336 NATURAL HISTORY OF HAWAII. 



finds forest conditions that are suitable to its habits over only a very limited 

 pcution of the mountain ;irea of the island. While it is an aetive. cm-ro-etic 

 bird, it has apparently never attempted to cross the channels to the iu';irby 

 island of Maui. For a hundred years at least it has been a rare bird (in iloln- 

 kai, so rare, indeed, that in 1907 the Avriter seeui'ed but three specimens as a 

 reward for seven weeks s|)fnt in the inountains in a search devoted to locating 

 this interesting- and curious si:)ecies. 



Still another interesing example of limited distribution among Hawaiian 

 bii'ds is that of the nene or Hawaiian goose, which is confined to the Island of 

 Hawaii, where it leads a life of seclusion, high up on the mountainside, seldom 

 if ever descending to the sea level. The Hawaiian duck is more widel.v dis- 

 tributed, having occurred in considerable numbers on all islands of the group. 

 Unfortunatel.v, since the introduction of the mongoose it has been (|uite rare 

 except on Kauai, where the mongoose has never been liberated. 



A Native H.\wk and OwIj. 



The Hawaiian hawk or io''' occurs only on Hawaii, where it is still fairly 

 connnon. The Hawaiian owP^ occurs on all tlie large islands. It is quite 

 closely I'elated to the short-eared owl, common on the American continent. 

 Since it differs from the American species onl.v in minor details, it is re- 

 garded as an island form of that species which has been reduced in size through 

 isolation. Like the coot and mud-hen, it is one of the more recent arrivals that 

 have made the islands their home long enough to allow the principles of evolu- 

 tion, especially those involved in isolation, to produce slight, though easily 

 recognizable, changes in the appearance of the species. Though the natural 

 history of the Hawaiian birds is of much general interest, it will be si'eii that 

 the sub.ject of the evolution of the various species presents material for con- 

 sideration that is of deeji and absorbing infei'est to all. 



The FAiiii>v DREPANnuD.E. 



The family IJrcpaiiididw, which includes the majorit\- oi the song birds 

 of Hawaii, is perhaps the most remarkable example of the evolution of a group 

 of birds to be found anywhere. The family which is peculiar to the islands, 

 includes about forty species that are found nowhere else in the wcn-ld. While 

 they are all much alike in their general structure, they differ amazingly in the 

 form of bill and also exhibit striking differences in the color of the plumage. 

 In almost all other families the form of the bill is quite uniform among the 

 species that belong to it. That organ usually bears a close connection with 

 the feeding habits of the group, and these are usually very nearly the same 

 for all the species in the family. I'.ut among the Drepanidulce of Hawaii we 

 find them fitted by their structure to almost every kind of life for which a 

 song bird in the tropics can become adapted. This adaptation of the bill has 



