Albatrosses (Diomedeidae)

The word Albatross is supposedly an English corruption of the Portuguese word 'alcatraz' meaning large seabird. In this way it describes Albatrosses expertly. Weighing up to 11.3 kg (25 lbs) and with wingspans of nearly 4 m (12 ft) Albatrosses are amongst the world's larger birds. Albatrosses can be distinguished from the other petrels because their tubular nostrils are placed at either side of the top mandible of their bill rather than being fused together on top.

There are at least 8 species of fossil Albatross which have been named. These fossils go as far back in time to about 60 MYA (million years ago). Fossil albatross have been found in England and USA and Japan, indicating that they once had a northern distribution which is believed to have ended 20 MYA when the Pacific and Atlantic Oceans ceased to meet in the Panama. The problem is the practically windless bit of ocean at the Equator called the doldrums which forms an effective barrier to birds which are dependent on wind to allow them to fly long distances. Surprisingly, none of the extinct Albatrosses were as large as the modern Wandering Albatross.

 

Occasionally a Back-crowned Albatross will discover a way across the doldrums and find itself trapped on the northern side of the Equator. One example was seen every year at a Gannetry in the Faroes (North Atlantic) from 1860-1894 while another has been seen regularly at Scotland's Bass Rock since 1967.

The 14 species of Albatross are often sub-divided into 3 groups:

Great Albatrosses : 3 species all with wingspans averaging around 3 m (10 ft) : Wandering Albatross, Royal Albatross and Amsterdam Albatross

Mollymawks : 9 smaller species with wingspans averaging 2.2 m (7 ft) : including Short-tailed Albatross, Laysan Albatross, Blackfooted Albatross, Waved Albatross, Black-browed Albatross.

Sooty Albatrosses : 2 species with wingspans averaging 1-2 m : Sooty Albatross and Light-mantled Sooty Albatross.

Table Of Albatrosses (Diomedeidae)
Wandering AlbatrossDiomedea exulans
Royal AlbatrossDiomedea epomophora
Amsterdam AlbatrossDiomedea amsterdamensis
Short-tailed AlbatrossPhoebastria albratus
Laysan AlbatrossPhoebastria immutabilis
Black-footed AlbatrossPhoebastria nigripes
Waved AlbatrossPhoebastria irrorata
Black-browed AlbatrossThallassarche melanophrys
Yellow-nosed AlbatrossThallassarche chlororhynchus
Grey-headed AlbatrossThallassarche chrysostoma
Shy AlbatrossThallassarche cauta
Buller's AlbatrossThallassarche bulleri
Sooty AlbatrossPhoebetria fusca
Light-mantled Sooty AlbatrossPhoebetria palpebrata

Of the 14 species of Albatross 3 live in the Northern hemisphere. Two of these species, the Laysan Albatross and the Black-footed Albatross are generally restricted to the Hawaiian Leeward Island chain. Though the Laysan Albatross will also breed on the Japanese Island of Torishima. Torishima is the only known breeding ground for the Short-tailed Albatross. This bird has had a very difficult last 100 years. Firstly, its populations were decimated by feather traders at the end of the 1800s. Then in 1939 and 1941 volcanic eruptions destroyed all the known birds and it was thought to be extinct. However, in 1953 it was found to be breeding there again, presumably, because juveniles of these long-lived birds had survived by being at sea during 1939 and 1941, only returning to the island on reaching maturity some years later when it was safe to nest again. It is now off the critical list but still listed as endangered.

The other 11 species of Albatross are all pretty much restricted to the southern hemisphere.

Albatrosses are large birds and as such have relatively small populations. Up to date estimates of world populations are hard to find, partly because of the highly dispersed nature of the population, but here are some estimates.


Wandering 36 000 breeding pairs about 90 000 birds altogether
Royal 16000 breeding pairs about 60 000 birds altogether
Wandering 100000 birds altogether
Laysan Albatross 2.5 million birds altogether
Black-footed 200 000 birds altogether
Waved Albatross 6000 birds altogether
Amsterdam Albatross 70 birds thought to be alive in 1994, 10 breeding pairs.
The Amsterdam Albatross is internationally accepted as a critically endangered species.

 

Ecology

Albatrosses feed primarily on squid though they also take fish. They mate for life, though partnerships will break up if breeding is unsuccessful for several years. The great albatrosses may not breed until they are 15/16 years old, though some will breed while younger. The smaller species take about 7 years to reach breeding maturity. Albatrosses breed in loose colonies on marine islands. The southern species build nests of soil and vegetation on the ground. The nests can be as much as 60 cm (24 in) high. There is a slight hollow in the middle where the single white egg is laid. Northern species lay on the bare earth or sand.

Both parents incubate the egg for about two days at a time. Incubation takes from 69-75 days - larger species taking longer than the smaller ones. For 3-4 weeks the altricial young are brooded by one parent or the other. After this time the parents are normally only present for the time it takes to feed the young. Fledging takes between 120 days (Black-browed Albatross) to 275 days (Wandering Albatross) This long fledging time means that the three larger species tend to breed only every second year.

Albatrosses are famous for their expressive courtship which involves dancing and in some species such as the Sooty Albatross, daring chases in flight with the following bird repeating every move of the leader. The dances vary between species however they are generally made up of actions used in other contexts but which appear to be adapted to the nuptial dance. These dances often have a set series of actions and reactions or responses by the courted partner. Quite a bit has been researched into deciphering the language of the Albatross behavioural mannerisms. I will describe just a couple of the 'actions' here, those who wish to know more should get hold of a copy of John Wareham's second volume on Petrels (see below).

'Skycall' - the bird stands with its wings open or not open and swings its head up giving a single loud bill clap on the way up. When the head is pointed upwards (at an angle of between 45 degrees and 90 degrees) it emits a loud series of notes with the head and bill held still.

'Leg action' - the bird lunges forward and claps its bill loudly then swings its head down to one side and rests it on or preens the feathers of the top of the leg.

'Bowing' - the bird standing lowers its neck and head towards its feet. It may take its head back between its legs. This action is often performed by pairs facing each other.

Causes of Death

As with most living creatures mortality is highest amongst eggs and young birds. Egg mortality is mostly the result of nest desertion which can be caused by poor weather, disturbance and failure of one partner to return from foraging on time. Human mediated changes in vegetation on the Forty-fours islets has resulted in Royal Albatrosses nesting directly on the rocky substrate. This has resulted in a large number of eggs getting cracked - up to 50%. Young chicks fall predator to skuas and gulls and when newly fledged may be taken by large fish when resting at sea. Most adult mortality occurs at sea and little is known about the causes. Oil slicks inevitably kill a selection of Procellariidae.

One of the more unusual causes of egg loss is attack by the Bristle-thighed Curlew, Numenius tahitiensis, which uses stones held in its bill to crack unattended Albatross eggs.






Book Reviews


The Behavior, Population Ecology and Physiology of the Petrels, by John Warham

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