90 MANUAL OF PHILIPPINE BIRDS. 



'■^Coloration. — Similar to that of *?. fluviatHis [= hirundo], except that 

 the bill is always black and the feet are blackish. Adults are darker in 

 color, both above and below, but the difference is not great. All the meas- 

 urements appear identical, or nearly so, except those of the bill, which is 

 altogether smaller, and measures about 4'5 mm. from the gape." 

 {Blanford.) 



"Adult in winter. — Forehead flecked with white otherwise similar. 



"Immature. — Like that of fluviatilis [= hirundo'] from which it can 

 hardly be distinguished except by the color of the bill and feet and the 

 somewhat smaller size and more delicate shape of the latter.*' (Saunders.) 



80. STERNA BOREOTIS (Bangs). 



NORTHERN BERGIUS TERN. 



Sterna bergii Saunders, Cat. Birds Brit. Mus. (1896), 25, 89 (part); 



Shaepe, Hand-List (1899), 1, 136 (part). 

 Sterna bergii boreotis Bangs, Bull. Mus. Comp. Zool. ( 1901), 36, 2.50. 

 Sterna boreotis McGregor and Worcester, Hand-List (1906), 20. 



Ga-bi-o'-ta, general name for gulls and terns. 



Agutaya {McGregor) ; Balabac {Steere) ; Bantayan (McGregor) ; Bohol (Eve- 

 rett, McGregor) ; Calamianes (Bourns d Worcester) ; Caluya (Porter) ; Cebu 

 (Bourns d Worcester, McGregor) ; Cuyo (McGregor) ; Guimaras (Bourns & 

 Worcester) ; Leyte (Everett) ; Luzon (Bourns & Worcester) ; Masbate (Bourns 

 & Worcester) ; Mindanao (Murray, Koch d Schadenberg, Steere Exp., Bourns & 

 Worcester) ; Mindoro (Porter) ; Negros (Bourns t£- Worcester, Keay) ; Palawan 

 {Whitehead, Platen, Bourns d Worcester, White) ; Panay (Bourns d Worcester) ; 

 Pata (Mearns) ; Romblon (Bourns d Worcester, McGregor) ; Samar (Bourns d 

 Worcester) ; Sibuyan (Botirns d Worcester) ; Siquijor (Bourns d Worcester, 

 Celestino) ; Sulu (Bourns d Worcester) ; Tablas (Bourns d Worcester) ; Tawi 

 Tawi (Bourns d Worcester) . Liu Kiu Islands and Northern China Sea. 



"Adult male in full breeding plumage (type). — Forehead, cheeks, lores, 

 ear-coverts, neck all round, and whole under parts, including lining of 

 wing and bend of wing, pure white: crown and long occipital crest 

 glossy black; mantle, wings, rump, upper tail-coverts, and upper surface 

 of middle rectrices dark smoke-gray, darkest on wings and middle ot 

 back, where the color is almost mouse-gray; primary quills white; first 

 primary with outer web, a band along quill on inner web and tip blackish, 

 with a silvery suffusion which is most marked toward center of feather; 

 broad outer margin of inner web, below the black tip, white; second 

 primary similar but black tip deeper in color and extending a short 

 distance down outer margin of inner web, thus inclosing the white of 

 inner web for a short distance; third, fourth, and fifth primaries like 

 second, but black tip gradually growing deeper in color; outer rectrices 

 above pale smoke-gray at tips and along shafts, pale grayish white toward 

 base; second and third rectrices darker on the outer webs and at tip and 

 whitish toward base of inner webs. Bill in dried specimen, dull yellow 



