182 BIRDS OF TASMANIA. 



Nest. — A small burrow on the summit of small islets or a hole 

 in the face of a cliff on the sea-shore. 



Eggs. — Clutch one; roundish oval in shape; texture fairly fine; 

 surface without gloss and minutely pitted ; colour pure white. 

 Dimensions in mm. of four specimens in the British Museum 

 average 48 x 84. 



Breeding Season. — September. 



Oeographical Distribution. — Seas of Tasmania, Australia, New 

 Zealand, Southern Ocean down to at least 61 degrees south lat. ; 

 also South Pacific Ocean. 



Observations. — Prions, or "Whale-birds," are extremely diffi- 

 cult to separate into species, even when handled. 



" Of the genus Prion four species are recognized. They are 

 alike in plumage and markings. There is very little difference in 

 the dimensions except in the bill and in the development of the 

 lamellee at the base of the upper mandible, but with respect to 

 these characters great individual variation is displayed. Prion 

 vittatus has the largest bill, its sides being distinctly bowed and 

 graduating towards the tip. P. banski has a bill bowed on the 

 sides, but is smaller. I have, howevp.r, examined some specimens 

 which could not be referred with certainty to either P. vittatus or 

 P. banski, but were intermediate between the two. P. ariel and 

 P. desolatus have the sides of the bill straighter, but as in the 

 case of P. vittatus and P. banksi, it is not always possible to 

 separate the two species definitely " (F. Du Cane Godman). 



But little is known of the habits of the Broad-billed Prion, or, 

 for the matter of that, of any others of the genus. Usually con- 

 sorts in small parties, or even immense flocks. 



*BANKS DOV.E-PEION 

 {Prion banski, Gould). 



Male. — Head dark ashy-blue; back, rump, upper tail coverts, 

 and tail feathers ashy-blue; centre tail feathers broadly tipped 

 with black, outer ones with narrow white tips ; primary coverts and 

 primaries black; inner primaries and secondaries pearly-grey; sides 

 of the face and whole of under surface white; the bill has been 

 variously described as being " turquoisene lead colour," " blue and 

 slate colour," " bluish-grey " ; legs blackish. Dimensions in mm. ': 

 —Length, 255; bill, 27; wing, 200; tail, 90; tarsus, 30. 



Female. — Similar to male. 



Nest. — A burrow in the side of a hill. 



Eggs. — ''Clutch one ; roundish or broad oval in shape ; texture of 

 shell comparatively fine; surface without gloss; colour pure white. 

 Dimensions in inches :— (1) 2.01 x 1.38, (2) 2.0 x 1.4, (3) 1.98 x 1.49, 

 (4) 1.97 X 1.45, (5) 1.97 x 1.42, (6) 1.87 x 1.82 " (A. J. Campbell). 



