The range of bearded vultures extends across southern Europe and Asia, from as far east as the Pyrenees mountains of Spain to as far west as India and Tibet, south-central China, and southern Siberia. They can also be found across the Ethiopian highlands, as well as in northeast Uganda, west Kenya, Lesotho and southeastern South Africa. Isolated populations inhabit northern Morocco and possibly Algeria. (Ferguson-Lees and Christie, 2001)
There are thirteen different subspecies of bearded vultures, though most lack sufficient grounds to be wholly considered. Gypaetus barbatus barbatus is restricted to northwest Africa, while Gypaetus barbatus meridionalis can be found throughout eastern Africa and the nation of South Africa. Gypaetus barbatus aureus can be found throughout Europe and Asia, while Gypaetus barbatus altaicus are found only in the Himalayas and mountains of central Asia. (Ferguson-Lees and Christie, 2001)
Bearded vultures can be found at high elevations in mountainous regions. They reside between 300 and 4,500 meters above sea level, though most frequently above 2,000 meters. They often inhabit desolate areas containing cliffs, precipices, or gorges overlooking pastures and meadows where prey animals and their predators reside. Inhabiting such an area gives scavenging bearded vultures potential access to the remains of hunted-down prey. (Birdlife International 2009, 2010; Ferguson-Lees and Christie, 2001)
Bearded vultures are extremely large vultures that range in weight from 4.5 to 7.0 kg, have a total length between 94 and 125 cm and a much longer wingspan of 231 to 283 cm. Sexes are very similar in appearance, though females are, on average, slightly larger. Adults are a dark gray-black or gray-blue, with a slightly darker tail and lighter shaft-streaks. Each side of the face is separated by a thick black band around the eyes, with long, broad black bristles at the base of the bill that resemble a beard. The forehead is a cream color, while the rest of the head is a maize color, often becoming more of a rusty orange color on the neck and abdomen. This rufous coloration is caused by bathing in iron-rich water, and variation in bathing time among individuals results in different shades of color in these areas. Unlike most vultures, bearded vultures lack an entirely bald head and feature an almost shaggy, fully feathered neck and legs. Increased featheration is likely due to differences in diet; bearded vultures subsist mainly on bones while most vultures primarily consume carrion.
Juvenile bearded vultures have a much different physical appearance than adults. These birds possess a dark gray-brown coloration, with a slightly lighter gray-brown abdomen and a dark brown to black colored head and neck. Due to this dark coloration, the shorter beard of juvenile bearded vultures is much less conspicuous.
The subspecies of Gypaetus barbatus have defining physical appearances as adults that distinguish them from one another. Gypaetus barbatus barbatus possesses joined black eye-patches, black face-streaks, a partially or fully black gorget, and a completely feathered tarsi. Gypaetus barbatus aureus is slightly larger and more prominently marked than its northwest African relative. Gypaetus barbatus meridionalis is on average smaller than Gypaetus barbatus barbatus, lacks the face-streaks, gorget, and joined eye patches, and has 4 to 5 cm of the tarsi left unfeathered. (Ferguson-Lees and Christie, 2001)
Bearded vultures are mostly monogamous, though polyandrous trios can be found commonly in the Pyrenees mountain range of Spain and France. Unpaired or free-floating males will often join a pre-existing male and female pair, creating a trio. This behavior increases population densities of bearded vultures, which may be responsible for delayed maturity in wild bearded vultures. The formation of polyandrous trios in bearded vultures has also led to intrasexual competition between males. These intrasexual aggressions lower the frequency of heterosexual copulations during the fertile period. However, aggression tends to decrease within a trio over time. (Antor, et al., 2007; Bertran, et al., 2009; Ferguson-Lees and Christie, 2001)
Pairs of bearded vultures engage in copulations between 50 and 90 days before egg laying. Males tend to copulate with females more frequently in the evening after foraging for prey or bones. This may be a form of sperm competition, with individual males fighting to be the last to copulate with a female. Reverse mounting is common among polyandrous trios. After the alpha male drives off the beta male, he is mounted by the female. (Bertran and Margalida, 1999; Bertran and Margalida, 2006)
Female bearded vultures in polyandrous trios prefer to mate with alpha males, but will also mate with beta males. Mating with a larger number of males may benefit the female by providing her with more parental care for her young. Extra-pair copulations may be a way to increase the likelihood of successful nesting if the first male is infertile, or may increase genetic diversity within the brood. Females may also mate with both males to avoid harassment or aggression. (Bertran, et al., 2009)
The breeding period of Gypaetus barbatus occurs from October until July. When breeding in the wild, males are an average of 8.9 years old, while females are about 7.7 years old. Nest building starts about 111 days before egg-laying. Female bearded vultures lay one to three eggs per breeding cycle, with usually only one egg surviving. In the Pyrenean population, there is extremely low breeding productivity with only an average of 0.4 fledglings per pair per year. Egg laying to fledgling lasts about 177 days. Incubation lasts approximately 54 days, starting when the first egg has been laid. There is a large variation in the first flight time of chicks, though most leave at about 4 months after birth, at which point they permanently leave the nest. (Antor, et al., 2007; Margalida, et al., 2003)
Breeding success of Gypaetus barbatus may be influenced by interactions between heterospecifics. Bearded vultures must actively defend their nests from kleptoparasitism, resulting in a negative energy cost and less energy to dedicate to young. Relocating nests to avoid attacks could lead to nesting at altitudes or locations with poor weather conditions, or in closer proximity to humans. (Bertran and Margalida, 2004; Margalida and Bertran, 2005; Margalida, et al., 2003)
Breeding pairs of Gypaetus barbatus have several nests within a single territory, and rotate between them on a yearly basis. Males tend to more actively build nests and defend territories, while females allocate more time and energy tending to the nest. However, both males and females display territorial behavior around the nest against other bearded vultures and heterospecifics. (Margalida and Bertran, 2005; Margalida, et al., 2003)
The breeding cycle is divided into three periods: pre-laying, incubation, and chick-rearing. Nest defense versus conspecifics occurs primarily during the pre-laying period. This may be due to intrasexual competition between males, or food competition. During this period, males attack invaders more frequently than females. This may be so females do not expend excess energy to have more available for mating. Females may also be able to assess the quality and breeding potential of a male through his ability to defend his territory and build a nest. (Margalida and Bertran, 2005; Margalida, et al., 2003; Margalida, et al., 2004)
Unlike other vultures, bearded vultures deliver prey remains to their young without regurgitation. Mean hatching asynchrony between eggs in Gypaetus barbatus is estimated to be six days, longer than in any other raptor. The first chick is usually larger, more active, has a more erect posture, and can call more insistently than the second chick. Parental favoritism towards the first chick is common among bearded vultures, and parents may only feed the first born. The second chick often dies very quickly, and is frequently fed to the first chick for nourishment. The poor ability of the second chick to fend for itself may be an adaptation to a quick death if the first chick survives. At the same time, the second egg may act as insurance in case the first does not survive. Chicks are born semi-altricial and require post-hatching incubation and feeding. Both parents participate in feeding and rearing their chick. (Margalida and Bertran, 2005; Margalida, et al., 2003; Margalida, et al., 2009a)
Most bearded vultures are monogamous and heterosexual, but male-male mounting has been recorded within polyandrous trios. This homosexual behavior is not directly correlated with different forms of intrasexual competition such as sperm competition or hierarchical dominance. As there is no correlation between dominance and mounting behavior, male bearded vultures in polyandrous trios most likely mount one another to regulate levels of aggression. (Bertran and Margalida, 2003; Bertran and Margalida, 2006)
Bearded vultures are diurnal and often can be seen performing aerial displays such as mutual circling and high-speed chases. They roll over one another, displaying their talons and diving nearly completely to the ground. Bearded vultures also perform sky dances, ascending to high altitudes and rapidly diving down, twisting and rolling past the nesting site. It is hypothesized that young birds performing these chases and dives might be engaging in social play to practice courtship skills. Practicing these skills as a juvenile may also be important for G. barbatus in defending nests from heterospecifics when they reach maturity. (Blumstein, 1990; Ferguson-Lees and Christie, 2001)
Bearded vultures have extremely large home territories that range from 250 to 700 square kilometers. Foraging areas of Gypaetus barbatus have been reported to be as large as 7,500 square kilometers. (Margalida, 2008)
Bearded vultures are rarely vocal birds. However, during mating, they often make loud chuckling noises. During courtship displays, bearded vultures are reported to emit a sharp, guttural "koolik, koolik", as well as twittering shrill-like noises. They also frequently use aerial displays and chases to communicate territory boundaries, and to defend or attract mates. They are considered Old World vultures, and like other vultures of this group they have a poorly developed sense of smell. These birds rely heavily on excellent eyesight to locate carcasses. Like all birds, bearded vultures perceive their environments through visual, tactile, auditory and chemical stimuli. (Blumstein, 1990; Ferguson-Lees and Christie, 2001)
Gypaetus barbatus are strictly carnivorous but have a unique diet consisting mainly of bones. Like many other vultures they are scavengers, preying on the carcasses of dead animals. Deceased mammals account for 93% of their diets, with 61% being medium-sized ungulates. G. barbatus is also known to prey on tortoises and various species of birds. (Ferguson-Lees and Christie, 2001; Margalida, et al., 2009b)
The diet of G. barbatus consists exclusively of bones (85%) and carrion. They prefer to feed on bones as adults, though scraps of meat or skin are an important part of the diet for chicks. Bearded vultures have an extremely high acid content of the stomach that allows them to digest bones within a 24 hour period. Bones eaten can be up to 10 cm in diameter, and can weigh up to 4 kg. Large bones are picked up by their talons, lifted up 50 to 150 m in the air, and carried over to rocky bone-dropping sites called ossuaries. Here they are dropped repeatedly until they break open and bone marrow can be consumed. Bearded vultures use similar techniques to kill tortoises, small birds, and smaller mammal prey such as marmots and hares. Bearded vultures often trap larger ungulates near the edges of cliffs and force them to fall off by the vigorous beating of their wings. (Ferguson-Lees and Christie, 2001; Margalida, 2008)
Bearded vultures prefer fatty bones, which have a higher percentage of oleic acid than non-fatty bones, and are associated with optimizing both time spent foraging and energy use. Once they locate a carcass, bearded vultures often wait for other, meat-eating scavengers to pick the bones clean before feeding. (Margalida, 2008)
The technique of feeding and conspicuous nesting sites of bearded vultures make chicks vulnerable to kleptoparasitism. They have aggressive interactions with common ravens, golden eagles, griffon vultures and other bearded vultures. Bearded vultures are very territorial and use aerial attacks to defend their nests from competitors. As a result, there is a negative energy cost on bearded vultures, especially during the early breeding periods when fledglings are young. (Bertran and Margalida, 2004; Margalida and Bertran, 2005)
As feeders on carrion, bearded vultures dispose of rotting remains and help keep the ecosystem clear of disease. Bearded vultures will wait patiently at a cliff edge until other scavengers have finished eating, and will not compete for food. As a result, they often feed on older carcasses and offal, clearing even the least desirable remains other scavengers would not eat. (Ferguson-Lees and Christie, 2001)
As carrion scavengers, Gypaetus barbatus contribute to rotting carcass removal and help control disease within ecosystems.
There are no adverse effects of Gypaetus barbatus on humans. Unfortunately, as bearded vultures were often seen carrying large animal bones, they were assumed to kill farmers' livestock. An old, common name for these birds is "Lammergeier" which comes from a German word meaning "lamb-vulture." Many birds have been, and continue to be, persecuted for this assumption despite their scavenging habits.
Population densities of bearded vultures are very low, as they can occupy massive ranges. In all three continents, the range of bearded vultures has decreased tremendously, particularly in Europe. Potential reasons for this include illegal poisoning of baits set for carnivores, degradation of habitats, and disturbance in breeding areas. Bearded vultures in Europe are considered endangered, with less than 150 territories remaining in the European Union in 2007, and are currently being reintroduced in the Pyrenees and the Alps. However, because of the extremely large range of these birds, they are of least concern (LC) on the IUCN list for threatened species. (Birdlife International 2009, 2010; Margalida, et al., 2009b)
Jonathan Tenenzapf (author), University of Michigan-Ann Arbor, Phil Myers (editor), University of Michigan-Ann Arbor, Rachelle Sterling (editor), Special Projects.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
uses sound to communicate
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
helps break down and decompose dead plants and/or animals
an animal that mainly eats meat
flesh of dead animals.
uses smells or other chemicals to communicate
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
parental care is carried out by males
Having one mate at a time.
having the capacity to move from one place to another.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
the area in which the animal is naturally found, the region in which it is endemic.
found in the oriental region of the world. In other words, India and southeast Asia.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).
an animal that mainly eats dead animals
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
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