow.And
if they're lacking both the structure and the pigment, they'll be white.
Iridescence is also caused by feather structure. If you were to grind up a humming-
bird's brilliant throat feathers or the metallic green feathers of a Mallard, you'd end up
with a dark gray powder, the color of the feathers' pigment. But if you ground up some
red feathers from a Scarlet Tanager, the powder would be red because those feathers are
red from pigment.
Q Early last spring, I saw a bird that was shaped just like a robin running on my
front lawn. But it was all white! What was it?
A
It was a robin, but unlike most robins, it was white because it was an albino, lacking
the pigment
melanin.
Birds that are normally or seasonally all white, such as swans,
