BIKD EOCK 177 



variability in marking wliicli suggests that the 

 white stripe of the Ringed Murre is a similar indi- 

 vidual peculiarity. 



Next to the Murres the Kittiwakes are probably 

 the most numerous birds on the Rock. Doubtless 

 for the reason that they select the less accessible 

 ledges where their eggs can not be so readily taken, 

 their young were more advanced than those of any 

 other of the birds breeding here. Their nests, rather 

 bulky structures of seaweed, which often projected 

 well over the edge of the ledge on which they were 

 built, contained only young with their parents, one 

 or two birds constituting a brood."' 



Kittiwakes were never observed perching on the 

 upper ledges or rim of the Rock in the situations 

 commonly selected by Murres, Razorbills, and Puf- 

 iins. The last-named species, in fact, was never seen 



... .:'A 



'iHt 



\t-i. Kutraiiee to Full 



resting far from the top of the Rock, and its nests 



were placed in burrows excavated on the summit of 



the Rock, at the west end. Occasionally advantage 

 13 



