Order PROCELLARIIFOBMES. 
No. 77. 
Family PROCELLARIIDM. 
HETEROPRION BELCHERI. 
THIN-BILLED PRION. 
(Plate 58.) 
Heteroprion belcheri Mathews, Birds Austr., Vol. II., pt. n., p. 224, July 31st, 1912 : Torquay 
Beach, Geelong, Victoria. (Bill figured ib., p. 215.) Mathews, Ibis, 1931 p. 571, 
July 17th. 
Adult. Like H. desolatus group in general coloration, but easily separated by its very thin bill, 
which is less than a third of its length. Wing 183 mm., culmen 25 mm. long and 8 wide at 
base, tarsus 33, tail 93. Figured. Collected thirteen miles due south of Geelong, Victoria, 
on the sea-beach on the 23rd of July, 1911, by Charles F. Belcher. 
Adult female. Similar to the adult male. 
Nest. An enlargement at the end of a burrow not far in, in soft ground. Or a natural hole under 
rocks, enlarged. 
Eggs. Clutch one, white, 43.5 to 51.5 mm. by 32-37. 
Breeding-season. November to December, on New Island, Falkland Islands. 
In the work quoted above I did not give a coloured figure of this species. 
Mr. A. G. Bennett is the first person to record the breeding of this species. 
He sends me the measurements of 57 clutches ; the average is 48 mm. by 35. 
The longest egg measured 51.5 and the shortest 43.5 ; the broadest 37 and the 
narrowest 32. The largest egg measured 50 by 37, and the smallest 45 by 32. 
These birds are known as Fire birds, because they fly to a fire or light. During 
the day they are out of sight, but at dark the air is full of them and then it is 
dangerous to walk about, as the birds fly into a person. 
Their burrows are so close together that a man walking over them sinks 
up to the knees, through past and present burrows, several one above the other. 
Vast numbers of these birds are eaten by the Skua. 
