A Hutton, The Cormorants of New Zealand. | Is t "july 



dark birds took a fancy for each other ; why should their offspring 

 have the same partiality for dark breasts ? Why should they 

 not prefer white ones ? There seems to be nothing to make 

 the preferences take a particular direction ; and without this 

 the new variations would not become fixed. Perhaps dark birds 

 were driven away and were obliged to pair together. Or perhaps 

 some dark birds may have become physiologically isolated from 

 the rest. We want to know much more about the breeding 

 habits of the birds before we can form an opinion. 



There is still one other point. P. brevirostris, when young, 

 is entirely black, and the white chin and throat come afterwards. 

 Why, after commencing with the entirely black plumage of 

 P. pygmceus, should there be a partial advance in the white 

 throat ? I can offer no explanation of this ; but a white throat 

 is a feature found in the young of other species. 



The second group of New Zealand Cormorants (P . punctatus 

 and P. featherstoni) forms the sub-genus Sticticarbo, in which 

 the South American species, P. gaimardi, is also included. 



The third group forms the sub-genus Leucocarbo , and, in addition 

 to the New Zealand species, contains four from South America 

 and one from Kerguelen Island. The facts are too scanty to 

 enable us to say which way the second group has travelled. It 

 may, however, be possible to learn something about the migrations 

 of the second group. 



Our species of Leucocarbo may be divided into a carunculated 

 section, containing P. carunculatus , P. onslowi, and' P. traversi, 

 and a non-carunculated section, containing P. stewarti, P. cam p- 

 belli, P. colensoi, P. ran/urlyi, and P. chalconotus ; and, as the 

 skin on the lores is at first smooth and then becomes granulated, 

 I suppose that the carunculated section is descended from the 

 non-carunculated section. Again, many of the species are 

 characterized by having white bars on the wing-coverts and 

 lower back, which do not appear until the birds are mature. 

 Consequently we may assume that the species with these white 

 bars are descended from those without them. All the carun- 

 culated species, except P. verrucosus , from Kerguelen Island, 

 have white bars on the wings, and all but P. verrucosus and 

 P. traversi have white dorsal bars. This is confirmatory evidence 

 of the carunculated having descended from the non-carunculated 

 section. 



Of the non-carunculated species P. stewarti is the only one in 

 which both bars are present, and therefore it must be looked 

 upon as the connecting link between the sections. In P. colensoi 

 and P. campbelli there is an alar bar but no dorsal one, and the 

 alar bar is very narrow in P. campbelli . In the South American 

 species, P. bougainvillii and P. magellanicus , there is no alar 



