Vol. XIX 

 igo2 



^] Ue:sshaw, T/ie Elepaio o/Nazvaii. 227 



as the bird breeds in its juvenile and transitional plumages, i.e., 

 before it is a year old, the young and the old more than once have 

 been described as different species. 



The writer is not aware that the habit of such precocious breed- 

 ing is paralleled among American birds of the temperate zone, but 

 it is common enough among Hawaiian birds and, probably, else- 

 where in the subtropics and the tropics. Not only do the juveniles 

 of the genus Chasiempis breed, mating with each other though per- 

 haps more often with older birds, but the same habit is observable, 

 though perhaps not so commonly, in the genera Psittirostra, 

 Heterorynchus and PhcBoriiis. In fact it is probable that all 

 Hawaiian birds begin to breed at a rather precocious age as com- 

 pared with their kind in the temperate zones. 



With the knowledge that the juvenile and adult states of Chasi- 

 empis were stages of but one species, and that the change of plum- 

 age was uniform in the three members of the genus — first eluci- 

 dated by Messrs. Palmer, Wilson and Perkins — the chief cause 

 of confusion in the group was eliminated. The sequence of 

 change from the juvenile through the transition stage to the final 

 adult plumage is now pretty well understood, though the length of 

 time necessary to the assumption of the final dress is not yet made 

 out. It also remains to consider the status of the bird found upon 

 the island of Hawaii, which is the main object of the present 



paper. 



The island of Hawaii is divisible roughly into two parts on the 

 basis of its rainfall, much of the windward side having a rainfall 

 of from over 100 to nearly 200 inches a year; while the fall on 

 most of the leeward side runs from 18 to less than 100 inches. 



With such marked differences of rainfall, accompanied by corre- 

 sponding differences of climate and vegetation, the ornithologist, 

 familiar with the results of climatic variation upon American birds, 

 will naturally expect to find similar variation among island species. 

 The effects of lesser rainfall and of climatic changes upon the 

 latter appear, however, to be much less noticeable than might be 

 expected from the above bare statement of the facts. 



Moreover they are probably somewhat less apparent to-day than 

 formerly, when the forest extended nearer, though in most parts 

 rarely perhaps, to the sea. For it is in the lowlands that the rain- 



