Breeding Program for Pondicherry Vultures

Abstract

Of the eight species of vulture found on the Indian Subcontinent, the Pondicherry (Indian Black) Vulture, Sarcogyps calvus, appears to be among the most vulnerable (Houston 1986). A solitary carrion-feeder which was never encountered in large numbers, this species' population has been further reduced in recent decades, probably in relation to widespread destruction of preferred habitat for this forest-loving vulture. While still considered common in northern portions of the Malay Peninsula and South Vietnam, reports indicate that populations throughout the majority of the range have declined in recent years. The decline in some areas, such as the nation of Bangladesh, appears to have been dramatic (Sarker 198 3). Jhe Pondicherry Vulture, as a species, is rarely represented in zoological collections in the United States. The most recent census indicates a U.S. captive population of eight individuals, five of which are offspring of the breeding pair currently exhibited at the Jacksonville Zoo. This pair has successfully produced a single offspring each year in 1983, 1984, 1986, 1987 and again in 1988. While several specimens have been located at major zoological collections in Europe and Africa, no record of captive reproduction has been indicated other than with the pair at the Jacksonville Zoo. In addition to providing offspring available for future breeding programs at Jacksonville Zoo as well as other facilities, this program has allowed an opportunity for research concerning the captive reproductive behavior of this species. This information was acquired through an ethogram which was conducted on the adult pair during the 1987 breeding cycle at Jacksonville Zoo. The data obtained from this study were combined with reference material on distributions and populations of this species throughout the natural range and presented at the 1987 AAZPA National Conference in Portland, Oregon. This paper, titled "Status of the Indian King (Pondicherry) Vulture in the Wild and in Captivity,'' is included in the published proceedings for this conference (Penny, 1987).

Representing the only species within the genus Sarcogyps, the Pondicherry Vulture is quite distinctive in appearance, possessing a large wattle of skin behind and below each ear, with a pinkish red head and a neck bare of feathers. The general appearance of the head and neck provides at least a superficial resemblance to the Lappet-faced Vulture, Torgos tracbeliotus, of Africa. Eye color within individual Pondicherry Vultures is variable, with some birds having dark brown eyes and others possessing pale yellow eyes. No evidence exists at this point to suggest that eye color is related to sexual dimorphism. With the adult pair at Jacksonville Zoo, the male has yellow eyes and the females are dark brown, as verified during observations of copulations during the spring of 1987. Plumage of adult birds is basically black tapering to dark brown on the lower back, wings, and tail. Two white patches of down on the base of the neck and lower flanks are particularly evident in flight. The bill is dark brown and relatively large.

 The lower legs of the species are red, similar in color to the bare skin of the head and neck. Juveniles of the species are similar to the adults, but brown rather than black in plumage. Weight obtained on a 14-month-old bird at Jacksonville Zoo was 3.7 kg (8.1 lbs) with a head to tail length of 79.4 cm (31-1/4 inches). Wingspan measured 213 .4 cm (84 inches). These measurements are estimated to be slightly less than those of the adults on exhibit.

While the Pondicherry Vulture is reported to be rather solitary in its habits (Grossman and Hamlet, 1964), it is noted to be wide-ranging as a species, occurring in southeast Asia from India eastward to Vietnam and the Malay Peninsula (Meyer de Schauensee, 1984). Several gaps appear to have developed in the original distribution within the last two decades, however, as the species is reported to have become extinct in Sri Lanka and Bangladesh (Sarker, 1983). According to Houston (1985), it is less common in Thailand than previously reported. In accordance with its solitary nature, most sightings of the species are of a single bird or a pair, even at carcass feed sites where dozens of vultures of other species are gathered (Baker, 1928; Grubb, 1983 ). Breeding activity throughout most of the Pondicherry Vulture's range begins as early as December, reaching a peak in February and March. Nesting is reported to almost always occur in trees or high brush and seldom, if ever, on cliff sites (Grossman and Hamlet, 1964). A substantial nest platform of sticks and branches is constructed by both male and female, a behavior which was verified in the captive pair during the 1987 behavioral study.

Concerning the captive reproductive history of Pondicherry Vultures at the Jacksonville Zoo, the pair currently breeding was acquired as adults from Southwick Wild Animals in 1965. For the next eight years, they were housed in a 3.0 x 4.0 x 3.0 meter enclosure with concrete floor. In 1973, they were introduced to a new 30 x 35 x 10 meter flight cage, sharing this enclosure with a variety of birds of prey. Current cagemates include a trio of Marabou Storks (Leptoptitos crumeniferous) and a single Grey Buzzard Eagle (Geranoaetus melanoleucus). Several species, including an Egyptian Vulture, a Bataleur Eagle pair and a Great Black Hawk, have been removed from the enclosure over the years, due to excessive aggression by the Pondicherry Vultures. All species within this enclosure are fed during the late afternoon, with the diet of 15 to 20 fish (spot spp fortified with vitamin B-1 tablets), distributed across the top surface of a series of tree stumps, approximately three to four feet in height, which are scattered at intervals across one side of the exhibit. This daily ration is supplemented three times weekly with four to six pounds of Nebraska brand Bird of Prey diet. Amounts of these diet items are adjusted periodically throughout the year in accordance with fluctuations of appetite observed within the exhibit specimens. While the Marabou Storks generally are the first to arrive at the food logs each evening and prefer the fish, the Pondicherry Vultures and the Buzzard Eagle will often join the feeding scene before the larger Marabous have departed and appear to eat the fish as well as the Bird of Prey diet readily. Large, domestically raised rats, which are occasionally added to the diet, are usually eaten quickly by the Marabou Storks, with the birds of prey disposing of any remaining portions. No breeding activity from the vultures was observed until 1982, when a nest was constructed approximately 7 .0 meters above ground in an oak tree and an egg unsuccessfully incubated by the parents. The birds renested during the following winter and began sitting tightly on the nest on February 4, 1983. Due to dense foliage surrounding the nest site, actual observation of the nesting activity was difficult and our staff was unable to verify length of incubation and fledging period. The juvenile was first observed sitting on the edge of the nest on July 14, 1983 and had fledged by August 1, 1983. Excessive interest by the trio of Marabou Storks required removal of the fledgling vulture that same day where it quickly adjusted to self-sufficiency on a diet of Bird of Prey.