Rare sparrows make an appearance at Penn

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Birds likely have a rare genetic condition called albinism, which results from a mutation that prevents adequate production of melanin. (Photo: Doug Wiebe)

To grow, Doug wiebe‘s parents always reported the birds.

“In my family, we used specific names for the species,” explains Wiebe, epidemiologist at the Perelman School of Medicine. “I am far from being an expert on birds, but I have become familiar with birds.”

So when he spotted a little white hopping around the Button sculpture outside Van Pelt Library, he was curious. He and a colleague, also an ornithologist, tried to take a closer look, but couldn’t see much more. “I thought it was so interesting that I went back there with my voucher camera two days later,” he says. “Right there, on the benches in front of the library, there was not one but two. He took some photos and posted them on the iNaturalist app.

Two small birds, one with dark brown feathers and a light brown belly, the other all white.

The birds spotted by Wiebe were mixed with a group of other house sparrows, potentially giving them a better chance of survival. (Photo: Doug Wiebe)

Wiebe had previously used the crowdsourcing forum to participate in the Penn Bird Strikes program, where users can document when they encounter a bird that has collided with a building on campus. There were also regularly published other observations of nature. “People can confirm your observations and then they become usable for research,” he says. “I like the whole citizen science aspect. ”

The iNaturalist community shared Wiebe’s enthusiasm for birds. They turned out to be house sparrows, with their whiteness likely the result of a rare genetic condition called albinism, which stems from a mutation that prevents adequate production of melanin. The other possibility was another genetic condition called leucism in which the pigment does not reach all parts of a bird’s feathers, but usually results in white spots, giving the animal a mottled appearance.

“Totally white birds like these are unusual,” says Kenn Kaufman, bird expert and environmentalist, longtime editor of Audubon magazine. “These individuals also appear to have pinkish eyes, which is true for many albinos, but not all.”

While the appearance is striking, the unique coloring can actually put these people at a disadvantage, says Alison Fetterman, a bird conservation associate at the Willistown Conservation Trust, who co-teaches an ornithology course at Penn. Mate selection, for example, often relies on plumage, so “that coloring may not be as appealing to the opposite sex,” she says.

An all-white bird on a tree with leafy branches behind it.

One of two all-white house sparrows Doug Wiebe of Penn Medicine spotted on campus outside the Van Pelt Library. (Image: Doug Wiebe)

White feathers may not camouflage themselves as well either, she adds, making these individuals more vulnerable to danger than their peers. That said, albino house sparrows – especially those like the two Wiebe, socially intermingling within a larger group of sparrows – might do the trick, Kaufman says. “Living in a highly human-altered environment, they might be able to hold out for quite a while. ”

For Wiebe, the chance encounter provided another window into the hidden nature all around him, on the Penn campus and beyond.

“Since the start of the pandemic, I’ve heard all these stories about the return of wildlife and I love it,” Wiebe says. “As I run from home on campus to exercise, I see birds that I had never seen here before: a northern twinkle, a scarlet tanager; I saw one in Penn Park. He also spotted a peregrine falcon there and later learned that the campus is home to a breeding pair.

He has not seen the rare sparrows since those first two encounters, but he keeps his eyes open for them and all that nature offers him.

Douglas wiebe is professor of epidemiology at the Perelman School of Medicine to University of Pennsylvania. He is also director of Penn Injury Science Center and a principal investigator at Penn’s Leonard Davis Institute for Health Economics.


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