Donna
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« on: 07-Sep-10, 07:19:14 AM » |
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Sadie McGee sat on her new double-level deck looking at hummingbirds flitter back and forth from the sugar feeder. The birds had metallic green backs and ruby red chests. Unexpectedly, however, McGee also saw a streak of white.
“I thought it was a figment of my imagination; the belly might have been white,” McGee said.
The bird kept showing up every day. McGee took photos and soon realized it was a white hummingbird, a rarity only seen by a handful of people each year.
The white hummingbird isn’t albino, a condition where no pigmentation can be formed. Instead, it is what is commonly known as leucistic, a trait found in animals and humans as well. It’s partial albinism, but the eyes and other features maintain color.
“Hummers with this condition are extremely rare,” Robert Daly, biology professor at the University of North Alabama, wrote in an e-mail. “I hear about one in this area every couple of years, but I have never been able to catch and band one due to their migration farther south.”
Daly is a bander affiliated with the Hummer/Bird Study Group, a nonprofit group geared toward preservation of hummingbirds. Banding involves catching and tagging or marking the bird to monitor its activities.
“Like with other leucistic/albino organisms in the wild, long-term survival is very unlikely,” Daly wrote. “Predators of all types focus in on the ‘white’ color. I would expect this bird to head south at any time.”
Data on leucistic hummingbirds are lacking, but “after 15 years of fielding queries and looking at photos, I would say about 10-15 are reported (to someone, even if not to us) every year,” Ross Hawkins, executive director of the Hummingbird Society, wrote in an e-mail. “Few are pure albino; most are leucistic, and a few are partial albinos. So to see one, of any type, is pretty rare!”
George Barrowclough, associate curator of ornithology at the American Museum of Natural History, has seen thousands of hummingbirds, but the only white one he has encountered is the sole one in the museum’s collection in New York City.
“It’s very unusual in my experience,” said Barrowclough, with more than 30 years as a researcher under his belt.
Barrowclough said the more scientific term for the condition of the white hummingbird is schizochroism, in which one or more pigments’ production pathways are turned off.
“There’s really a cost of not having pigment in your feathers,” Barrowclough said, particularly from the standpoint of the bird losing its camouflage, which is important to thwart prey.
“From a natural history standpoint, it’s costly to lose your pigment,” he said.
McGee moved to Alabama in 2007 after being a Navy nuclear mechanic for the past eight years. She put out her first hummingbird feeder, one taken over by a dominant male.
This summer, she put out a second source of sugar water that attracted a growing number of hummingbirds.
Cathy Markovitz, a neighbor, visited McGee on a recent Thursday.
Both watched as the white hummingbird flitted from branch to feeder before disappearing into a wooded area behind McGee’s home.
The evening before, McGee said, she filled one feeder with her recipe of two cups water and half a cup of sugar. The next afternoon, half the solution was gone.
“They’re going to be fat hummingbirds if they go through that much,” Markovitz said.
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