Vol. IV. 

 1 90s 



"1 HuTTON, Land Birds of New Zealand. 95 



Nyroca. Some of these may have 'crossed the Tasman Sea, 

 but it is more probable that the ancestors of most of them came 

 to New Zealand from New Caledonia. 



Thus we see that there is good reason for thinking that a 

 migration of land birds into New Zealand from the. north took 

 place in the Eocene period, for it is highly improbable that New 

 Zealand was ever again connected with the mainland. In the 

 Oligocene and Miocene periods New Zealand stood at a lower 

 level than at present by some 3,000 feet ; but in the older 

 Pliocene it had a much greater extent, and included the Chatham 

 and Auckland Islands, which were again separated from New 

 Zealand in the Newer Pliocene. 



Now, if we knew in detail the history of the origin of the land 

 birds of New Zealand it would enable us to solve several interesting 

 problems in the development of species. But as that is impossible 

 we must do the best we can with the imperfect knowledge we 

 have. 



In the first place we learn something about the relative ages 

 of certain groups ; for all those groups which are fairly well 

 represented in the fauna — such as the Psittaci, Rollidce, 

 Ardeidce, LimicolcB, AnafidcB, and Ratitce — must in all pro- 

 bability be old groups, unless they have crossed the Tasman Sea. 

 The Passeres are also fairly well represented, and, as they are 

 mostly forest birds and poor fliers, we may suppose that most 

 of them came to New Zealand in the Eocene period. But the 

 ColumbcB, the GallincB, and the Picarice are each represented 

 by a single species only ; and it is, therefore, presumable that 

 they have a later origin than the former. Among the Passeres 

 the absence of Oriolidce, La)iiid(S, Diccsidce, HirundinidcE, 

 PloceidcB, and others indicates that they are younger groups 

 than the Sturnidce, Meliphagidce, Muscicapidce, and Pittidce. 

 But this argument must be used with caution, because there 

 may be other reasons for the absence of a group of birds from 

 New Zealand than that it did not exist in the Eocene 

 period. 



Another subject of interest is the relative rate of change in 

 different species. When we look at things on a large scale we 

 find some regularity in this connection. For New Zealand (not 

 including the outlying islands) has 85 species, of which 58, or 68 

 per cent., are endemic. The Chatham Islands have 25 non- 

 migratory species, of which 10, or 40 per cent., are endemic ; 

 while the Auckland Islands have 14 species, of which 7, or 50 

 per cent., are endemic. So that New Zealand, which has been 

 separated longer from the mainland than the outlying islands 

 have been separated from New Zealand, has a larger per- 

 centage of endemic species. Also, neither the Chatham nor 

 the Auckland Islands have any peculiar families. The Auckland 

 Islands have one peculiar genus in Nesonetta ; and the Chatham 

 Islands have Cabalus and Nesoiimnas, and formerly Diophor- 

 apteryx and Palceolimnas, all belonging to the Rallidce. 



