Thursday, August 6, 2009

American Goldfinch

Nature Watch

By Susan Benson,
CNHM Director of Education

Did you know that an American goldfinch pair has almost exactly the same flight call, making it easier to identify them? Or that they adhere to the strictest vegetarian diet, to eat insects only by accident? This week at the bird feeders, the goldfinches filled every feeder space filled on the sunflower seed feeders, striking in their bright yellow colors. It is a joy to see them, or to hear their song, “po-ta-to-chip, po-ta-to-chip” in a steady rhythm.

The American goldfinch is the only finch that is busy molting its feathers two times a year. The first time is in spring, when males display their bright yellow plumage to attract a mate, and then in late summer, as they begin losing their feathers again to become a more drab, olive color throughout fall and winter. The lemon yellow color comes from special carotenoid pigments given special names like zeoxanthin, leutin, and beta-carotene, which come from plant pigments the males consume. The beak is pink for most of the year, but bright orange in both sexes during the spring molt.

American goldfinches breed later than most North American birds, waiting until June or July. It is believed that this timing is better, when milkweed, thistle, and other plants have gone to seed. Goldfinches use these fluffy plant parts to line their nests and the parents also feed their young with the seeds. Spider webs connect the nest to its foundation, and when finished, the nest is no more than three inches tall or wide, and is so tightly woven it can hold water. Goldfinches provide a bird nesting environment that brown-headed cowbirds cannot survive well. Known for laying their eggs in other birds nest, cowbirds will hatch in goldfinch nests, but rarely live longer than three days, not being able to survive on the granivorous, all-seed diet fed to goldfinch young. Once the breeding season is over, goldfinches can be found in large flocks.

The American goldfinch feeds like an acrobat, using its feet to hang from seed-heads, reaching seeds more easily. In the spring a finch feeds on birch or alder catkins, pulling the catkin up with its beak and then holding the catkin still against a branch with its toes. They also feed on maple sap, berries, and tree buds, as well as asters, sunflowers, grasses, thistle, ragweed, dandelion, mullein, and goatsbeard. It will eat at bird feeders provided by humans, particularly in the winter months, preferring thistle or sunflower seed. Flocks of Goldfinches are traveling nomads, moving up to five miles each day from feeder to feeder or other food sources.

To encourage goldfinches into our own back yard, we can plant native composite plants, as well as native milkweed. Then we can have the pleasure of enjoying “our” own group of goldfinches, cleverly called a variety of collective nouns such as, a “007,” “charm,” “rush,” “treasury,” or “vein” of goldfinches. Perhaps that is better than being called a “murder of crows,” a “plump of wildfowl,” a “knot of toads,” or a “sounder of swines.” What will you discover in your own back yard in the coming week?
For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and exhibits, the Curiosity Center and Brain Teasers 2, in Cable at 13470 County Highway M. Also find us on the web at to learn more about exhibits and programs.

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