-62- 



rookery location) . Mature cows join them in about three 

 weeks to form harems of up to 30 cows per bull. Within a 

 week, the cows give birth to a single pup and then become 

 sexually receptive two to three weeks later. Following 

 copulation on land, the harems break up and the bulls return 

 to the ocean for a short interval before reforming groups 

 on land to molt. 



Most female elephant seals become mature at one to 

 three years. Males, apparently mature at four years, remain 

 reproductively inactive until six (Laws, 1956a) . 



4) Food Habits 



Although much is known about certain features of elephant 

 seal natural history, its feeding habits are not well known. 

 When on land, where most studies have been done, they in- 

 variably fast (Laws, 1977a), making determination of foods 

 taken impossible. It does seem, however, that the majority 

 of their food consists of fish and cephalopods (Table 9) . 

 Young seals may feed on amphipods for a short time after 

 weaning (Laws, 1956a). 



D. Antarctic Birds 



Birds play a critical role in the Antarctic marine 

 environment. This section relates standing stock and biomass 

 estimates to feeding in order to assess the ecological 

 significance of Antarctic avian populations. Thirty-eight 

 seabird species with breeding and/or feeding ranges extend- 

 ing south of the Convergence are considered (some move into 

 Antarctic waters after breeding on islands like Marion and 

 Prince Edward, the Crozets, Kerguelen, and Macquarie) . 

 Antarctic and subantarctic faunal zones have been delineated 

 (review in Watson et al., 1971) along a track which roughly 

 follows the northern limits of the pack ice. Related species 

 are grouped and discussed in terms of their overall position 

 within the Antarctic region. 



1. Penguins 



a. Distribution 



The circumpolar distributions of the seven penguin 

 species breeding in the Antarctic are shown in Figure 19 . 

 Of the two large Aptenodytes species, emperor penguins breed 

 on continental fast ice (Voous, 1965) and king penguins 

 breed on islands north of the pack ice zone (Conroy and 

 White, 1973) . The three Pygoscelis species show a graded 

 series of ranges from north to south. Adelie penguins occur 



