Albatrosses

(Diomedeidae)

Class: Aves

Order: Procellariiformes

Family: Diomedeidae

Thumbnail description
The largest flying seabirds, with exceptionally long narrow wings adapted for gliding and distinctive hooked bill and plumage ranging from all dark to mostly white

Size
Wingspan 62.3–106 in (190–323 cm); 3.74–26.25 lb (1.7–11.9 kg); length: 20–80 in (50–200 cm)

Number of genera, species
4 genera; 14 species

Habitat
Oceanic, generally only approach land for breeding on remote islands

Conservation status
Critically Endangered: 1 species; Vulnerable: 8 species; Lower Risk: 4 species; Data Deficient: 1 species.

Distribution
The north and south Pacific, Indian, and south Atlantic oceans

Evolution and systematics

A range of fossil albatrosses are evidence of a wider and more cosmopolitan distribution than those extant today. The earliest identified are from the Oligocene in Germany and South Carolina. Species approaching the characteristics of modern albatrosses are from the Northern Hemisphere (Europe and both coasts of North America) in the Miocene and Pliocene, but deposits are known from Australia, South Africa and Argentina in the predominantly marine Southern Hemisphere. Albatrosses were probably widespread in the north Atlantic until the late Tertiary.

The taxonomic status of albatrosses was fragmented and confusing until long-term field studies started during the 1930s. The collation of morphological, biological, and distribution data from breeding locations, with various genetic analyses from the 1990s, suggests a division into 4 genera and 24 taxa, a term that applies to both the species and subspecies of this order (Phoebastria with three taxa; Diomedea, 7 taxa; Thalassarche, 12 taxa; and Phoebetria, two taxa). Most of the 24 recognizable taxa (by combined morphology and genetics) may warrant species status and can be considered as distinct conservation units. In this treatment, however, the more traditional count of two genera will be applied: Diomedidae, which encompasses the proposed genera Phoebastria and Thalassarche; and Phoebetria, the two species of sooty albatross. A more positive resolution of the species question awaits data from poorly studied species in remote locations.

Physical characteristics

The great albatrosses (Diomedea) are the largest, with wingspans that can exceed 9.8 ft (300 cm). They lack a dark back except as juveniles. All have a white underwing. The upper wing of the northern royal albatross (D. epomophora sanfordi) is always black, while that of the wandering albatross (D. exulans) and the southern royal albatross (D. epomophora) grow increasingly white with age, especially among males. When Antipodean (D. antipodensis) and Amsterdam albatrosses (D. amsterdamensis) breed, especially females, they are almost as dark as in as juveniles. In the wandering royal albatross (D. exulans), Tristan albatross (D. dabbenena) and Gibson's albatross (D. gibsoni), body plumage whitens with age, and females may retain dark markings on the chest, flank, and back. Otherwise the body is chiefly white in the royal and northern royal albatrosses. The long (5.5–7.5 in; 140–190 mm) pale, horn-colored bill has a distinctively hooked tip, and it flushes pink in adults rearing chicks.

The Northern Pacific albatrosses include four medium to small taxa with wingspans of 6.2–7.9 ft (190–240 cm), and all have short, black tails. The two largest, i.e. the short-tailed albatross (D. albatrus) and the waved albatross (D. irrorata), have distinctive yellow/golden plumage on the head and nape. Of the two smallest, the Laysan albatross (D. immutabilis) has a pinkish bill, white body, and dark upper wing, while the black-footed albatross (D. nigripes) has a black bill and is mainly dark brown, except for a white patch at the rump and a variably pale face.

The mollymawks, which include 11 small to medium size taxa, are the most diverse group of albatrosses with wingspans of 5.9–8.4 ft (180–256 cm). All have black upper wings and back, variable amounts of black on the underwing, and white body. All have a variable gray eyebrow with heads and necks varying from mainly white to dark gray, some with pronounced paler cap. The shy albatross, white-capped albatross, Salvin's, and Chatham mollymawk (D. cauta, D. cauta cauta, D. salvini and D. cauta eremita) all have chiefly white underwings, while all others have variable amounts of black reaching into the underwing from the leading edge. All mollymawks have distinctive bill structures and colors which, when combined with head color, help identification. The black-browed mollymawk (D. melanophris) and the Campbell black-browed mollymawk (D. impavida) have golden yellow bills with pink tips. The gray-headed mollymawk (D. chrysostoma) has a dark gray head and bill, with a yellow culmen and pink nail, yellow lower mandible stripe and black intervening sides to the bill. Buller's mollymawk (D. bulleri) and the Pacific mollymawk (D. platei) have similar bills without the pink nail and have gray, with paler-capped, heads. The smallest mollymawks (D. chlororhynchos) have a gray washed head, and the eastern yellow-nosed mollymawk (D. bassi) has a chiefly white head. Both taxa have bills with a yellow culmen stripe and pink nail. All mollymawks have a colorful pink/orange fleshy facial stripe from gape to ear which is exposed during displays.

The two sooty albatrosses (Phoebetria), with a wing span of 6.0–7.15 ft (183–218 cm), and the longest and most pointed tails of all albatross taxa, have mainly dark bills, plumage, and legs. However, the light-mantled sooty albatross (P. palpebrata), normally has a paler brown mantle than the dark-mantled sooty albatross (P. fusca).

Distribution

Three albatrosses, namely the short-tailed, the Laysan, and the black-footed, are confined to the northern Pacific ocean. The waved albatross is tropical, mainly found from the Galápagos Islands to the coasts of Ecuador and Peru. All other albatrosses are found in the Southern Hemisphere in a circumpolar band mainly from 65°S to 20°S, but north to 15°S on the coast of southern Africa and 5°S on the west coast of South America.

Habitat

More than 70% of an albatross' life is spent on or over the ocean, while foraging, migrating, or resting. With the exception of the waved albatross, albatrosses avoid the relatively windless tropical doldrums. Though ranging widely at sea from breeding islands and during non-breeding time, significant differences in distribution can occur within and between species or between sexes. Some species are found to forage locally over continental shelves, while others roam widely to obtain food. Significant concentrations of birds can be found in areas of ocean richness near major currents, gyres and upwellings around South America (e.g. Humbolt current), Australia, New Zealand, South Africa (Benguela current) and in the north Pacific (Bering Sea and Gulf of Alaska). The remaining time is spent ashore at the usually windswept, remote island breeding locations for courtship, nesting and chick rearing. Diomedea species are more commonly found on grassy slopes or plains where nests are often far apart, and rebuilt each nesting attempt, but located within sight of neighbors. The northern royal albatross uses the flat scrubby tops of small rocky islets, while Phoebetria species are usually widely spaced along steep grassy slopes and cliff ledges.

Behavior

Albatrosses cannot fly in calm weather, needing a good breeze to effect the soaring and tacking pattern of flight which enables large distances to be covered with little effort. Generally silent at sea, or in social resting or washing flocks. However, breeding colonies (especially close-nesting mollymawks) can be noisy with buzzing cries, clattering bills, and wailing screams accompanying a wide repertoire of body displays associated with recognition, threat, and courtship. While there are common components of display throughout the family, the dances and wing displays of the northern Pacific albatrosses have no equivalent in the Southern Hemisphere. The most intense courtship display sequences are seen among adolescent pre-breeders, often in small groups or gams. Some displays are between similar sexes within such groups. Birds that develop a pair-bond remove themselves from the group to a potential nesting site where the displays become shorter, gentler and more mutual without the flamboyance of courtship. Some (e.g. the sooty albatrosses) indulge in courtship flying interspersed with synchronous calling from both sexes both on the ground and in the air. Albatrosses generally defend small spaces associated with the nest site or territory. Fighting is not a regular occurrence, with a reliance on threat displays and charging, but the hooked bill can damage bills and eyes. Chicks at the nest site clapper their bills to discourage intruders (e.g. predatory skuas, Catharacta), followed by regurgitation of oily stomach contents if approached too closely. Considerable time is spent in self and mutual preening of plumage by adults, and of the growing chick by the parents.

Feeding ecology and diet

Various species of squid seem to provide the main component of the albatross diet. Many of these species are bioluminescent, and can be caught during the night. Some localised feeding spots provide a regular annual supply of carrion (e.g. during the annual die-off of Sepia cuttlefish on the eastern Australian coast) along established migration routes for some species. The diet also inlcudes a wide range of fish including small flying-fish, lampreys (Geotrea), pilchards (Sardinops) and crustaceans such as krills (Euphausia sp.), amphipods, copepods and crabs. Other recorded prey items include salps, seaweeds, barnacles, and fish spawn. Other small seabirds (prions, diving-petrels, and penguins) have been found in stomach contents as have examples of carrion from dead whales and seals. Some species can feed during the breeding season within a few hundred miles (kilometers) of the breeding place, as is the case with the northern royal albatross and the shy and Chatham mollymawks. Most food is gathered at the surface, but some of the smaller mollymawks may plunge and swim a short distance (up to 16 ft [5 m]) below the surface after prey. Kleptoparisitism has been recorded among waved albatrosses chasing boobies (Sula spp.), black-browed albatrosses from Phalacrocorax, and among eastern yellow-nosed albatrosses chasing shearwaters. Food is also obtained by some species from human fisheries offal, discards, and stolen baits.

Reproductive biology

Albatrosses usually build bowl-shaped nesting mounds with grasses and small shrubs bound together with soil, peat, or even penguin feathers where no vegetation is available. The waved albatross does not build nests, and the other northern Pacific albatrosses have very rudimentary ones that are rebuilt each season. Many Buller's mollymawks and black-footed albatrosses nest under trees in open forest. Most mollymawks nest in tight colonies just out of pecking range from neighbors, and reuse previous nest mounds.

Albatrosses are generally monogamous and most are annual breeders. Albatrosses lay one large white egg with reddish brown spots at the largest end weighing 7.0–18.2 oz (200–510 g) ranging from 5 to 10% of female body weight. First eggs are narrower and lighter. Incubation lasts 65–85 days with both sexes sharing the incubation stints, which may range from one day to as long as 29 days according to species foraging methods and locations. Hatching takes 2–5 days. Immediately after hatching, during the brooding (guard) stage of chick growth (15–40 days), one parent remains with the chick at the nest. Chicks fledge at 120–180 days for all small albatrosses, while Diomedea have a range of 220–303 days. Though breeding success can vary according to species and breeding season, fledging may be as high as 80% of eggs laid. Long-term averages can range from 25 to 67%, with the waved albatross being the lowest.

Recruitment of fledglings into the breeding population occurs at 5–15 years of age with 15–65% of those fledged surviving to breed. Biennial breeders take longer to become sexually mature. Annual mortality rates for adults range from 3 to 9%. The oldest known albatross was a northern royal albatross, still breeding at over 62 years old.

Conservation status

Albatrosses are long-lived, with delayed maturity and low reproductive output and adult mortality. This strategy ensures that only a small proportion of the population is breeding at any one time, with the remainder often in other parts of their range as adolescents or resting adult breeders. This mitigates the effects of localized disasters, but may disguise for some years any detrimental effects on populations or age groups which are more widespread. Threats which affect breeding birds have the most immediate impact, and recorded increases in adult mortality of 1–5% have significantly affected some colonies. Of the nearly 2 million breeding pairs of albatrosses worldwide in 24 recognizable taxa, 14 have populations of less than 20,000 breeding pairs. At the most populous level, the black-browed and the black-footed albatrosses have total populations that exceed 600,000 breeding pairs. However, some of these populations are fragmented, with a third of discrete groups having fewer than 100 breeding pairs. Most species have populations where there is not enough data to determine the rate of increase or decline, but have evidence of being exposed to known threats. The most vulnerable populations are those which are confined to one breeding locality. The high degree of philopatry of both juveniles and adults limits any ability to colonize new sites when facing adversity at their natal colony. Most factors adversely affecting populations involve human activities. However, climatic events have been seen to cause changes in habitat, which severely reduced breeding productivity in the northern royal albatross. Changing sea temperatures may also contribute to decline by changing food distribution and availability.

Significance to humans

The Rime of the Ancient Mariner, by S.T. Coleridge (1798), has done much to determine the popular conception of the albatross. The family name is derived from the name of the Greek hero of the Trojan War, Diomedes, whom the gods exiled to an isolated island, turning all of his deceased companions into large, white birds.

The preponderance of albatrosses breeding in locations remote from human habitation may indicate that closer populations were historically extirpated by humans. Certainly harvesting of eggs or chicks continues legally or illegally in a few locations today. During the past 250 years since the first naming of an albatross by Linnaeus, these legendary birds have been directly or indirectly exploited at sea and at their breeding colonies by those on boats—mariners, sealers, and whalers as food and artifacts, passengers as sport, and science as specimens.

Species accounts

Resources

BirdLife International. Threatened Birds of the World. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, 2000.

Croxall, J.P. ed. Seabirds: Feeding Ecology and Role in Marine Ecosystems. New York: Cambridge University Press, 1987. del Hoyo, J., A. Elliott, and J. Sargatal, eds. Ostrich to Ducks. Vol. 1 of Handbook of the Birds of the World. Barcelona: Lynx Edicions, 1992.

Marchant, S., Higgins, P.J., eds. Ratites to Ducks. Vol. 1A of Handbook of Australian, New Zealand and Antarctic Birds. Melbourne: Oxford University Press, 1990.

Robertson, G., R. Gales, eds. Albatross Biology and Conservation. Chipping Norton, Australia: Surrey Beatty, 1998.

Tickell, W.L.N. Albatrosses. Sussex: Pica Press, 2000.

Warham, J. The Petrels: Their Ecology and Breeding Systems. New York: Academic Press, 1990.

Warham, J. The Behaviour, Population Biology and Physiology of the Petrels. New York: Academic Press, 1996.

Cooper, J. ed. Albatross and Petrel Mortality from Longline Fishing International Workshop, Honolulu, Hawaii, USA. Report and presented papers. Marine Ornithology 28 (2000): 153–190.

Flint, E., K, Swift. eds. Second International Conference on the Biology and Conservation of Albatrosses and other Petrels, Honolulu, Hawaii, USA. Abstract of oral and poster presentations. Marine Ornithology 28 (2000): 125–152.

Nicholls, D.G., C. J. R. Robertson, P. A. Prince, M. D. Murray, K. J. Walker, G. P. Elliott. Foraging Niches of Three Diomedea Albatrosses. Marine Ecology Progress Series 231 (2002): 269–77.

BirdLife International. Wellbrook Court, Girton Road, Cambridge, Cambridgeshire CB3 0NA United Kingdom. Phone: +44 1 223 277 318. Fax: +44-1-223-277-200. E-mail: birdlife@birdlife.org.uk Web site:

[Article by: Christopher John Rutherford Robertson]