352 THE ANIMx\.LS OF NEW ZEALAND 



the starlings, the honey -suckers, the fiy-eatchers, and the pittas. 

 This argument, however, must l)e 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 regard things on a large scale, we find 

 some regularity in this connection. New Zealand, not including 

 the outlying islands, has 90 species, of which 58, or 68 per cent, 

 are endemic. The Chatham Islands have twenty-five 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. Therefore, New Zealand, which has been separated 

 longer from the main-land than the outlying islands have been 

 separated from New Zealand, has a larger percentage of endemic 

 species. It may be stated, also, that neither the Chatham Islands 

 nor the Auckland Islands have any peculiar families ; the Auck- 

 land Islands have, in the flightless duck, a peculiar genus, and 

 the Chatham Islands had formerly four peculiar genera of rails. 



But when we go into details, we come across many anomalies. 

 The tits have varied Ijetween the two islands, but the South Island 

 species is unaltered in the Chatham Islands and the Auckland 

 Islands. Sir Walter Duller explains this by supposing that the 

 birds in the Chatham Islands and the Auckland Islands are late 

 comers, having flown over from New Zealand; l)ut this explana- 

 tion seems to be improbable, for if the bird was capable of flying 

 to the Chatham Islands, it could certainly fly to the North Island, 

 which it has not done. The fern-bird has changed in the South 

 Island, where two species live together, but the tawny fern-bird 

 is the only species on the Snares, while the Chatham Islands fern- 

 bird is confined to those islands. The bell-bird has changed in the 

 Chatham Islands, but not in the Auckland Islands. On the other 

 hand, the tui has not changed on any of the islands. The North 

 Island wood-hen remains the only species in the north, but in the 

 South Island it has split up into three or four species. 



As might have been expected, no good fliers have representative 

 species in the two islands of New Zealand, but the bell-bird, the 

 ground-lark, the parrakeets, the wood pigeon, and the sand plover 



