Tuesday, March 22, 2016
As I do every morning I was looking out my bedroom window. Today there are wind advisories but there was only a gentle breeze every now and then. That is when I spotted a curious thing.
It landed in the neighbor's cedar tree. I paid little attention thinking it was probably a blackbird or crow. Goodness knows there are a lot of them here. But no.
I saw the distinctive crest. I saw the longer beak. It flipped its tail up. Except for the black color it looked and acted like a blue jay.
After I saw that black deer a while back I wondered exactly what it was that I was seeing. When I finally got up and got dressed I went to my computer to see what information I could find about black blue jays.
Blue jays are corvids. They are members of the family that contains crows, ravens, nutcrackers, and magpies as well as several other birds.
Corvids are considered to be among the most intelligent animals. The total brain to body mass ratio of corvids is equal to the brain to body mass ratio of great apes and slightly lower than that of humans. They make and use tools. They recognize themselves in a mirror. They mimic sounds including human speech.
Blue jays are easy targets for the birds of prey because the jays fly so slowly. The jays are beneficial to other birds however. Because they have such a piercing scream in times of danger they give a warning to other birds that need to find safety.
Blue jays eat seeds and grain. Their strong black bills are iseal for cracking nuts. They will eat food scraps left by humans. it is rare but they will sometimes even eat eggs from unguarded nests. Theyhave at times caught small insects as they are flying.
This is the time of year that blue jays mate. From the middle of March to as late as July is their nesting period. They mate for life but it is the female who sets on the nest. The male provides her with food until the chicks hatch.
The nest will contain from 3 to 6 eggs in a cup shaped nest. They use whatever materials are available. They prefer evergreen trees but nests have been found in odd places like mailboxes. They will also appropriate nests of other birds.
In about 2and 1/2 weeks the eggs hatch. That parents feed them for another 3 weeks. After that they fledglings go their own ways.
So back to the bird I saw this morning. A black blue jay?
A blue jay's feathers are black!
There are color producing units in the barbs of the black feathers. There is a dark layer of cells containing melanin. Those cells are covered by box cells which are covered by a colorless transparent horny outer layer. There are air filled cavities of irregular shape and they scatter the light.
When sunlight shines on the feather it passes through the transparent outer layer of the barb and hits the air filled cavities scattering the blue light and absorbing red wavelengths. The blue light is absorbed by the melanin and that is what we see.
The reason I saw the blue jay as black is because of the distance and a lack of sunshine this morning. I was too far away to see that gorgeous blue color.