A Cinereous Vulture Success Story
She’s gothically stylish, draped in dark brown and black feathers that adorn her massive wing span and sprout from a neck ruff resembling a monk’s cowl. At 5 months old, she weighs 16 pounds—nearly as much as her dad. She lives near her parents and is already looking for her own place to roost. She eats rats.
Vultures get a bad rap in popular culture. Cartoons cast them as grotesque outcasts. We equate the name with greedy opportunists who take advantage of others’ misfortunes.
That’s a lot of baggage to overcome. But seeing Sophia perched on a branch near her European white stork and Himalayan monal neighbors, you think “regal” not “repulsive.” This is one awesome avian ambassador who provides fresh perspective on her scavenger species.
Cinereous vultures are one of the largest birds of prey in the world with wingspans up to 10 feet. In the wild, they soar at high altitudes over remote dry plains, grasslands and mountainous forests seeking carrion—from large mammals to fish to reptiles—with superior vision.
“They’re nature’s cleaners,” says Sunny Nelson, the zoo’s Hope B. McCormick Curator of Birds. “They fill a really important ecological niche. We’d have real issues if they weren’t there.”
Yet this is a species threatened across its Eurasian range by habitat loss and a contaminated diet, says Nelson.
“They’ve had to go farther and farther to look for food,” she says, “and often the items they eat are contaminated with pesticides and other harmful manmade products.” In Spain, the establishment of “clean carcass areas” has helped the population in that country recover from the brink—providing a helpful lesson for other conservation efforts.
Vultures living in zoos faced a different problem.
"Some vulture pairs have been known to break their eggs during the incubation process," says Nelson. Because of this, the Cinereous Vulture Species Survival Plan, a shared conservation effort among zoos, recommended that animal care managers pull eggs laid by vultures and replace them with artificial eggs. The real deal—the future Sophia this past spring—was placed in a Bird House incubator. Meanwhile, Bruno and Lurch—none the wiser—took turns sitting on the fake. The plan was to switch the eggs again right before the chick hatched.
Cinerereous vultures have an incubation period that can last as long as two months. Bird keepers kept an eye on the calendar, but then...
“On day 52, just as we were getting ready to put the egg back, they abandoned the nest,” says Nelson. “So we had to hatch the egg out here on June 7 and artificially rear the chick.”
In the process, zoo veterinarians discovered another potential problem during an examination: Sophia had a cardiac murmur. The family reunion would have to wait as the hand-rearing continued to make sure the chick grew strong enough to be on her own. This presented yet another challenge.
“There’s this critical period when they’ll imprint on the caregiver,” says Nelson. “That’s usually mom and dad, but it could be a human caregiver, and we don’t want that to happen.”
Implementing an approach called “blind rearing,” keepers fed the tiny, fluffy, white chick from tweezers gripped by an elaborate hand puppet resembling an adult vulture’s head and neck.
“I came back to the office and one of our keepers, James McKinney, had made the puppet from papier-mâché,” says Nelson. “I said, ‘That’s not a normal puppet—that’s fantastic!’”
Keepers also fed Sophia through a hole in a sheet they suspended in the Bird House’s brooder room. The ruse was bolstered by a mirrored surface in Sophia’s intensive care unit that let her see her own reflection.
After 20 days Sophia was eating on her own and keepers were able to take her on “howdy” visits with the parents from outside their enclosure. The introduction process proceeded as she grew stronger, able to reliably stand on her own and pick up and pull things apart. Cinereous vultures grow fast, gaining 10–15 percent of their body weight per day. Adult females, who are larger than their monogamous mates, can weigh as much as 30 pounds.
Chicks fledge at about 3–4 months, but independence from the parents is rather relative when the family lives close together.
“We shifted from supervised visits to letting her stay out there longer and longer with keepers present,” says Nelson. “Then we let her stay out all day by herself with periodic watches until finally we could leave her there to spend the night. She’s part of the group now.”
Sophia looks like an adult, but you can identify her by her darker, blackish plumage—likely to lighten next year after her first molt.
“We can say she still has baby eyes, too,” says Nelson, “but I’m not sure the general public could determine that.”
Craig Keller • Published October 31, 2013
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