An albino mockingbird would have red eyes, but this leucistic white mockingbird, which has been hanging around Walton Heights in Little Rock since mid-October, has pigmented eyes.

When it first showed up in her yard in Little Rock, Kathy Aday's neighbors didn't know what to make of the ghostly white bird.

Photo by Rick McFarland

Kathy Aday was out of town when neighbors noticed a white mockingbird in her backyard on Walton Heights.

Photo by JERRY BUTLER / Special to the Democrat-Gazette

Northern mockingbirds typically have gray feathers, and males and females closely resemble one another.

Photo by Rick McFarland

This white mockingbird hangs out in a yard well-outfitted with feeders in Walton Heights, a Little Rock neighborhood atop a ridge near the Arkansas River.

Was it an exotic winged species from another country or an escapee from the zoo?

It was shaped like a very common bird in Arkansas, in fact, the most common backyard variety, a Northern mockingbird. The mockingbird is so common in the region it is the state bird for Arkansas and three adjacent states.

Besides the right silhouette, the bird that was flitting about in Aday's area, Rivercrest Drive in Walton Heights, had the edgy behavior and the chirps and slender body, but its color was all wrong. Mockingbirds are typically gray with light underparts.

This one had pearly white feathers with dark legs, bill and eyes.

Aday was out of town when a neighbor sent her the photograph. The photo was shared on social media by her neighborhood association, and eventually found its way to Dan Scheiman, bird conservation director for Audubon Arkansas. Scheiman identified it as a Northern mockingbird.

"We have really enjoyed seeing the bird," Aday says. "It plays, chases other birds around, and will run them off if they get too close."

Aday's house has a bird-friendly backyard that overlooks the Arkansas River. She maintains three birdbaths, a birdhouse and three bird feeders, which she takes indoors each evening lest they be raided by raccoons.

"The white mockingbird remains close by most of the time and can be easily found even in the middle of the day," she says. "Since it first arrived it has never been away for an extended time."

I visited the Aday home in hope of seeing the rarity for myself. I hadn't been in the yard 10 seconds when the bird flashed before me and landed atop a purple martin birdhouse.

In an hour and a half of observing the white bird, I determined that it most likely was a female. Normally, male and female mockingbirds are colored the same, and they both sing, but the males tend to sing more. This white bird seemed to stay in the company of another mockingbird, a typically colored gray one that was much more vocal.

I heard the white mocker give only soft chirps a time or two, but the other one belted out imitations of blackbirds, chickadees, meadowlarks and warblers, repeating each song three times.

Both birds tolerate humans approaching them (more tolerant, it seemed to me, than other mockingbirds I've observed). Mockingbirds are strongly territorial in general, and these chase away sparrows, titmice and woodpeckers. But the white mocker remained in the backyards of the Adays and their two adjacent neighbors while I was there, even though a neighbor's lawn guy was running a leaf blower.

I would briefly lose sight of it only when it entered a thick hedge, oak or dogwood tree. Its

lack of camouflage made it easy to find again even without binoculars.

Later I called Scheiman and described what I'd seen. He thought my assumptions about the white bird being a female and the other mocker being its mate sounded "likely" to him, "but we can't say for sure."

Isn't being white and easy to spot from a distance a biological disadvantage to a bird in the contest for a mate?

"Among some birds with vivid plumage it might be," he said. "But among mockingbirds, the female chooses the mate, based not on color but on the strength of the repertoire of the male mockingbird's songs."

In the Sadie Hawkins world of mockingbirds it's ladies' choice, and the lady chooses the gent that can sing the most songs -- not the one that can fly the highest, strut the best or display its feathers like a peacock. Female color is apparently of little consequence.

If the white bird survives until next spring's nesting season, and if it nests in the yards it has been frequenting, Aday and her neighbors will be able to observe whether the birds are mates and which is female.

SERIOUS PLAY

The active "play" that Aday observed may have been more than that.

Any wild creature that has a noticeably unusual genetic trait is subject to harassment by its peers. Birds are not always tolerant of those whose feathers are a different shade. This white mockingbird does not have an enviable future. In addition to being harassed by other birds, its lack of camouflage will make it more susceptible to attack by predators.

Scheiman says that each year he gets two or three requests to identify birds with unusual white feathers, but he's reluctant to estimate the frequency that such birds occur in nature. "It is very unusual," he says, "or else it wouldn't be called to my attention."

He has been asked to identify hawks, crows and sparrows with white feathers. This was his first white mockingbird.

NOT AN ALBINO

Color aberrations in birds have been observed by humans for centuries and on occasion such birds have been assigned mystical significance. Thanks to biochemistry, we understand the causes. Pink flamingos and the scarlet ibis absorb their color from shrimp and other crustaceans they eat. If they are fed other kinds of food while in captivity, they lose their vivid color, becoming pale and drab.

Dietary change is not a plausible explanation for whiteness in wild songbirds, however, because they stay the same color no matter what they eat. A genetic malfunction is the most likely cause.

"Albinism is a total lack of melanin pigmentation in feathers, eyes and skin as a result of an inherited genetic anomaly," according to Hein van Grouw, bird specialist with the Natural History Museum in London. In a research article titled "Not Every White Bird Is an Albino," he describes birds that, like the mockingbird in Walton Heights, have pigmented eyes and yet are commonly described as "partially albino." That description is a contradiction in terms, he writes.

"Partial albinism," he contends, "is simply impossible, just like being 'partially pregnant.'"

Grouw and other scientists prefer the term "leucism" and "leucistic" to refer to abnormally white birds.

In leucistic birds and animals, the melanin pigmentation is present, but because of a disturbance in the pigment transfer due to a genetic disorder, feathers or fur remains white.

Leucism has been noted in hundreds of bird species, from penguins to parrots. (Some ornithologists contend that the woodpecker seen in the video image taken in the Big Woods of east Arkansas 12 years ago was a leucistic pileated woodpecker and not the whiter ivory-billed woodpecker.) A leucistic bird might have entirely white feathers -- like the bird at Walton Heights -- or it might have normal coloration in most places but an uncharacteristic white head or primary wing feathers.

The white mockingbird at the Aday residence is a rarity that even the most diligent bird-watcher may never witness in a lifetime of observing those winged creatures that make a birder's heart sing.

Jerry Butler writes about Arkansas birds and the people who enjoy them. Share your comments and stories at jerrysharon.butler@gmail.com.

ActiveStyle on 11/09/2015