406 
Synopsis of the Birds 
Pouncing from the sky on flying fishes, and never missing 
in the air ; unable to fish in water, from which they could 
not rise again ; skim the surface, or lie suspended with their 
wings raised over their back. Breed on trees on desert 
shores, or on elevated rocks : eggs one or two. 
Chiefly tropical. Formed of but two species, of which 
one is even doubtful. Analogous in form and habits to the 
Accipitres, especially the Eagles, which they replace on the 
sea.* 
f 
358. Tachypetes aquilus, Yieill. Purplish-black : orbits 
black ; shaft of the outer tail feather white beneath. 
Adult, summer plumage ? head white. 
Young, part of the breast and belly white. 
Frigate , Tachypetes aquilus , Nob. Am. Orn. v. Grande 
Fregate de Cayenne , Buff. pi. enl. 961. Pelecanus aquilus , 
leucocephalus, et palmerstoni , Gm . Lath . Tachypetes aquila , 
Vieill. Gal. des Ois. pi. 274. 
Inhabits the tropical seas, spreading somewhat in each 
temperate zone : not uncommon during summer on the 
coasts of the United States, as far north as South Carolina. 
The changes of plumage in this species, are not yet wel| 
known. 
79. SULA. 
Sula, Briss . Cuv. Temm. JRanz. Pelecanus , L . Gm. Lath. 
Dysporus , III. Morus, (since Sula) Vieill. 
Bill longer than the head, cleft beyond the eyes, robust, 
straight, conic-elongated, very stout at base, compressed, 
mandibles subequal ; upper seamed each side, ridge distinct, 
* This analogjr, observed by Linne, as is evident from his specific name, 
has lately been mistaken for affinity. 
