AVIFAUNA OF LAYSAN. 



23 



Fregetta aquila?, Ramsay, Proc. Linn. Soc. N. S. W. i. p. 375 (187G) (Solomon Is.). 

 Fregata strumosa, Kittl. MS. teste Hartert, Katal. Mus. Seuekcnb. p. 233 (1891). 



Adult male from Laysan, Above black witli metallic gloss, the lanceolate feathers of the 

 back and scapulars strongly glossed with green and purple j median wing-coverts brown 

 with blackish centres ; wings and tail black ; under surface deep blackish brown without 

 gloss. Total length about 41 inches, wing 23, tail 15*8, bill i' 1. 



Female from Laysan, Feathers of the back and scapulars not lanceolate. Above deep blackish 

 brown with very little gloss, much paler on the lower hind neck ; median wing-coverts 

 pale brown with dark brown centres ; throat and sides of neck dull whitish brown ; 

 breast and sides down to the Hanks white. Wings 238 to 21 inches, tail 1G, bill 4'7. 



Immature birds from Laysan. The head white ; beneath the throat rufous cinnamon ; breast 

 brown ; abdomen white ; under tail-coverts black. Another specimen has the neck and 

 head cinnamon-rufous, and the whole under surface white. 



In appearance and measurements my specimens agree with Frigate-birds from other 

 localities (Pacific Ocean and Madagascar, whence only the quite distinct Fregata minor 

 (Gm.) has hitherto been recorded), but two adult males from the West-Indian seas (one 

 south of Florida and one from Aruba) have the lower surface deeper black, and no sign 

 of the pale upper wing-coverts. 



The cinnamon-rufous tinge of the usually white head and neck of immature birds is 

 very strongly developed in my specimens from Laysan, but a specimen of Fregata minor 

 (Gm.) from Borneo shows it equally well, and the same has been recorded of specimens 

 from other countries. 



The nestling is covered with very soft and fluffy white down. 



Kittlitz (see Mus. Senckenb. i. p. 121, and Kupfertafeln, pi. 20 and text p. 15) believed 

 the young bird with the white head to belong to a different species, which, however, is 

 not the case. 



The eggs from Laysan measure 2'8 by 1SG and 2"(j5 by 1'9 inches, and are dull white in 

 colour. The shell is covered with a chalky crust like those of the Gannets, Pelicans, 

 Cormorants (but thinner than in most of the latter), clearly indicating their belonging to 

 the Steganopodes. 



There are numerous rookeries of the Frigate-birds on Laysan and most of the other islands 

 visited, almost wherever there is scrub. Their breeding-season is from the middle of 

 May to the middle of July. Their nests are made of twigs and used year after year, till they 

 become often mere masses of guano and dead birds. These nests are built on the top of the 

 bushes, and from half a dozen to fifty are found in one rookery. The male is as much on 

 the nest as the female. They lay only one egg. They live principally on fish, hut often 

 eat the disgorged food and young of other birds. 



