COLUMN: Some birds lead colorful lives
Many birds here in western Oregon can treat us to a show of color. Some have sharply defined patterns, like a killdeer, chickadee or nuthatch. A few are monotone: crows, bushtits. Others have complex coloration with spots, streaks, or overlapping tones—song sparrow, female mallard, wild turkey, house finch.
That bird in the image above is an adult male house finch. They are common here in town and around farm buildings. Like barn owl and barn swallow, the house finch is comfortable around the habitats people produce.
The bright colors in the bird above are the result of chemical pigments — carotenoids. The finch cannot produce that chemical in its body. It needs to harvest carotenoids from its diet. Some animals that eat the right plants also contain the chemicals. And many plants manufacture carotenoids as part of daily life: seeds from the daisy/sunflower family, lettuce, chrysanthemums, asters, dandelions, goldenrod, coneflowers, artichokes, dahlias, marigolds, zinnias, chamomile, chicory, sage, tarragon, ragweed, sagebrush and yarrow.
House finch plumage is not going to match across a large population. Each adult will have its own level and adaptation of carotenoids in its feathers. That will be influenced by what the individual bird has been eating as it molts into new feathers.
Some of our other local carotenoids users include both lesser and American goldfinch, siskin for their wing patch, oriole, tanager, several yellowish warblers and chat. Also the meadowlark, which is our Oregon state bird. None of these birds has a diet concentrated on insects, or fish, or mammals which are unlikely to carry much, if any, carotenoids.
There are two other pigments birds use in their feathers. These two are produced inside each bird as part of its natural body chemistry. These pigments are melanins and porphyrines. Melanins can produce colors ranging from the darkest black to reddish browns and pale yellows. Porphyrines produce a range of colors, including pink, browns, reds and greens. Some bird species will mix the pigment chemicals to get a unique color.
I have the most interesting bird color for last.
The “blue” we see is not in the feathers. It is in the light frequency a “blue” feather reflects to our mammalian eye and brain. There is no blue pigment in the bird world, so it is our sensitivity to reflected light that tells us “blue.” The way the “blue” bird’s feathers are structured is what lets those feathers absorb all the other light frequencies. The feather above was left in our garden here in Salem by a Steller’s Jay. They are done nesting now so they are starting to molt into new, fresh feathers for the end of summer.
To learn more about bird feather coloration and variation:
https://academy.allaboutbirds.org/how-birds-make-colorful-feathers/
For information about upcoming Salem Audubon programs and activities, see www.salemaudubon.org, or Salem Audubon’s Facebook page.
Harry Fuller is an Oregon birder and natural history author of “Freeway Birding” and the newly-published “Birding Harney County.” He is a member of the Salem Audubon Society. Contact him at [email protected] or atowhee.blog. His “Some Fascinating Things About Birds” column appears regularly in Salem Reporter.
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Harry Fuller is an Oregon birder and natural history author of three books: “Freeway Birding,” "Great Gray Owls of California, Oregon and Washington," and "San Francisco's Natural History--Sand Dunes to Streetcars." He leads birding trips for the Malheur Field Station. He is a member of the Salem Audubon Society, and leads bird trips locally. Harry has just published a new book, BIrding Harney County.
