Friday, May 11, 2007

Albatross Sea Birds



Waved Albatross



Albatrosses are large and heavy seabirds with very long and narrow wings and belong to the family of Diomedeidae in the order of Procellariiformes. They are related to the petrels, shearwaters and storm petrels, sharing tube-nosed bills with them. There are 14 species of albatrosses worldwide, found over all oceans but most species are concentrated in the southern hemisphere. In Ecuador one specie, the Waved Albatross, breeds exclusively on Galapagos in large colonies and is featured on this page. Other albatrosses are occasional seen in the Galapagos and along the Pacific coast as they are highly pelagic birds. One visitant which is recorded on the southwest Pacific coast is the Black-Browed Albatross.

All albatrosses possess a long and hooked bill which is composed of horny plates with a separate tubular and external nostril on both sides, which are used to secrete excess salt. Waved Albatross measure up to 86cm and can weigh up to 5kg with a wingspan of 2.40m. Their bodies are compact with short tails and legs and webbed feet.
Albatrosses are pelagic birds flying long distances over open waters without touching land for many days or even months. It is known that some Royal Albatrosses circle annually the entire globe over the southern oceans and our Waved Albatross ranges in the Pacific from Peru to Panama. Long and narrow wings giving them a high aspect ratio lets them to that. Wandering Albatrosses have a 3.7m wingspan, longest among all birds in the world. Their preferred food is squid but they also take fish and crustaceans snatching them from the water surface or just below it. They often feed sitting on the water making shallow dives rather than in flight. They are scavengers feeding on carcasses of dead whales and seals and are known to pick up any floating items including human garbage like plastics and so on.


12 000 pairs of Waved Albatrosses breed annually on EspaƱola island in the Galapagos from April to June (a few breed on Isla de la Plata) and stay there till December feeding their young till it is ready to leave the nest and take off by itself. Albatrosses are known for their elaborate courtship displays taking often 20 minutes perfoming bill clicking and circling bowing, swaying and whistling.
Waved Albatrosses are monogamous birds living together with its partner their whole life. The female lays one large egg (up to half kilo weight) directly on the ground with the male helping incubating the egg. After the chick hatches heavily downed and helpless both parents take care of it and feed it partly digested prey. The young stays then with its parents till it learns to fly and feed for itself which may take up another half year. As the circle is so long, many pairs only breed on alternate years and in case an egg breaks prematurely, no other attempt in producing one is made.

Being such large and heavy bodied birds and thus having a very heavy wing-loading, it is not easy for them to land and even more difficult to take off. One reason the waved albatrosses breed on EspaƱola is its relative flatness and higher cliffs. From their nearby breeding grounds they march in file to the edge of the cliff and spreading their wings drop off head first from there. After a short drop, the updraft of the air let it become airborne but once in the air but once in the air, they are graceful flyers, gliding on long and pointed wings with a high aspect ratio, which allows them to soar without need of frequent wingbeats and to travel great distances without exerting much energy.

Albatrosses are known to live long years (one record shows a 66 year old Royal Albatross) but some species are nevertheless in danger of extinction but luckily not Waved Albatross. The main cause is the fishing industry with many birds getting traped in fishing nets (it is calculated that around one million sea birds die that way each year). By also being scavengers many birds have high level of toxins in their body by consuming polluted items. In the past, at the beginning of the 20th century, many were also killed for their plumes to supply the growing textile industry.

Resources : Wikipedia, the free encyclopedia

No comments: