 On this page:
Color
variants
Deformed bills
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| Project FeederWatch began collecting data about plumage variations in 2000. Between 2000 and 2007, 1,605 Unusual Bird Forms have been submitted, reporting a variety of plumage oddities in birds. |
Larry Newman, Lab volunteer, charted the unusual bird reports filed from 2000-2006. He created the pie chart at right, which shows that albinism is by far the most common oddity observed by project participants. Of 1,605 Unusual Bird Forms submitted during that time period, 61% contained reports of albinism. Bill deformities were the second most commonly reported abnormality at 15%. The unusual bird traits are described below (except for bald-headed birds, which are described elsewhere). |
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| Notes about the chart: Some birds were reported with more than one plumage variation, which makes the percentages add up to more than 100%. Reports of House Finches with xanthochromism were not included in the chart because the color of these finches is related to diet, and yellow or orange coloration is considered normal in House Finches (learn more about color variation in House Finches). |
 Color
variants
| Sometimes strange-looking birds show up at feeders. For example, you might see a bird that looks like a white cardinal, such as in the photo at right. Or you might see a bird that looks like a House Finch except that it is yellow instead of red. Most likely the birds are what they appear to be, only with some sort of color variation. |
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Partially Albino Northern Cardinal,
photo by Greg and Annette Stewart, Thamesford, Ontario |
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If you see a strange-looking bird use size, shape, and behavior to help identify a bird. Comparing the strange bird with other birds nearby can be helpful.
Partially Albino Mourning Dove,
photo by Herman Paulk, San Bernardino, California
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Types of genetically based color variations: |
Albinism is the absence of pigment. Albino birds, such as the Rock Pigeon shown at right, have absolutely no pigment in their feathers, bills, or legs, and their eyes appear red.
Albino Rock Pigeon, photo by Herman Paulk, San Barnardino, California |
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Melanism, or extra dark plumage, is another genetic color variation. Melanism refers to the abnormal deposition of the pigment melanin. As can be seen in the pie chart at the top of the page, melanism is seen far less frequently than albinism (3% versus 41% of unusual bird reports).
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| Melanistic White-winged Dove, photo by John Pavesi, Cedar Park, Texas |
Leucism, often confused with albinism, means that a bird has feathers that appear lighter than normal, as if the bird had been dipped in semi-opaque white paint.
Xanthochroism: yellowish or orange plumage, usually instead of red. While orange or yellow House Finches are often thought to have xanthochroism, their color variation is actually diet based. House Finches are typically yellow or orange in the west because of their diet. Learn more about color variation in House Finches.
Erythrism: abnormally reddish plumage |
Deformed bills
Sometimes FeederWatchers observe birds with odd looking bills. A 1999 article in BirdScope first reported Project FeederWatch participants observing bill deformities.
Scientists are studying this phenomenon in Alaska, where the problem seems to be most prevalent. Colleen Handel, a biologist with the United States Geological Survey's Alaska Biological Science Center, has compiled reports of deformities in 28 species in Alaska. |
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| Hairy Woodpecker, photo by Deb Apperson, Anchorage, Alaska |
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By far the most bill deformities are reported in
Black-capped Chickadees. A cause for the deformities has yet to be determined. Learn more about Colleen's research.
From 2000 through 2006 Project FeederWatch collected 215 reports of bill deformities, representing 38 species from 38 states and provinces. As with Colleen's data, Black-capped Chickadees were reported most frequently, making up 30% of the reports.
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Photo by Bonnie L. Long,
Anchorage, Alaska |
House Finches were reported the second most frequently with 21% of reports. The majority of bill deformity reports came from Alaska--31% of all reports received, while 12% of reports came from California, the state with the second highest total. FeederWatch is providing summaries of reported bill deformities to Colleen to assist in her research.
FeederWatchers may contribute information about bill deformities as well as other oddities by submitting an Unusual Bird Form online or by submitting a written report. |
| Other oddities |
| Once in awhile we see something incredibly unusual, like this very strange looking Blue Jay. See more photos. |
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