H-26 



RESEARCH PROGRAMMES 



have been the subject of long term study. Most species feed principally on zooplankton, 

 especially euphausiids, although a few concentrate their diets on fishes or squids. 



The breeding albatrosses (Diomedeidae) include six species, most of which occur largely in 

 the sub-Antarctic zone. Their natural history, fairly well known for some species, is 

 characterized by a lengthy period of immaturity during which individuals circumnavigate 

 the Antarctic perhaps more than once— one reason for their very low reproductive rates. 

 Albatrosses apparently feed heavily on pelagic squids and zooplankton. 



PLATE 5. Adelie Penguins. 



The petrels (Procellariidae, Hydrobatidae and Pelecanoididae) are a diverse group 

 represented by 24 species ranging in weight from 0.04 to 4.3 kg. With a few exceptions, they 

 are the least well known of Antarctic sea birds. The migrations and subsequent deaths elsewhere 

 of some species, for instance, the Sooty Shearwater Ptiffinns griseus, constitute a pathway by 

 which energy is transferred out of the Antarctic ecosystem. Dietary habits within the group are 

 diverse, the petrels' prey ranging from the tiniest zooplankton to the larger fishes, squids and 

 carrion. 



The shags (Phalacrocoracidae) are quite different from the penguins and petrels in that 

 they remain close to their breeding sites throughout the year and are confined in their feeding 

 to shelf areas around islands. Also their reproductive potential, as measured by the number of 

 eggs laid per breeding attempt, is much greater than that of the penguins and petrels. Their 

 breeding biology and ecology, however, are not well known. Because of their limited 

 distribution, they are important members of the Antarctic ecosystem only in small, local areas. 



The Stercoraciidae and Laridae, which include five species, are well known, particularly the 



