Quantcast
Last updated on April 18, 2014 at 8:42 EDT

Atlantic Yellow-nosed Albatross, Thalassarche chlororhynchos

The Atlantic Yellow-nosed Albatross is a member of the albatross family. It is a large sea bird sometimes called a “mollymawk”. It was once thought to be conspecific with the Indian Yellow-nosed Albatross and known as the Yellow-nosed Albatross. Some of the authorities still believe that species are the same, such as Jeff Clements and the SACC, which sees that a proposal is needed.

A mollymawk is a type of albatross that belong to the Diomedeidae family and come from the Procellariiformes order, along with Shearwaters, Fulmars, Storm Petrels, and Diving Petrels. They share certain physical features. Firstly, they have nasal passages that attach to the upper bill called naricorns, although the nostrils on the albatross are located on the side of their bill. The Procellariiformes’ bills are also special in that they are split into between 7 and 9 horny plates. Finally, they formulate a stomach oil made of wax esters and triglycerides that is held in the proventriculus. This is utilized against predators as well as a food source that is rich in energy for chicks and for the adults during their long flights. The birds also contain a salt gland that sits above the nasal passage and helps desalinate their bodies, because of the high amount of ocean water that they take in. It leaks out a high saline solution from their nose.

The Atlantic Yellow-nosed Albatross is about 32 inches in length. It’s typically black and white with a grey head and large eye-patch, and its nape and hind neck are white. It has a black bill with a yellow culmenicorn and a pink tip. It has a blackish grey saddle, upper wing and tail, and its underparts are mostly white. Its primaries and its underwing show a narrow black margin. The immature birds are similar to the adult birds but with a white head and a black bill. It can be differentiated from the Indian Yellow-nosed because of its darker head. Compared to other mollymawks it can be distinguished by its smaller size and the thin black edging to the underwing. The Grey-Headed Albatross has a similar grey head but more pronounced and less well defined black markings around the edge of the underwing. Salvin’s Albatross also has a grey head but has much broader wings, a pale bill and even skinnier black borders to the underwing.

The primary diet of the Yellow-nosed Albatross is squid, fish, and crustaceans.

Just like all other albatross, they are colonial, but unusually they will build their nests in scrub or amongst Blechnum tree ferns. Just like all other mollymawks, they build pedestal nests of mud, peat, feathers and vegetation to lay their one egg in. They usually do this in September or early October, and the chick usually fledges in late March to April. The Yellow-nosed Albatross breeds annually.

These birds nest on islands in the mid-Atlantic, including Tristan da Cunha and Gough Island. At sea, they can extend across the south Atlantic from South America to Africa.

The IUCN categorized this species as Endangered with an occurrence range of 6,500,000 sq mi and a breeding range of 31 sq mi. A 2001 population assessment breaks down the population and shows some trends. Gough Island has 5,300 breeding pairs, between 16,000 and 30,000 breeding pairs on Tristan da Cunha Island, 4,500 on Nightingale Island, between 100 and 200 pairs on Middle Island, and 500 pairs on Stoltenhoff Island, and 1,100 on Inaccessible Island. This tallies up to between 27,500 and 41,600 pairs per year for the total between 55,000 and 83,200 total mature birds. This population estimate was completed in 1983, however and is outdated. Patterns suggest a 50% decrease over 72 years. Their largest threat is from long-line fishing, as harvesting of chicks and adults have been outlawed.

Planning for helping conserve this species is underway, with counting of the birds on Gough Island. Also, Gough Island and Inaccessible Island are nature preserves, and Gough Island is a World-Heritage Site. The Tristan da Cunha population is being tenuously tracked and counted and the Southeast Atlantic Fisheries Commission has passed a motion that all the fishing vessels use a tori line and drop lines at night.

Image Caption: Gough Island. The Atlantic yellow-nosed albatross (Thalassarche chlororhynchos), which breeds on the island, is classified as endangered (EN A4bd) on the World Conservation Union Natural Resources Red List 2004. Although originally endangered as a result of longline fishing, albatross chicks are now under threat from a mouse (Mus musculus) introduced to the island. Credit: Steven Chown/Wikipedia  (CC BY 2.5)

Atlantic Yellow-nosed Albatross Thalassarche chlororhynchos