After five years of efforts that included bird-swapping, an egg-laying tragedy, and long hours of observation and nest engineering, the Baltimore Zoo has another little scavenger to feed.
The zoo is crowing about the first captive breeding and hatching in North America of an African lappet-faced vulture.
Zoo director Brian A. Rutledge noted that the large, powerful bird is not particularly rare in its natural habitat. The biggest of the African vultures, it is commonly seen following herds of wildebeest across Tanzania and Kenya and ranging throughout the continent.
But in all of North America, there are perhaps 50 -- every one of them taken from the wild for exhibition in zoological parks. And for Mr. Rutledge, the hatching two weeks ago was a landmark event in helping zoos turn away from being "consumers of wildlife."
"We hope to create a situation where [animals] that are captive willreproduce themselves, and we will not have to catch them and be a consumer of wildlife," Mr. Rutledge said.
Zoos do breed many of the animals they exhibit, but reproduction is difficult to manage with some species. Others -- like the lion-tailedmacaque under study at the Baltimore Zoo -- are so threatened in the wild that captive breeding may be their only hope for survival.
Humans have been the biggest threat to wildlife. Development has decimated the Amazon rain forests and shrunk the mountain forest of southern India that is home to the rare macaque, while hunting has vastly diminished the populations of such animals as elephants, rhinoceroses and gorillas.
The vulture breeding project was managed by the Baltimore Zoo's longtime curator of birds, Fred B. Beall, whose staff has kept the birds under close observation in an old camel barn converted into cold-weather quarters.
Four of the birds were obtained by the zoo in 1978, and the first breeding problem was sorting out the sexes. Keepers found out in 1986 that one of the birds thought to be a male was really a female. The problem was solved by trading a female to the Detroit zoo, which had three males and one female.
The birds were removed from public display five years ago, limiting human distractions and variables as keepers began studying vulture behavior -- and making life cozy enough for the monogamous creatures to bond and mate.
The keepers found nest engineering to be a key element -- determining the size, elevation and amount of overhead space needed to accommodate the physical act. "Observations indicated the pairs only copulated on the nest. With the nest too high, it wouldn't allow the male to mount the female," Mr. Beall said.
"Unfortunately, we had a sad mishap this time last year with the second pair," he said, recalling that one of the females died as a result of being "eggbound."
The helpers worked for hours to remove the stuck egg, but a week later, just as the female appeared to be "on the road to recovery, . . . sheall of the sudden crashed, and her health status went down very quickly," the curator said.
The death has left one of the male birds without a mate, and zoo officials are searching for a replacement. But most of the birds in North America seem to be in pairs and unavailable, Mr. Beall said.
The hatching of the other female's egg this month was believed to be only the third to occur in captivity worldwide, Mr. Beall said, following by several years breeding successes with the vulture species in the Netherlands and Israel.
The lappet-faced vulture -- named for the purplish-gray or pinkish rolled folds of skin on the head and face -- is, like other types of vulture, buzzard or condor, a carrion-eater that patrols in the sky, searching the earth for dead bodies.
"They really serve an important purpose in the wild," Mr. Rutledge said. "They're maximizing the value of protein. It doesn't rot and go through the earth. It goes through the vulture system. They clean upthe land."
The Baltimore Zoo has two other species of African vulture: the smaller white-headed vulture, which is very common and on public display in the sitatunga exhibit across from the Nile hippopotamus, and the white-headed vulture, a large bird that is well represented in the wild but extremely rare in captivity.
"In the U.S., there are only five white-headed vultures in captivity right now, three of those in Baltimore and the fourth expected in the next month," Mr. Beall said.
Like the lappet-faced vulture, which has a lifespan of 50 years, the white-headed species is off exhibit and housed in the camel barn. He estimated that his staff will have three to five years before the vultures reach sexual maturity for breeding.
The keepers are quietly watching the development of the white, fuzzy lappet-faced chick. If the tiny vulture survives, zoo officials say, it is destined for public display.
That, said Mr. Rutledge, is what captive breeding is all about.