On a cool, sunny April morning, three robins hopped sprightly in the dewy grass, not far from the sidelines of a noisy soccer field where two youth teams were competing.
The birds all hopped like robins. They chirped like robins. They all had rusty breasts and their mannerisms were all robin-esque but one of them stood out against the bright green background.
Where two of the birds had the familiar slate brown feathers on head, back and tail, the third stood out like a phantom in silver-white shroud.
This robin was not albino -- its eye was dark, not pink, and its legs were normally colored. What could it be?
Abnormal paleness in birds' plumage is not uncommon, said Chuck Hagner, editor of "Birder's World" magazine. The term for this bird's plumage is leucism.
"We get reports of plumage abnormalities all the time, and they come from all over the place," Hagner said.
People don't know what to call these abnormally-colored birds, and the terms "partial albinism" or "imperfect albinism" have cropped up. But that term is inaccurate, according to Hagner.
"When you get to these birds that aren't entirely white and don't have a pink eye, you're into this in-between area, and people's vocabulary peters out," Hagner said.
Leucistic birds retain their characteristic pattern but appear slightly or extremely washed out, Hagner said, referring to information he found in "The Birdwatcher's Companion" by Christopher Leahy. These birds are abnormally
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pale in plumage resulting from a dilution of normal pigment.
Leucistic animals possess the pigment melanin -- the pigment that is absent in albinos -- so they retain dark eyes and some other normal body colors, according to Leahy, and may in some cases be related to an abnormal diet.
The Cornell Lab or Ornithology, Ithaca, N.Y., explains the difference in birds even further by quoting C.J.O. Harrison (1963): ... "leucistic individuals have melanin in the body, giving dark eyes and colored soft parts, but the melanin does not enter the feather structure ... ; albinistic individuals lack melanin in the body as well as the plumage."
This leucistic robin was noticed last month by Mark and Clara Schroeder, Shippensburg, on one of their daily walks in Southampton Township (Cumberland County) Municipal Park. Their grown daughter, Amanda, walking that day with her parents, saw it first and asked them, "What's that bird?"
The Schroeders recognized the familiar robin habits and saw that it was working the turf with other robins. Mark Schroeder, using the strongest telephoto lens he had, took several photographs of the bird in the grass and in branches of nearby trees.
Both retired educators -- he from Shippensburg University, she from Chambersburg Area School District -- the couple could make regular note of the bird's habits. Each day they saw it in the same general area of the park. It was seen carrying nesting material as it flew among leafing twigs and would rest particularly in the crook of one branch. There was no hiding its flashing white plumage as it darted in and out of the woods.
"There is a cost," said Hagner. "Those kinds of birds will stand out visually to predators, and they have a harder life for that reason. "A bird that relies on its plumage to hide or blend in (will) be seen by hawks and squirrels that like to raid nests."
That question answered, another remained: Was it a male or female?
Females are told from males by "that dark black cap that males wear," Hagner said. Because male robins occasionally help the females build nests, it could be either.
The Schroeders have not seen the robin since late April. They can only hope it's a female, sitting on her nest tucked away in the woods.
Note: A leucistic robin has been reported in the Fayetteville area as well.
