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Bird Coloration: Pigments and Structural Colors
Jul 22 2011 5:00:00 pm EST
Topics:The remarkable diversity in color and iridescence of birds is achieved by pigments and structural colors.
Pigments are colored substances that reflect certain wavelengths of light, while absorbing others. It is the reflected light that is identified as the pigment’s color. Pigments are located on the skin or feathers of the bird and are independent of the structure of the feather. Bird pigments come in three different groups: melanins, carotenoids, and porphyrines.
Melanins are the primary determinate in human skin color. They also serve to color the skin and feathers of birds, as well as providing strength and durability to feathers. Melanins produce blacks, reddish browns, and pale yellows.
Interestingly, a feather without any pigmentation is the weakest of all. White birds will often have melanin fortified black feathers on their wings where they are subject to the greatest stress.
Carotenoids are naturally occurring organic pigments in the chloroplasts and chromoplas
On Evolution Of Flight, D'Arcy Wentworth Thompson
Jun 5 2011 9:26:02 am EST
Topics:Nature has developed many dynamic and efficient solutions to break its ties to the ground. The soaring Bald Eagle circles upwards in thermal updrafts, catching the wind in its long broad wings, gliding from updraft to updraft during migration. The Wandering Albatross repeatedly dives into the valleys of ocean waves, wheeling back up into the air, utilizing dynamic soaring to travel many thousands of miles using very little energy from flapping. Canadian Geese maintain continuous flapping flight in formation to reduce drag. The voracious hummingbird beats its wings anywhere from 8-100 times a second, depending on size, and generates thrust in both the upstroke and downstroke to maintain hovering flight. Not to mention the wonders of insect flight…
However, nature, as man, began with rudimentary evolutionary experiments. As we have refined human technology over hundreds of years, so has nature over hundreds of millions of years.
D’Arcy Wentworth Thompson summari
A little after three months since my bird feeder setup, I’ve made many changes. Namely, I spent a lot of effort deterring squirrels.
Naively, I set up my bird feeder within three feet of trees. This was plenty enough distance for squirrels to lunge on the feeder pole. No matter how many squirrel baffles or how much grease I put on, they’d gather like a pack of zombies on human flesh. I’d chase them away, but they’d be back minutes later.
It got to the point where five squirrels were hovering around the feeder most of the day. The birds couldn’t get in edgewise, so I had to move the whole setup into my back yard.
I made sure to trim nearby branches, and place the pole over five feet from any possible jumping points. They still exhibit obscure problem solving methods to circumvent baffles. I end up making small modifications, and they aren’t nearly the problem they once were.
Although the view to the back yard from the kitchen is not as ideal as the view from the
I wrote an article outlining how long it took for birds to visit the feeder, as well as what species of birds I’ve observed.
So far, I’ve observed six species of birds, as well as some persistent squirrels.
Set up a bird feeder and fountain to attract birds. Have had it for over a month now. In the following article, I review the cost of setup and materials for my feeding station.
So far, I’ve counted six species of birds that have visited my station, averaging a new bird type every week. I used Cornell’s web based bird guide, to make positive identifications.
