November 3, 1905.] 



'SCIENCE. 



555 



general structure, but diverging amazingly 

 from each other in the form of the bill, 

 with, also, striking differences in form of 

 body and in plumage. In almost all 

 other families of birds the form of bill 

 is very uniform within the group. It is 

 correlated with the feeding habits of the 

 bird, and these in all groups of wide range 

 become nearly uniform within the limits 

 of the family. With a great range of 

 competition, each type of bird is forced to 

 adapt itself to the special line of life for 

 which it is best fitted. But with many 

 diverging possibilities and no competition, 

 except among themselves, the conditions 

 are changed, and we find Drepanidge in 

 Hawaii fitted to almost every kind of life 

 for which a song bird in the tropics may 

 possibly become adapted. 



In spite of the large differences to be 

 noted, there can be little doubt, as Dr. 

 Hans Gadow, Mr. H. W. Henshaw and 

 others have shown, of the common origin 

 of the Drepanidse. A strong peculiar 

 goat-like odor exhaled in life by all of 

 them affords one piece of evidence point- 

 ing in this direction. There is, moreover, 

 not much doubt that the whole group is 

 descended from some stock belonging to 

 the family of honey-creepers, Coerebidse, 

 of the forest of Central America. Each 

 of the Hawaiian islands has its species of 

 Drepanine birds, some olive green in color, 

 some yellow, some black, some scarlet and 

 some variegated with black, white and 

 golden. The females in most cases, like the 

 young, are olive green. On each island, 

 most of the species are confined to a small 

 district, to a single kind of thicket or a 

 single species of tree, each species being 

 especially fitted to these localized surround- 

 ings. With the destruction of the forests 

 some of these species are already rare or 

 extinct. With high specialization of the 

 bill they lose their power of adaptation. 



In each of the several recognized genera 

 there are numerous species, mostly thus 

 specialized and localized, relatively few 

 species being widely distributed through- 

 out the islands. 



Most primitive of all, least specialized 

 and most like the honey creeper ancestry, 

 is the olive green Oreomystis hairdi of the 

 most ancient Island of Kauai. This bird 

 has a small straight bill, not unlike that of 

 the slender-billed sparrow. It is said to 

 be the most energetic and ubiquitous of 

 the group, feeding on insects on the trunlcs 

 of trees. If we assume that Oreomystis, or 

 some other of the genera with short and 

 slender bills, represents the original type 

 of Drepanidge, we have two lines of diver- 

 gence, both in directions of adaptation to 

 peculiar methods of feeding. 



Next to Oreomystis, on the one hand we 

 have Loxops and Himatione, with the bill 

 pointed, a little longer than in Oreomystis, 

 and slightly curved downwards. The 

 species, red or golden, of these two genera 

 are distributed over the islands, each on 

 its own mountain or in its own particular 

 forest. Vestiaria, another genus, remark- 

 able for its beautiful scarlet plumage, has 

 the bill very much longer and strongly 

 curved downward. Vestiaria coccinea, the 

 iiiwi of the islands, lives among the crimson 

 flowers of the ohia tree (Metrosideros) and 

 the giant lobelia, where it feeds chiefly on 

 honey, which is said to drop from its bill 

 when shot. According to Mr. S. B. Wilson, 

 the scarlet sickle-shaped flowers of a tall 

 climbing plant of Strongylodon lucidus 

 found in these forests 'mimic in a most 

 perfect manner both in color and shape 

 the bill of the iiiwi' so that the plant is 

 called nukuiiwi (bill of the iiiwi). 



The next genus, Drepanis, has the sickle 

 bill still further prolonged, forming a seg- 

 ment of a circle, and covering nearly 50 

 degrees. Drepanis pacifica, one of the 



