NECTAR-FEEDING BIRDS OF HAWAII" 



The Drepanid Birds with Long Curved Beaks Developed Like the Lobelioideae — 



Curved Tubular Flowers 



DR. R. C. L. PERKINS in his 

 introductory remarks to section 

 Vertebrata of the "Fauna Hawai- 

 iensis" states: "Remarkable as are 

 some other members of the Hawaiian 

 Avifauna, yet it is upon the Drepanid 

 birds that the interest of the ornitho- 

 logist will always be centered. The 

 Drepanideae, include thirty-five species 

 belonging to no less than genera." It 

 may be remarked that the Drepanideae 

 are a family of birds peculiar to the 

 Hawaiian Islands and that, as Dr. 

 Perkins states, they are of unknown 

 origin, owing to their dubious relation- 

 ships with outside forms. "Dr. Gadow 

 has suggested, however, that they are 

 related to the Coerebidae, which fact, if 

 certain, would leave little doubt as to 

 their American origin." A large number 

 of the Drepanideae are nectar feeders 

 but Dr. Perkins also notes that nectar 

 is never the sole food, though a most 

 important source of nutriment, he 

 says: "Nectar is undoubtedly abso- 

 lutely necessary to the existence of 

 Himatione, Chlorodrepanis, Vestiaria, 

 Hemignanthus and Drepanis as they 

 are constituted; small moths, cater- 

 pillars, and spiders, their food — would 

 certainly fail them in sufificient quantity 

 at certain seasons." A number of the 

 Drepanideae have developed long 

 curved beaks "which make one wonder 

 for what purpose such an extraordinary 

 development can have taken place." 



"Practically all the plants visited by 

 birds for food had bell-shaped or tubu- 

 lar flowers in which the nectar was 

 more or less hard to reach ; most strik- 

 ing of all are the arborescent Lobelioi- 

 deae, and the multiplicity of these 

 peculiar plants and their isolation from 

 foreign forms bears a striking resemb- 

 lance to that of the Drepanid birds 

 themselves. 



Indicating likewise an extremely 

 ancient occupation of the islands, and 

 as the Drepanid birds are the pride of 

 the Hawaiian ornithologist, so are the 

 Lobelioideae of the Hawaiian botan- 

 ist." Perkins again says: "the devel- 

 opment of the extreme forms of these 

 birds is not comprehensible without a 

 knowledge of the island flora." 



"A series of observations made on 

 one of the most superb of the Lobeli- 

 oideae showed that it could only be 

 fertilized by these highly specialized 

 birds. In this species the pollen is 

 mature before the stigma is exserted, 

 by which time the pollen has vanished. 

 The latter cannot be wind-borne be- 

 cause it is shed in a viscid mass on 

 contact and so is constantly deposited 

 on the bird's forehead, from which it is 

 difficult to remove it." To this the 

 writer would remark that birds are 

 not essential to the pollination of 

 Hawaiian Lobelioideae though no doubt 

 they are important factors in pollina- 

 tion. In the Lobelioideae especially in 

 the Hawaiian species, we find at the 

 apex of the style immediately below 

 the stigmatic lobes and usually on the 

 lower surface of the stigmatic lobes, 

 rows of hair, which are on a level with 

 the base of the tube of the anthers at 

 the time of the pollen-discharge. The 

 pollen remains in the tube of the 

 anthers as the anthers are united and 

 thus the pollen cannot be disseminated. 

 At the time of the pollen discharge 

 within the tube, the style has usually 

 not reached its full length, but it con- 

 tinues to grow and as it pushed through 

 the anther-tube it brushes the pollen 

 with its rows of hair out of the tube, 

 and there the pollen remains adhering 

 to the bristles or bunches of hair, with 

 which usually the two lower, or in some 

 cases all five anthers are fitted out at 



' From "A Monographic Study of Hawaiian Speciss of the Tribe Lobelioideae, Family Cam- 

 panulaceae." J. F. Rock. Honolulu, 1919. 



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