Post by OldGreenVulture on Sept 26, 2019 5:22:08 GMT
Wandering Albatross - Diomedea Exulans.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Procellariiformes
Family: Diomedeidae
Genus: Diomedea
Species: Diomedea exulans
The bird with the largest wingspan in the world!
Geographic Range
Wandering albatrosses are found almost exclusively in the Southern Hemisphere, although occasional sightings just north of the Equator have been reported. (Birdlife International, 2006; Shirihai, 2002)
There is some disagreement over how many subspecies of wandering albatross (Diomedea exulans) there are, and whether they should be considered separate species. Most subspecies of Diomedea exulans are difficult to tell apart, especially as juveniles, but DNA analyses have shown that significant differences exist. (Birdlife International, 2006; Shirihai, 2002)
Diomedea exulans exulans breeds on South Georgia, Prince Edward, Marion, Crozet, Kerguelen, and Macquarie islands. Diomedea exulans dabbenena occurs on Gough and Inaccessible islands, ranging over the Atlantic Ocean to western coastal Africa. Diomedea exulans antipodensis is found primarily on the Antipodes of New Zealand, and ranges at sea from Chile to eastern Australia. Diomedea exulans amsterdamensis is found only on Amsterdam Island and the surrounding seas. Other subspecies names that have become obsolete include Diomedea exulans gibsoni, now commonly considered part of D. e. antipodensis, and Diomedea exulans chionoptera, considered part of D. e. exulans. (Birdlife International, 2006; Shirihai, 2002)
Habitat
Wandering albatrosses breed on several subantarctic islands, which are characterized by peat soils, tussock grass, sedges, mosses, and shrubs. Wandering albatrosses nest in sheltered areas on plateaus, ridges, plains, or valleys.
Outside of the breeding season, wandering albatrosses are found only in the open ocean, where food is abundant. (Birdlife International, 2006; Shirihai, 2002)
Physical Description
Mass : 8130 g (average) (286.18 oz)
Length : 1.10 to 1.35 m (3.61 to 4.43 ft)
Wingspan : 2.50 to 3.50 m; avg. 3.10 m (8.2 to 11.48 ft; avg. 10.17 ft)
All subspecies of wandering albatrosses have extremely long wingspans (averaging just over 3 meters), white underwing coverts, and pink bills. Adult body plumage ranges from pure white to dark brown, and the wings range from being entirely blackish to a combination of black with white coverts and scapulars. They are distinguished from the closely related royal albatross by their white eyelids, pink bill color, lack of black on the maxilla, and head and body shape. On average, males have longer bills, tarsi, tails, and wings than females. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Juveniles of all subspecies are very much alike; they have chocolate-brown plumage with a white face and black wings. As individuals age, most become progressively whiter with each molt, starting with the back. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
D. e. exulans averages larger than other recognized subspecies, and is the only taxon that achieves fully white body plumage, and this only in males. Although females do not become pure white, they can still be distinguished from other subspecies by color alone. Adults also have mostly white coverts, with black only on the primaries and secondaries. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Adults of D. e. amsterdamensis have dark brown plumage with white faces and black crowns, and are distinguished from juveniles by their white bellies and throats. In addition to their black tails, they also have a black stripe along the cutting edge of the maxilla, a character otherwise found in D. epomophora but not other forms of D. exulans. Males and females are similar in plumage. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Adults of D. e. antipodensis display sexual dimorphism in plumage, with older males appearing white with some brown splotching, while adult females have mostly brown underparts and a white face. Both sexes also have a brown breast band. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
With age, D. e. dabbenena gradually attains white plumage, although it never becomes as white as male D. e. exulans. The wing coverts also appear mostly black, although there may be white patches. Females have more brown splotches than males, and have less white in their wing coverts. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Reproduction
Breeding interval : Breeding occurs biennially, possibly annually if the previous season's attempt fails.
Breeding season : Breeding occurs from December through March.
Eggs per season : 1 (average)
Time to hatching : 74 to 85 days
Time to fledging : 7 to 10 months
Time to independence : 7 to 10 months
Age at sexual or reproductive maturity (female) : 6 to 22 years; avg. 10 years
Age at sexual or reproductive maturity (male) : 6 to 22 years; avg. 10 years
Wandering albatrosses have a biennial breeding cycle, and pairs with chicks from the previous season co-exist in colonies with mating and incubating pairs. Pairs unsuccessful in one year may try to mate again in the same year or the next one, but their chances of successfully rearing young are low. (Shirihai, 2002; Tickell, 1968)
After foraging at sea, males arrive first at the same breeding site every year within days of each other. They locate and reuse old nests or sometimes create new ones. Females arrive later, over the course of a few weeks. Wandering albatrosses have a monogamous mating strategy, forming pair bonds for life. Females may bond temporarily with other males if their partner and nest are not readily visible. (Shirihai, 2002; Tickell, 1968)
Copulation occurs in the austral summer, usually around December (February for D. e. amsterdamensis). Rape and extra-pair copulations are frequent, despite their monogamous mating strategy. Pairs nest on slopes or valleys, usually in the cover of grasses or shrubs. Nests are depressions lined with grass, twigs, and soil. A single egg is laid and, if incubation or rearing fails, pairs usually wait until the following year to try again. Both parents incubate eggs, which takes about 78 days on average. Although females take the first shift, males are eager to take over incubation and may forcefully push females off the egg. Untended eggs are in danger of predation by skuas (Stercorarius) and sheathbills (Chionis). (Shirihai, 2002; Tickell, 1968)
After the chick hatches, they are brooded for about 4 to 6 weeks until they can be left alone at the nest. Males and females alternate foraging at sea. Following the brooding period, both parents leave the chick by itself while they forage. The chicks are entirely dependent on their parents for food for 9 to 10 months, and may wait weeks for them to return. Chicks are entirely independent once they fledge. (Shirihai, 2002; Tickell, 1968)
Some individuals may reach sexual maturity by age 6. Immature, non-breeding individuals will return to the breeding site. Group displays are common among non-breeding adults, but most breeding adults do not participate. (Shirihai, 2002; Tickell, 1968)
Males choose the nesting territory, and stay at the nest site more than females before incubation. Parents alternate during incubation, and later during brooding and feeding once the chick is old enough to be left alone at the nest. Although there is generally equal parental investment, males will tend to invest more as the chick nears fledging. Occasionally, a single parent may successfully rear its chick. (Shirihai, 2002; Tickell, 1968)
Lifespan/Longevity
Extreme lifespan (wild) : 60 years (high)
Average lifespan (wild) :415 months
Wandering albatrosses are long-lived. An individual nicknamed "Grandma" was recorded to live over 60 years in New Zealand. Due to the late onset of maturity, with the average age at first breeding about 10 years, such longevity is not unexpected. However, there is fairly high chick mortality, ranging from 30 to 75%. Their slow breeding cycle and late onset of maturity make wandering albatrosses highly susceptible to population declines when adults are caught as bycatch in fishing nets. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Behavior
Territory Size : 1 m^2 (average)
While foraging at sea, wandering albatrosses travel in small groups. Large feeding frenzies may occur around fishing boats. Individuals may travel thousands of kilometers away from their breeding grounds, even occasionally crossing the equator.
During the breeding season, Wandering albatrosses are gregarious and displays are common (see “Communication and Perception” section, below). Vocalizations and displays occur during mating or territorial defense. (Shirihai, 2002; Tickell, 1968)
Home Range
Wandering albatrosses defend small nesting territories, otherwise the range within which they travel is many thousands of square kilometers. (Shirihai, 2002; Tickell, 1968)
Communication and Perception
Displays and vocalizations are common when defending territory or mating. They include croaks, bill-clapping, bill-touching, skypointing, trumpeting, head-shaking, the "ecstatic" gesture, and "the gawky-look". Individuals may also vocalize when fighting over food. (Shirihai, 2002)
Food Habits
Wandering albatrosses primarily eat fish, such as toothfish (Dissostichus), squids, other cephalopods, and occasional crustaceans. The primary method of foraging is by surface-seizing, but they have the ability to plunge and dive up to 1 meter. They will sometimes follow fishing boats and feed on catches with other Procellariiformes, which they usually outcompete because of their size. (Birdlife International, 2006; Shirihai, 2002)
Predation
Known predators :
skuas (Stercorariidae)
sheathbills (Chionis)
domestic cats (Felis silvestris)
introduced pigs (Sus scrofa)
introduced goats (Capra hircus)
introduced rats (Rattus rattus and Rattus norvegicus)
introduced mice (Mus musculus)
Although humans formerly hunted wandering albatrosses as food, adults currently have no predators. Their large size, sharp bill, and occasionally aggressive behavior make them undesirable opponents. However, some are inadvertently caught during large-scale fishing operations.
Chicks and eggs, on the other hand, are susceptible to predation from skuas and sheathbills, and formerly were harvested by humans as well. Eggs that fall out of nests or are unattended are quickly preyed upon. Nests are frequently sheltered with plant material to make them less conspicuous. Small chicks that are still in the brooding stage are easy targets for large carnivorous seabirds. Introduced predators, including mice, pigs, cats, rats, and goats are also known to eat eggs and chicks. (Birdlife International, 2006; IUCN, 2006; Shirihai, 2002; Tickell, 1968)
Ecosystem Roles
Wandering albatrosses are predators, feeding on fish, cephalopods, and crustaceans. They are known for their ability to compete with other seabirds for food, particularly near fishing boats. Although adult birds, their eggs, and their chicks were formerly a source of food to humans, such practices have been stopped. (IUCN, 2006; Shirihai, 2002)
Economic Importance for Humans: Negative
Wandering albatrosses, along with other seabirds, follow fishing boats to take advantage of helpless fish and are reputed to reduce economic output from these fisheries. Albatrosses also become incidental bycatch, hampering conservation efforts. (Birdlife International, 2006; IUCN, 2006; Shirihai, 2002)
Economic Importance for Humans: Positive
Wandering albatrosses have extraordinary morphology, with perhaps the longest wingspan of any bird. Their enormous size also makes them popular in ecotourism excursions, especially for birders. Declining population numbers also mean increased conservation efforts. Their relative tameness towards humans makes them ideal for research and study. (Shirihai, 2002)
Ways that people benefit from these animals:
ecotourism ; research and education.
Conservation Status
IUCN Red List: Vulnerable.
US Migratory Bird Act: No special status.
US Federal List: No special status.
CITES: No special status.
Diomedea exulans exulans and Diomedea exulans antipodensis are listed by the IUCN Red list and Birdlife International as being vulnerable; Diomedea exulans dabbenena is listed as endangered, and Diomedea exulans amsterdamensis is listed as critically endangered.
All subspecies of Diomedea exulans are highly vulnerable to becoming bycatch of commercial fisheries, and population declines are mostly attributed to this. Introduced predators such as feral cats, pigs, goats, and rats on various islands leads to high mortality rates of chicks and eggs. Diomedea exulans amsterdamensis is listed as critically endangered due to introduced predators, risk of becoming bycatch, small population size, threat of chick mortality by disease, and loss of habitat to cattle farming.
Some conservation measures that have been taken include removal of introduced predators from islands, listing breeding habitats as World Heritage Sites, fishery relocation, and population monitoring. (Birdlife International, 2006; IUCN, 2006; Shirihai, 2002)
References
Birdlife International, 2006. "Species factsheets" (On-line). www.birdlife.org.
IUCN, 2006. "2006 IUCN Red List of Threatened Species" (On-line). www.iucnredlist.org.
Shirihai, H. 2002. The Complete Guide to Antarctic Wildlife. New Jersey: Princeton University Press.
Tickell, W. 1968. Biology of Great Albatrosses. Pp. 1-53 in Antarctic Bird Studies. Baltimore: Horn-Schafer.
animaldiversity.ummz.umich.edu/site/accounts/information/Diomedea_exulans.html
Originally from Carnivora.
carnivora.net/wandering-albatross-diomedea-exulans-t1535.html#p2678
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Procellariiformes
Family: Diomedeidae
Genus: Diomedea
Species: Diomedea exulans
The bird with the largest wingspan in the world!
Geographic Range
Wandering albatrosses are found almost exclusively in the Southern Hemisphere, although occasional sightings just north of the Equator have been reported. (Birdlife International, 2006; Shirihai, 2002)
There is some disagreement over how many subspecies of wandering albatross (Diomedea exulans) there are, and whether they should be considered separate species. Most subspecies of Diomedea exulans are difficult to tell apart, especially as juveniles, but DNA analyses have shown that significant differences exist. (Birdlife International, 2006; Shirihai, 2002)
Diomedea exulans exulans breeds on South Georgia, Prince Edward, Marion, Crozet, Kerguelen, and Macquarie islands. Diomedea exulans dabbenena occurs on Gough and Inaccessible islands, ranging over the Atlantic Ocean to western coastal Africa. Diomedea exulans antipodensis is found primarily on the Antipodes of New Zealand, and ranges at sea from Chile to eastern Australia. Diomedea exulans amsterdamensis is found only on Amsterdam Island and the surrounding seas. Other subspecies names that have become obsolete include Diomedea exulans gibsoni, now commonly considered part of D. e. antipodensis, and Diomedea exulans chionoptera, considered part of D. e. exulans. (Birdlife International, 2006; Shirihai, 2002)
Habitat
Wandering albatrosses breed on several subantarctic islands, which are characterized by peat soils, tussock grass, sedges, mosses, and shrubs. Wandering albatrosses nest in sheltered areas on plateaus, ridges, plains, or valleys.
Outside of the breeding season, wandering albatrosses are found only in the open ocean, where food is abundant. (Birdlife International, 2006; Shirihai, 2002)
Physical Description
Mass : 8130 g (average) (286.18 oz)
Length : 1.10 to 1.35 m (3.61 to 4.43 ft)
Wingspan : 2.50 to 3.50 m; avg. 3.10 m (8.2 to 11.48 ft; avg. 10.17 ft)
All subspecies of wandering albatrosses have extremely long wingspans (averaging just over 3 meters), white underwing coverts, and pink bills. Adult body plumage ranges from pure white to dark brown, and the wings range from being entirely blackish to a combination of black with white coverts and scapulars. They are distinguished from the closely related royal albatross by their white eyelids, pink bill color, lack of black on the maxilla, and head and body shape. On average, males have longer bills, tarsi, tails, and wings than females. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Juveniles of all subspecies are very much alike; they have chocolate-brown plumage with a white face and black wings. As individuals age, most become progressively whiter with each molt, starting with the back. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
D. e. exulans averages larger than other recognized subspecies, and is the only taxon that achieves fully white body plumage, and this only in males. Although females do not become pure white, they can still be distinguished from other subspecies by color alone. Adults also have mostly white coverts, with black only on the primaries and secondaries. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Adults of D. e. amsterdamensis have dark brown plumage with white faces and black crowns, and are distinguished from juveniles by their white bellies and throats. In addition to their black tails, they also have a black stripe along the cutting edge of the maxilla, a character otherwise found in D. epomophora but not other forms of D. exulans. Males and females are similar in plumage. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Adults of D. e. antipodensis display sexual dimorphism in plumage, with older males appearing white with some brown splotching, while adult females have mostly brown underparts and a white face. Both sexes also have a brown breast band. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
With age, D. e. dabbenena gradually attains white plumage, although it never becomes as white as male D. e. exulans. The wing coverts also appear mostly black, although there may be white patches. Females have more brown splotches than males, and have less white in their wing coverts. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Reproduction
Breeding interval : Breeding occurs biennially, possibly annually if the previous season's attempt fails.
Breeding season : Breeding occurs from December through March.
Eggs per season : 1 (average)
Time to hatching : 74 to 85 days
Time to fledging : 7 to 10 months
Time to independence : 7 to 10 months
Age at sexual or reproductive maturity (female) : 6 to 22 years; avg. 10 years
Age at sexual or reproductive maturity (male) : 6 to 22 years; avg. 10 years
Wandering albatrosses have a biennial breeding cycle, and pairs with chicks from the previous season co-exist in colonies with mating and incubating pairs. Pairs unsuccessful in one year may try to mate again in the same year or the next one, but their chances of successfully rearing young are low. (Shirihai, 2002; Tickell, 1968)
After foraging at sea, males arrive first at the same breeding site every year within days of each other. They locate and reuse old nests or sometimes create new ones. Females arrive later, over the course of a few weeks. Wandering albatrosses have a monogamous mating strategy, forming pair bonds for life. Females may bond temporarily with other males if their partner and nest are not readily visible. (Shirihai, 2002; Tickell, 1968)
Copulation occurs in the austral summer, usually around December (February for D. e. amsterdamensis). Rape and extra-pair copulations are frequent, despite their monogamous mating strategy. Pairs nest on slopes or valleys, usually in the cover of grasses or shrubs. Nests are depressions lined with grass, twigs, and soil. A single egg is laid and, if incubation or rearing fails, pairs usually wait until the following year to try again. Both parents incubate eggs, which takes about 78 days on average. Although females take the first shift, males are eager to take over incubation and may forcefully push females off the egg. Untended eggs are in danger of predation by skuas (Stercorarius) and sheathbills (Chionis). (Shirihai, 2002; Tickell, 1968)
After the chick hatches, they are brooded for about 4 to 6 weeks until they can be left alone at the nest. Males and females alternate foraging at sea. Following the brooding period, both parents leave the chick by itself while they forage. The chicks are entirely dependent on their parents for food for 9 to 10 months, and may wait weeks for them to return. Chicks are entirely independent once they fledge. (Shirihai, 2002; Tickell, 1968)
Some individuals may reach sexual maturity by age 6. Immature, non-breeding individuals will return to the breeding site. Group displays are common among non-breeding adults, but most breeding adults do not participate. (Shirihai, 2002; Tickell, 1968)
Males choose the nesting territory, and stay at the nest site more than females before incubation. Parents alternate during incubation, and later during brooding and feeding once the chick is old enough to be left alone at the nest. Although there is generally equal parental investment, males will tend to invest more as the chick nears fledging. Occasionally, a single parent may successfully rear its chick. (Shirihai, 2002; Tickell, 1968)
Lifespan/Longevity
Extreme lifespan (wild) : 60 years (high)
Average lifespan (wild) :415 months
Wandering albatrosses are long-lived. An individual nicknamed "Grandma" was recorded to live over 60 years in New Zealand. Due to the late onset of maturity, with the average age at first breeding about 10 years, such longevity is not unexpected. However, there is fairly high chick mortality, ranging from 30 to 75%. Their slow breeding cycle and late onset of maturity make wandering albatrosses highly susceptible to population declines when adults are caught as bycatch in fishing nets. (Birdlife International, 2006; Shirihai, 2002; Tickell, 1968)
Behavior
Territory Size : 1 m^2 (average)
While foraging at sea, wandering albatrosses travel in small groups. Large feeding frenzies may occur around fishing boats. Individuals may travel thousands of kilometers away from their breeding grounds, even occasionally crossing the equator.
During the breeding season, Wandering albatrosses are gregarious and displays are common (see “Communication and Perception” section, below). Vocalizations and displays occur during mating or territorial defense. (Shirihai, 2002; Tickell, 1968)
Home Range
Wandering albatrosses defend small nesting territories, otherwise the range within which they travel is many thousands of square kilometers. (Shirihai, 2002; Tickell, 1968)
Communication and Perception
Displays and vocalizations are common when defending territory or mating. They include croaks, bill-clapping, bill-touching, skypointing, trumpeting, head-shaking, the "ecstatic" gesture, and "the gawky-look". Individuals may also vocalize when fighting over food. (Shirihai, 2002)
Food Habits
Wandering albatrosses primarily eat fish, such as toothfish (Dissostichus), squids, other cephalopods, and occasional crustaceans. The primary method of foraging is by surface-seizing, but they have the ability to plunge and dive up to 1 meter. They will sometimes follow fishing boats and feed on catches with other Procellariiformes, which they usually outcompete because of their size. (Birdlife International, 2006; Shirihai, 2002)
Predation
Known predators :
skuas (Stercorariidae)
sheathbills (Chionis)
domestic cats (Felis silvestris)
introduced pigs (Sus scrofa)
introduced goats (Capra hircus)
introduced rats (Rattus rattus and Rattus norvegicus)
introduced mice (Mus musculus)
Although humans formerly hunted wandering albatrosses as food, adults currently have no predators. Their large size, sharp bill, and occasionally aggressive behavior make them undesirable opponents. However, some are inadvertently caught during large-scale fishing operations.
Chicks and eggs, on the other hand, are susceptible to predation from skuas and sheathbills, and formerly were harvested by humans as well. Eggs that fall out of nests or are unattended are quickly preyed upon. Nests are frequently sheltered with plant material to make them less conspicuous. Small chicks that are still in the brooding stage are easy targets for large carnivorous seabirds. Introduced predators, including mice, pigs, cats, rats, and goats are also known to eat eggs and chicks. (Birdlife International, 2006; IUCN, 2006; Shirihai, 2002; Tickell, 1968)
Ecosystem Roles
Wandering albatrosses are predators, feeding on fish, cephalopods, and crustaceans. They are known for their ability to compete with other seabirds for food, particularly near fishing boats. Although adult birds, their eggs, and their chicks were formerly a source of food to humans, such practices have been stopped. (IUCN, 2006; Shirihai, 2002)
Economic Importance for Humans: Negative
Wandering albatrosses, along with other seabirds, follow fishing boats to take advantage of helpless fish and are reputed to reduce economic output from these fisheries. Albatrosses also become incidental bycatch, hampering conservation efforts. (Birdlife International, 2006; IUCN, 2006; Shirihai, 2002)
Economic Importance for Humans: Positive
Wandering albatrosses have extraordinary morphology, with perhaps the longest wingspan of any bird. Their enormous size also makes them popular in ecotourism excursions, especially for birders. Declining population numbers also mean increased conservation efforts. Their relative tameness towards humans makes them ideal for research and study. (Shirihai, 2002)
Ways that people benefit from these animals:
ecotourism ; research and education.
Conservation Status
IUCN Red List: Vulnerable.
US Migratory Bird Act: No special status.
US Federal List: No special status.
CITES: No special status.
Diomedea exulans exulans and Diomedea exulans antipodensis are listed by the IUCN Red list and Birdlife International as being vulnerable; Diomedea exulans dabbenena is listed as endangered, and Diomedea exulans amsterdamensis is listed as critically endangered.
All subspecies of Diomedea exulans are highly vulnerable to becoming bycatch of commercial fisheries, and population declines are mostly attributed to this. Introduced predators such as feral cats, pigs, goats, and rats on various islands leads to high mortality rates of chicks and eggs. Diomedea exulans amsterdamensis is listed as critically endangered due to introduced predators, risk of becoming bycatch, small population size, threat of chick mortality by disease, and loss of habitat to cattle farming.
Some conservation measures that have been taken include removal of introduced predators from islands, listing breeding habitats as World Heritage Sites, fishery relocation, and population monitoring. (Birdlife International, 2006; IUCN, 2006; Shirihai, 2002)
References
Birdlife International, 2006. "Species factsheets" (On-line). www.birdlife.org.
IUCN, 2006. "2006 IUCN Red List of Threatened Species" (On-line). www.iucnredlist.org.
Shirihai, H. 2002. The Complete Guide to Antarctic Wildlife. New Jersey: Princeton University Press.
Tickell, W. 1968. Biology of Great Albatrosses. Pp. 1-53 in Antarctic Bird Studies. Baltimore: Horn-Schafer.
animaldiversity.ummz.umich.edu/site/accounts/information/Diomedea_exulans.html
Originally from Carnivora.
carnivora.net/wandering-albatross-diomedea-exulans-t1535.html#p2678