Northern (Pacific) Albatrosses

Genus Phoebastria

Four species:

  • Waved Albatross Phoebastria irrorata
  • Short-tailed Albatross Phoebastria albatrus
  • Black-footed Albatross Phoebastria nigripes
  • Laysan Albatross Phoebastria immutabilis

Evolution and taxonomy

Distribution

As the name of the groups says: all species occur are from the northern part of the Pacific Ocean. Only the Waved Albatross breeds on the Equator and disperses a in a restricted range a little into the Southern Hemisphere off Ecuador and Peru. The other three species are exclusively North-Pacific. They breed on several islands of the Hawaiian Chain (Laysan and Black-footed) and along the Tropic of Cancer from Mexico to the Bonin Islands (Laysan) and in the Japan area (Short-tailed and Black-footed). Non-breeding Laysan, Black-footed and Short-tailed disperse to the north and reach the Bering Strait.

Behaviour

The Phoebastria species are 'small' abatrosses (3-5 kg). What counts for the Great Albatrosses counts also for the smaller species: perfectly adapted to a gliding flight and dynamic soaring. Nevertheless they are better equipped for a flapping flight, which is expressed by the proportional weight of the flight musculature (ca 9%), smaller wing loading and lower aspect ratio (ca 13.8). Feeding is mainly done by surface picking and the walking and standing is relatively well developed.

Osteology



Waved Albatross Phoebastria irrorata. Location unknown
Culmen: ca. 150 mm (ramphotheca abraded), Total: 233.3 mm, unsexed adult. Courtesey of G. v.d. Brink 


Black-footed Albatross Phoebastria nigripes, California USA.
Culmen: 97.5 mm; total: 164.4 mm, adult female.
Courtesey of H. Nevins, Oikonos & J.A. v. Franeker, Imares, Netherlands

  • Skull
  • Flight apparatus
  • Pelvis and legs
  • Vertebrae and ribs

References