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Albatross

2007 Schools Wikipedia Selection. Related subjects: Birds

                    iAlbatross
   Short-tailed Albatross (Phoebastria albatrus)
   Short-tailed Albatross (Phoebastria albatrus)
             Scientific classification

   Kingdom: Animalia
   Phylum:  Chordata
   Class:   Aves
   Order:   Procellariiformes
   Family:  Diomedeidae
            G.R. Gray, 1840

                                   Genera

   Diomedea
   Thalassarche
   Phoebastria
   Phoebetria

   Albatrosses, of the biological family Diomedeidae, are large seabirds
   allied to the procellariids, storm-petrels and diving-petrels in the
   order Procellariiformes (the tubenoses). They range widely in the
   Southern Ocean and the North Pacific. They are absent from the North
   Atlantic, although fossil remains show they once occurred there too.
   Albatrosses are amongst the largest of flying birds, and the great
   albatrosses ( genus Diomedea) have the largest wingspans of any extant
   birds. The albatrosses are usually regarded as falling into four
   genera, but there is disagreement over the number of species.

   Albatrosses are highly efficient in the air, using dynamic soaring and
   slope soaring to cover great distances with little exertion. They feed
   on squid, fish and krill by either scavenging, surface seizing or
   diving. Albatrosses are colonial, nesting for the most part on remote
   oceanic islands, often with several species nesting together. Pair
   bonds between males and females form over several years, with the use
   of ritualised dances, and will last for the life of the pair. A
   breeding season can take over a year from laying to fledging, with a
   single egg laid in each breeding attempt.

   Of the 21 species of albatrosses recognised by the IUCN, 19 are
   threatened with extinction. Numbers of albatrosses have declined in the
   past due to harvesting for feathers, but today the albatrosses are
   threatened by introduced species such as rats and feral cats that
   attack eggs, chicks and nesting adults; by pollution; by a serious
   decline in fish stocks in many regions largely due to overfishing; and
   by long-line fishing. Long-line fisheries pose the greatest threat, as
   feeding birds are attracted to the bait and become hooked on the lines
   and drown. Governments, conservation organisations and fishermen are
   all working towards reducing this by-catch.

Albatross biology

Taxonomy and evolution

   The albatrosses comprise between 13 and 24 species (the number of
   species is still a matter of some debate, 21 being the most commonly
   accepted number) in 4 genera. The four genera are the great albatrosses
   (Diomedea), the mollymawks (Thalassarche), the North Pacific
   albatrosses (Phoebastria), and the sooty albatrosses or sooties
   (Phoebetria). Of the four genera, the North Pacific albatrosses are
   considered to be a sister taxon to the great albatrosses, while the
   sooty albatrosses are considered closer to the mollymawks.

   The taxonomy of the albatross group has been a source of a great deal
   of debate. The Sibley-Ahlquist taxonomy places seabirds, birds of prey
   and many others in a greatly enlarged order Ciconiiformes, whereas the
   ornithological organisations in North America, Europe, South Africa,
   Australia and New Zealand retain the more traditional order
   Procellariiformes. The albatrosses can be separated from the other
   Procellariiformes both genetically and through morphological
   characteristics, size, their legs and the arrangement of their nasal
   tubes (see Morphology and flight).

   Within the family the assignment of genera has been debated for over a
   hundred years. Originally placed into a single genus, Diomedea, they
   were rearranged by Reichenbach into four different genera in 1852, then
   lumped back together and split apart again several times, acquiring 12
   different genus names in total (though never more than eight at one
   time) by 1965 (Diomedea, Phoebastria, Thalassarche, Phoebetria,
   Thalassageron, Diomedella, Nealbutrus, Rhothonia, Julietata,
   Galapagornis, Laysanornis, and Penthirenia).

   By 1965, in an attempt to bring some order back to the classification
   of albatrosses, they were lumped into two genera, Phoebetria (the sooty
   albatrosses which most closely seemed to resemble the procellarids and
   were at the time considered "primitive" ) and Diomedea (the rest).
   Though there was a case for the simplification of the family
   (particularly the nomenclature), the classification was based on the
   morphological analysis of Elliott Coues in 1866, and paid little
   attention to more recent studies and even ignored some of Coues's
   suggestions.
   Phylogenetic relationships of the 4 albatross genera. Based on Nunn et
   al 1996.
   Enlarge
   Phylogenetic relationships of the 4 albatross genera. Based on Nunn et
   al 1996.

   More recent research by Gary Nunn of the American Museum of Natural
   History (1996) and other researchers around the world studied the
   mitochondrial DNA of all 14 accepted species, finding that there were
   four, not two, monophyletic groups within the albatrosses. They
   proposed the resurrection of two of the old genus names, Phoebastria
   for the North Pacific albatrosses and Thalassarche for the mollymawks,
   with the great albatrosses retaining Diomedea and the sooty albatrosses
   staying in Phoebetria. Both the British Ornithologists' Union and the
   South African authorities split the albatrosses into four genera as
   Nunn suggested, and the change has been accepted by the majority of
   researchers.
   Black-browed Albatross, a mollymawk.
   Enlarge
   Black-browed Albatross, a mollymawk.

   While there is some agreement on the number of genera, there is less
   agreement on the number of species. Historically, up to 80 different
   taxa have been described by different researchers; most of these were
   incorrectly identified juvenile birds. Based on the work on albatross
   genera, Robertson and Nunn went on in 1998 to propose a revised
   taxonomy with 24 different species, compared to the 14 then accepted.
   This interim taxonomy elevated many established subspecies to full
   species, but was criticised for not using, in every case, peer reviewed
   information to justify the splits. Since then further studies have in
   some instances supported or disproved the splits; a 2004 paper
   analysing the mitochondrial DNA and microsatellites agreed with the
   conclusion that the Antipodean Albatross and the Tristan Albatross were
   distinct from the Wandering Albatross, per Robertson and Nunn, but
   found that the suggested Gibson's Albatross, Diomedea gibsoni, was not
   distinct from the Antipodean Albatross. For the most part, an interim
   taxonomy of 21 species is accepted by the IUCN and many other
   researchers, though by no means all — in 2004 Penhallurick and Wink
   called for the number of species to be reduced to 13 (including the
   lumping of the Amsterdam Albatross with the Wandering Albatross),
   although this paper was itself controversial . On all sides, there is
   the widespread agreement on the need for further research to clarify
   the issue.

   Sibley and Ahlquist's molecular study of the evolution of the bird
   families has put the radiation of the Procellariiformes in the
   Oligocene period (35–30 million years ago), though this group probably
   originated earlier, with a fossil sometimes attributed to the order, a
   seabird known as Tytthostonyx, being found in late Cretaceous rocks (70
   mya). The molecular evidence suggests that the storm-petrels were the
   first to diverge from the ancestral stock, and the albatrosses next,
   with the procellarids and diving petrels separating later. The earliest
   fossil albatrosses were found in Eocene to Oligocene rocks, although
   some of these are only tentatively assigned to the faimly and none
   appear to be particularly close to the living forms. They are Murunkus
   (Middle Eocene of Uzbekistan), Manu (early Oligocene of New Zealand),
   and an undescribed from from the Late Oligocene of South Carolina.
   Similar to the last was Plotornis, formerly often considered a petrel
   but now accepted as an albatross. It is from the Middle Miocene of
   France, a time when the split between the four modern genera was
   already underway as evidenced by Phoebastria californica and Diomedea
   milleri, both being mid-Miocene species from Sharktooth Hill,
   California. These show that the split between the great albatrosses and
   the North Pacific albatrosses occurred by 15 mya. Similar fossil finds
   in the southern hemisphere put the split between the sooties and
   mollymawks at 10 mya. The fossil record of the albatrosses in the
   northern hemisphere is more complete than that of the southern, and
   many fossil forms of albatross have been found in the North Atlantic,
   which today has no albatrosses. The remains of a colony of Short-tailed
   Albatrosses have been uncovered on the island of Bermuda, and the
   majority of fossil albatrosses from the North Atlantic have been of the
   genus Phoebastria (the North Pacific albatrosses); one, Phoebastria
   anglica, has been found in deposits in both North Carolina and England.
   See the genus accounts for more data on fossil species.

Morphology and flight

   Unlike most Procellariiformes, albatrosses, like this Black-footed
   Albatross, can walk well on land.
   Enlarge
   Unlike most Procellariiformes, albatrosses, like this Black-footed
   Albatross, can walk well on land.

   The albatrosses are a group of large to very large birds; they are the
   largest of the procellariiformes. The bill is large, strong and
   sharp-edged, the upper mandible terminating in a large hook. This bill
   is composed of several horny plates, and along the sides are the two
   "tubes", long nostrils that give the order its name. The tubes of all
   albatrosses are along the sides of the bill, unlike the rest of the
   Procellariiformes where the tubes run along the top of the bill. These
   tubes allow the albatrosses to have an acute sense of smell, an unusual
   ability for birds. Like other Procellariiformes they use this olfactory
   ability while foraging in order to locate potential food sources. The
   feet have no hind toe and the three anterior toes are completely
   webbed. The legs are strong for Procellariiformes, in fact, almost
   uniquely amongst the order in that they and the giant petrels are able
   to walk well on land.

   The adult plumage of most of the albatrosses is usually some variation
   of dark upper-wing and back, white undersides, often compared to that
   of a gull. Of these, the species range from the Southern Royal
   Albatross which is almost completely white except for the ends of the
   wings, to the Amsterdam Albatross which has an almost juvenile-like
   breeding plumage with a great deal of brown, particularly a strong
   brown band around the chest. Several species of mollymawks and North
   Pacific albatrosses have face markings like eye patches or have grey or
   yellow on the head and nape. Three albatross species, the Black-footed
   Albatross and the two sooty albatrosses, vary completely from the usual
   patterns and are almost entirely black (or dark grey in the case of the
   Light-mantled Sooty Albatross). Albatrosses take several years to get
   their full adult breeding plumage.

   The wingspans of the largest great albatrosses (genus Diomedea) are the
   largest of any bird, exceeding 340 cm (over 11 feet), although the
   other species' wingspans are considerably smaller. The wings are stiff
   and cambered, with thickened streamlined leading edges. Albatrosses
   travel huge distances with two techniques used by many long-winged
   seabirds, dynamic soaring and slope soaring. Dynamic soaring enables
   them to minimise the effort needed by gliding across wave fronts
   gaining energy from the vertical wind gradient. Slope soaring is more
   straightforward: the albatross turns to the wind, gaining height, from
   where it can then glide back down to the sea. Albatross have high glide
   ratios, around 1:22 to 1:23, meaning that for every metre they drop,
   they can travel forward 22 metres. They are aided in soaring by a
   shoulder-lock, a sheet of tendon that locks the wing when fully
   extended, allowing the wing to be kept up and out without any muscle
   expenditure, a morphological adaptation they share with the giant
   petrels.
   Taking off is one of the few times albatrosses use flapping in order to
   fly, and is the most energetically demanding part of a journey.
   Enlarge
   Taking off is one of the few times albatrosses use flapping in order to
   fly, and is the most energetically demanding part of a journey.

   Albatrosses combine these soaring techniques with the use of
   predictable weather systems; albatrosses in the southern hemisphere
   flying north from their colonies will take a clockwise route, and those
   flying south will fly counterclockwise. Albatrosses are so well adapted
   to this lifestyle that their heart rates while flying are close to
   their basal heart rate when resting. This efficiency is such that the
   most energetically demanding aspect of a foraging trip is not the
   distance covered, but the landings, take-offs and hunting they
   undertake having found a food source. This efficient long-distance
   travelling underlies the albatross's success as a long-distance
   forager, covering great distances and expending little energy looking
   for patchily distributed food sources. Their adaptation to gliding
   flight makes them dependent on wind and waves, however, as their long
   wings are ill-suited to powered flight and most species lack the
   muscles and energy to undertake sustained flapping flight. Albatrosses
   in calm seas are forced to rest on the ocean's surface until the wind
   picks up again. They also sleep while resting on the surface (and not
   while on the wing as is sometimes thought). The North Pacific
   albatrosses can use a flight style known as flap-gliding, where the
   bird progresses by bursts of flapping followed by gliding. When taking
   off, albatrosses need to take a run up to allow enough air to move
   under the wing to provide lift.

Distribution and range at sea

   The distribution of albatrosses across the world.
   Enlarge
   The distribution of albatrosses across the world.

   Most albatrosses range in the southern hemisphere from Antarctica to
   Australia, South Africa and South America. The exceptions to this are
   the four North Pacific albatrosses, of which three occur exclusively in
   the North Pacific, from Hawaii to Japan, California and Alaska; and
   one, the Waved Albatross, breeds in the Galapagos Islands and feeds off
   the coast of South America. The need for wind in order to glide is the
   reason albatrosses are for the most part confined to higher latitudes;
   being unsuited to sustained flapping flight makes crossing the doldrums
   extremely difficult. The exception, the Waved Albatross, is able to
   live in the equatorial waters around the Galapagos Islands because of
   the cool waters of the Humboldt Current and the resulting winds.
   Albatrosses range over huge areas of ocean and regularly circle the
   globe.
   Enlarge
   Albatrosses range over huge areas of ocean and regularly circle the
   globe.

   It is not known for certain why the albatrosses became extinct in the
   North Atlantic, although rising sea levels due to an interglacial
   warming period are thought to have submerged the site of a Short-tailed
   Albatross colony that has been excavated in Bermuda. Some southern
   species have occasionally turned up as vagrants in the North Atlantic
   and can become exiled, remaining there for decades. One of these
   exiles, a Black-browed Albatross, returned to gannet colonies in
   Scotland for many years in a lonely attempt to breed.

   The use of satellite tracking is teaching scientists a great deal about
   the way albatrosses forage across the ocean in order to find food. They
   undertake no annual migration, but disperse widely after breeding, in
   the case of southern hemisphere species, often undertaking circumpolar
   trips. There is also evidence that there is separation of the ranges of
   different species at sea. A comparison of the foraging niches of two
   related species that breed on Campbell Island, the Campbell Albatross
   and the Grey-headed Albatross, showed the Campbell Albatross primarily
   fed over the Campbell Plateau whereas the Grey-Headed Albatross fed in
   more pelagic, oceanic waters. Wandering Albatrosses also react strongly
   to bathymetry, feeding only in waters deeper than 1000 m (3281 feet);
   so rigidly did the satellite plots match this contour that one
   scientist remarked, "It almost appears as if the birds notice and obey
   a 'No Entry' sign where the water shallows to less than 1000 m". There
   is also evidence of different ranges for the two sexes of the same
   species; a study of Tristan Albatrosses breeding on Gough Island showed
   that males foraged to the west of Gough and females to the east.

Diet

   The albatross diet is dominated by cephalopods, fish and crustaceans,
   although they will also scavenge carrion and feed on other zooplankton.
   It should be noted that for most species, a comprehensive understanding
   of diet is only known for the breeding season, when the albatrosses
   regularly return to land and study is possible. The importance of each
   of these food sources varies from species to species, and even from
   population to population; some concentrate on squid alone, others take
   more krill or fish. Of the two albatross species found in Hawaii, one,
   the Black-footed Albatross, takes mostly fish while the Laysan feeds on
   squid.
   Light-mantled Sooty Albatrosses regularly dive in order to feed and can
   dive to below 12m.
   Enlarge
   Light-mantled Sooty Albatrosses regularly dive in order to feed and can
   dive to below 12m.

   The use of dataloggers at sea that record ingestion of water against
   time (providing a likely time of feeding) suggest that albatross
   predominantly feed during the day. Analysis of the squid beaks
   regurgitated by albatrosses has shown that many of the squid eaten are
   too large to have been caught alive, and include mid-water species
   likely to be beyond the reach of albatross, suggesting that, for some
   species (like the Wandering Albatross), scavenged squid may be an
   important part of the diet. The source of these dead squid is a matter
   of debate; some certainly comes from squid fisheries, but in nature it
   primarily comes from the die-off that occurs after squid spawning and
   the vomit of squid-eating whales ( sperm whales, pilot whales and
   Southern Bottlenose Whales). The diet of other species, like the
   Black-browed Albatross or the Grey-headed Albatross, is rich with
   smaller species of squid that tend to sink after death, and scavenging
   is not assumed to play a large role in their diet.

   Until recently it was thought that albatross were predominantly surface
   feeders, swimming at the surface and snapping up squid and fish pushed
   to the surface by currents, predators or death. The deployment of
   capillary depth recorders, which record the maximum dive depth
   undertaken by a bird (between attaching it to a bird and recovering it
   when it returns to land), has shown that while some species, like the
   Wandering Albatross, do not dive deeper than a metre, some species,
   like the Light-mantled Sooty Albatross, have a mean diving depth of
   almost 5 m and can dive as deep as 12.5 m. In addition to surface
   feeding and diving, they have now also been observed plunge diving from
   the air to snatch prey.

Breeding

   Wandering Albatrosses are colonial but have large widely spaced
   territories. Here a pair performs their famous breeding dance.
   Enlarge
   Wandering Albatrosses are colonial but have large widely spaced
   territories. Here a pair performs their famous breeding dance.

   Albatrosses are colonial, usually nesting on isolated islands; where
   colonies are on larger landmasses, they are found on exposed headlands
   with good approaches from the sea in several directions, like the
   colony on the Otago Peninsula in Dunedin, New Zealand. Colonies vary
   from the very dense aggregations favoured by the mollymawks (
   Black-browed Albatross colonies on the Falkland Islands have densities
   of 70 nests per 100 m²) to the much looser groups and widely spaced
   individual nests favoured by the sooty and great albatrosses. All
   albatross colonies are on islands that historically were free of land
   mammals. Albatrosses are highly philopatric, meaning they will usually
   return to their natal colony to breed. This tendency to return is so
   strong that a study of Laysan Albatross showed that the average
   distance between hatching site and the site where a bird established
   its own territory was 22 metres.

   Like most seabirds, albatrosses are K-selected with regard to their
   life history, meaning they live much longer than other birds, they
   delay breeding for longer, and invest more effort into fewer young.
   Albatrosses are very long lived; most species survive upwards of 50
   years, the oldest recorded being a Northern Royal Albatross that was
   ringed as an adult and survived for another 51 years, giving it an
   estimated age of 61. Given that most albatross ringing projects are
   considerably younger than that, it is thought likely that other species
   will prove to live that long and even longer.
   Sky-pointing is one of the stereotyped actions of Laysan Albatross
   breeding dances.
   Enlarge
   Sky-pointing is one of the stereotyped actions of Laysan Albatross
   breeding dances.

   Albatrosses reach sexual maturity slowly, after about five years, but
   even once they have reached maturity, they will not begin to breed for
   another couple of years (even up to 10 years for some species). Young
   non-breeders will attend a colony prior to beginning to breed, spending
   many years practicing the elaborate breeding rituals and "dances" that
   the family is famous for. Birds arriving back at the colony for the
   first time already have the stereotyped behaviours that compose
   albatross language, but can neither "read" that behaviour as exhibited
   by other birds nor respond appropriately. After a period of trial and
   error learning, the young birds learn the syntax and perfect the
   dances. This language is mastered more rapidly if the younger birds are
   around older birds.

   The repertoire of behaviour involves synchronised performances of
   various actions such as preening, pointing, calling, bill clacking,
   staring, and combinations of such behaviours (like the sky-call). When
   a bird first returns to the colony it will dance with many partners,
   but after a number of years the number of birds an individual will
   interact with drops, until one partner is chosen and a pair is formed.
   They then continue to perfect an individual language that will
   eventually be unique to that one pair. Having established a pair bond
   that will last for life, however, most of that dance will never be used
   ever again.

   Albatrosses are thought to undertake these elaborate and painstaking
   rituals to ensure that the correct partner has been chosen and to
   perfect recognition of their partner, as egg laying and chick rearing
   is a huge investment. Even species that can complete an egg-laying
   cycle in under a year seldom lay eggs in consecutive years. The great
   albatrosses (like the Wandering Albatross) take over a year to raise a
   chick from laying to fledging. Albatrosses lay a single egg in a
   breeding season; if the egg is lost to predators or accidentally
   broken, then no further breeding attempts are made that year. The
   "divorce" of a pair is a rare occurrence, usually only happening after
   several years of breeding failure.

   All the southern albatrosses create large nests for their egg, whereas
   the three species in the north Pacific make more rudimentary nests. The
   Waved Albatross, on the other hand, makes no nest and will even move
   its egg around the pair's territory, as much as 50 m, sometimes causing
   it to lose the egg. In all albatross species, both parents incubate the
   egg in stints that last between one day and three weeks. Incubation
   lasts around 70 to 80 days (longer for the larger albatrosses), the
   longest incubation period of any bird. It can be an energetically
   demanding process, with the adult losing as much as 83 g of body weight
   a day.
   Albatrosses brood young chicks until they are large enough to defend
   themselves and thermoregulate.
   Enlarge
   Albatrosses brood young chicks until they are large enough to defend
   themselves and thermoregulate.

   After hatching, the chick is brooded and guarded for three weeks until
   it is large enough to defend and thermoregulate itself. During this
   period the parents feed the chick small meals when they relieve each
   other from duty. After the brooding period is over, the chick is fed in
   regular intervals by both parents. The parents adopt alternative
   patterns of short and long foraging trips, providing meals that weigh
   around 12% of their body weight (around 600 g). The meals are composed
   of both fresh squid, fish and krill, as well as stomach oil, an
   energy-rich food that is lighter to carry than undigested prey items.
   This oil is created in a stomach organ known as a proventriculus from
   digested prey items by most tubenoses, and gives them their distinctive
   musty smell.

   Albatross chicks take a long time to fledge. In the case of the great
   albatrosses, it can take up to 280 days; even for the smaller
   albatrosses, it takes anywhere between 140 and 170 days. Like many
   seabirds, albatross chicks will gain enough weight to be heavier than
   their parents, and prior to fledging they use these reserves to build
   up body condition (particularly growing all their flight feathers),
   usually fledging at the same weight as their parents. Albatross chicks
   fledge on their own and receive no further help from their parents, who
   return to the nest after fledging, unaware their chick has left.
   Studies of juveniles dispersing at sea have suggested an innate
   migration behaviour, a genetically coded navigation route, which helps
   young birds when they are first out at sea.

Albatrosses and humans

Etymology

   The name albatross is derived from the Arabic al-câdous or al-ġaţţās (a
   pelican; literally, "the diver"), which travelled to English via the
   Portuguese form alcatraz (" gannet"), which is also the origin of the
   title of the former prison, Alcatraz. The OED notes that the word
   alcatraz was originally applied to the frigatebird; the modification to
   albatross was perhaps influenced by Latin albus, meaning "white", in
   contrast to frigatebirds which are black. The Portuguese word albatroz
   is of English origin.

   They were once commonly known as Goonie birds or Gooney birds,
   particularly those of the North Pacific. In the southern hemisphere,
   the name mollymawk is still well established in some areas, which is a
   corrupted form of malle-mugge, an old Dutch name for the Northern
   Fulmar. The name Diomedea, assigned to the albatrosses by Linnaeus,
   references the mythical metamorphosis of the companions of the Greek
   warrior Diomedes into birds.

Albatrosses and culture

   A Northern Royal Albatross in flight at the colony in Taiaroa Head, New
   Zealand.
   Enlarge
   A Northern Royal Albatross in flight at the colony in Taiaroa Head, New
   Zealand.

   Albatrosses have been described as "the most legendary of all birds".
   An albatross is a central emblem in The Rime of the Ancient Mariner by
   Samuel Taylor Coleridge; a captive albatross is also a metaphor for the
   poète maudit in a poem of Charles Baudelaire. It is from the former
   poem that the usage of albatross as a metaphor is derived; someone with
   a burden or obstacle is said to have 'an albatross around their neck',
   the punishment given in the poem to the mariner who killed the
   albatross. In part due to the poem, there is a widespread myth that
   sailors believe it disastrous to shoot or harm an albatross; in truth,
   however, sailors regularly killed and ate them, but they were often
   regarded as the souls of lost sailors. More recently, they have become
   part of popular culture, for example, in a Monty Python sketch, or the
   song " Echoes" by Pink Floyd. In the movie Serenity, the character
   River was referred to as an albatross by The Operative, reflecting the
   widespread adoption of the word as a metaphor. The Classic Crime's
   first album is entitled "Albatross".

   Albatrosses are popular birds for birdwatchers and their colonies
   popular destinations for ecotourists. Regular birdwatching trips are
   taken out of many costal towns and cities, like Monterey, Kaikoura,
   Wollongong and Sydney, to see pelagic seabirds, and albatrosses are
   easily attracted to these sightseeing boats by the deployment of fish
   oil into the sea. Visits to colonies can be very popular; the Northern
   Royal Albatross colony at Taiaroa Head in New Zealand attracts 40,000
   visitors a year, and more isolated colonies are regular attractions on
   cruises to sub-Antarctic islands.

Threats and conservation

   In spite of often being accorded legendary status, albatrosses have not
   escaped either indirect or direct pressure from humans. Early
   encounters with albatrosses by Polynesians and Aleut Indians resulted
   in hunting and in some cases extirpation from some islands (such as
   Easter Island). As Europeans began sailing the world, they too began to
   hunt albatross, "fishing" for them from boats to serve at the table or
   blasting them for sport. This sport reached its peak on emigration
   lines bound for Australia, and only died down when ships became too
   fast to fish from, and regulations stopped the discharge of weapons for
   safety reasons. In the 19th century, albatross colonies, particularly
   those in the North Pacific, were harvested for the feather trade,
   leading to the near extinction of the Short-tailed Albatross.
   This Black-browed Albatross has been hooked on a long-line.
   Enlarge
   This Black-browed Albatross has been hooked on a long-line.

   Of the 21 albatross species recognised by IUCN on their Red List, 19
   are threatened, and the other two are near threatened. Two species (as
   recognised by the IUCN) are considered critically endangered: the
   Amsterdam Albatross and the Chatham Albatross. One of the main threats
   is commercial long-line fishing, as the albatrosses and other seabirds
   which will readily feed on offal are attracted to the set bait become
   hooked on the lines and drown. An estimated 100,000 albatross per year
   are killed in this fashion. Unregulated pirate fisheries exacerbate the
   problem.

   Another threat to albatrosses is introduced species, such as rats or
   feral cats, which directly attack the albatross or its chicks and eggs.
   Albatrosses have evolved to breed on islands where land mammals are
   absent and have not evolved defences against them. Even species as
   small as mice can be detrimental; on Gough Island the chicks of Tristan
   Albatrosses are attacked and eaten alive by introduced house mice that
   are almost 300 times smaller than they are. Introduced species can have
   other indirect effects: cattle overgrazed essential cover on Amsterdam
   Island threatening the Amsterdam Albatross; on other islands introduced
   plants reduce potential nesting habitat.
   The remains of this Laysan Albatross chick show the plastic ingested
   prior to death, including a bottle cap and lighter.
   Enlarge
   The remains of this Laysan Albatross chick show the plastic ingested
   prior to death, including a bottle cap and lighter.

   Ingestion of plastic flotsam is another problem, one faced by many
   seabirds. The amount of plastic in the seas has increased dramatically
   since the first record in the 1960s, coming from waste discarded by
   ships, offshore dumping, litter on beaches and waste washed to sea by
   rivers. It is impossible to digest and takes up space in the stomach or
   gizzard that should be used for food, or can cause an obstruction that
   starves the bird directly. Studies of birds in the North Pacific have
   shown that ingestion of plastics results in declining body weight and
   body condition. This plastic is sometimes regurgitated and fed to
   chicks; a study of Laysan Albatross chicks on Midway Atoll showed large
   amounts of ingested plastic in naturally dead chicks compared to
   healthy chicks killed in accidents. While not the direct cause of
   death, this plastic causes physiological stress and causes the chick to
   feel full during feedings, reducing its food intake and the chances of
   survival.

   Scientists and conservationists (most importantly BirdLife
   International and their partners, who run the Save the Albatross
   campaign) are working with governments and fishermen to find solutions
   to the threats albatrosses face. Techniques such as setting long-line
   bait at night, dying the bait blue, setting the bait underwater,
   increasing the amount of weight on lines and using bird scarers can all
   reduce the seabird by-catch. For example, a collaborative study between
   scientists and fishermen in New Zealand successfully tested an
   underwater setting device for long-liners which set the lines below the
   reach of vulnerable albatross species. The use of some of these
   techniques in the Patagonian Toothfish fishery in the Falkland Islands
   is thought to have reduced the number of Black-browed Albatross taken
   by the fleet in the last 10 years. Conservationists have also worked on
   the field of island restoration, removing introduced species that
   threaten native wildlife, which protects albatrosses from introduced
   predators.

   One important step towards protecting albatrosses and other seabirds is
   the 2001 treaty the Agreement on the Conservation of Albatrosses and
   Petrels, which came into force in 2004 and has been ratified by eight
   countries, Australia, Ecuador, New Zealand, Spain, South Africa,
   France, Peru and the United Kingdom. The treaty requires these
   countries to take specific actions to reduce by-catch, pollution and to
   remove introduced species from nesting islands. The treaty has also
   been signed but not ratified by another three countries, Argentina,
   Brazil and Chile.

Species

   Current thinking divides the albatrosses into four genera. The number
   of species is a matter of some debate. The IUCN and BirdLife
   International among others recognise the interim taxonomy of 21 extant
   species, other authorities retain the more traditional 14 species, and
   one recent paper proposed a reduction to 13:
     * Great albatrosses (Diomedea)
          + Wandering Albatross D. exulans
          + Antipodean Albatross D. (exulans) antipodensis
          + Amsterdam Albatross D. (exulans) amsterdamensis
          + Tristan Albatross D. (exulans) dabbenena
          + Northern Royal Albatross D. (epomorpha) sanfordi
          + Southern Royal Albatross D. epomophora
     * North Pacific albatrosses (Phoebastria)
          + Waved Albatross P. irrorata
          + Short-tailed Albatross P. albatrus
          + Black-footed Albatross P. nigripes
          + Laysan Albatross P. immutabilis
     * Mollymawks (Thalassarche)
          + Black-browed Albatross T. melanophris
          + Campbell Albatross T. (melanophris) impavida
          + Shy Albatross T. cauta
          + Chatham Albatross T. (cauta) eremita
          + Salvin's Albatross T. (cauta) salvini
          + Grey-headed Albatross T. chrysostoma
          + Atlantic Yellow-nosed Albatross T. chlororhynchos
          + Indian Yellow-nosed Albatross T. (chlororhynchos) carteri
          + Buller's Albatross T. bulleri
     * Sooty albatrosses (Phoebetria)
          + Dark-mantled Sooty Albatross P. fusca
          + Light-mantled Sooty Albatross P. palpebrata.

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