Vol 'f9i9 XVI ] MacCattghey, The Hawaiian Elepaio. 29 



extinct on Molokai and Maui. On the contrary, the evidence is 

 fairly conclusive that this form never inhabited the Molokai-Maui- 

 Lanai-Kahoolawe land-unit. The present islands composing this 

 unit are separated by channels less than 600 feet in depth, and 

 originally constituted a single continuous land-mass. Isolation 

 has taken place through subsidence. 



Two theories are tenable concerning the inter-island distribution 

 of Chasiempis. These theories also apply to many other Hawaiian 

 organisms. According to one theory the primitive ancestor, from 

 which Chasiempis evolved, landed upon the shores of one of the 

 three islands which it now inhabits, as a chance immigrant or 

 waif. 1 After a long period of time fortuitous inter-island migration 

 occurred, which resulted in the chance establishment of the bird 

 on Kauai, Oahu, and Hawaii, but in some unknown way missed 

 the Maui-Molokai group. Through isolation the forms on the 

 three islands developed as endemic species. 



The second theory derives the three present species from an 

 ancient stock which inhabited the primitive pan-Hawaii-land. 

 This land, many times larger and higher than the present island- 

 group, reached from northern Hawaii to and probably far beyond 

 Niihau, and has been lost through profound subsidence. The 

 present islands are the apices of subsided mountains. 2 The 

 primitive Elepaio ranged through pan-Hawaii-land and during 

 subsidence was isolated on the three islands already mentioned. 

 For some unknown cause it failed to continue on the Maui-Molokai 

 unit. 



The altitudinal range of Chasiempis on Kauai (5250 ft.) and 

 Oahu (4040 ft.) is approximately from 800 ft. to the highest sum- 

 mits. Originally, when the forests covered much more of the 

 lowlands than at present, and extended down to the strand in 

 many districts, the Elepaio was abundant at the lower levels. On 

 Hawaii (rising nearly to 14,000 ft.) the Elepaio ascends to the 

 upper limits of the forest zone (7,000-9,000 ft.) and descends in 

 certain places nearly to sea-level. It is most abundant between 



1 Just as a pair of Belted Kingfishers (Ceryle alcyon) landed and lived on the shores of 

 Hawaii, several years ago. 



- William Alanson Bryan, Deep Submergence of the Waianaes. Vaughan MacCaughey, 

 Outstanding biological features of the Hawaian Archipelago. 



