242 
BRITISH BIRDS. 
recefles of the rocks, where they and their mates, 
while employed in rearing their young, are heard 
in croaking, clucking converfe, not unlike the un- 
varied hollow founds of a number of frogs. They 
are accounted a ftupid race of birds, becaufe they 
feem fearlefs of danger, and fuffer themfelves to be 
fo nearly approached as eafdy to be Ihot, or even 
knocked on the head. In the prefervation of their 
young they feem to have only one mode of defence, 
and that is the fmgular faculty of fquirting oil from 
their bills, with great force, on the face of their 
enemy ; by which means they fometimes fucceed in 
difconcerting his attempts to rob their nefts. They 
are a remarkably oily fat race of birds. 
Ornithologifts have reckoned nineteen fpecies, 
and a few varieties, of the Petrel, whofe noftrils 
are contained in a fingle tube, — and four fpecies 
which have noftrils divided into two tubes. Three 
fpecies only of this genus are accounted Britifli 
j^irds. 
