2114 The Zoologist— Mav, 1870 



left, is an islet, spanned by a narrow bridge of rock, at its base ragged 

 pinnacles of rock, terribly black and still amid the churning white 

 foam. Cautiously descending, and crossing the " Devil's Bridge," 

 1 lay down behind a block of rock and look down. Close below, 

 looking so near that one could almost leap across, yet so far that the 

 strongest arm cannot throw a stone to reach it, is a stack of precipitous 

 rock, its sides and summit covered with birds : one can distinguish the 

 groups of rock birds ou the ledges, like black and white specks, the 

 ledges all white with excrement, but one cannot distinguish the 

 different species — only a confused mass of birds sitting in groups and 

 flying thick about the face of the rock. A pair of ravens, which have 

 been narrowly watching me, now draw near, and out from the cliff 

 beneath liop two juvenile ravens, and settle on the Devil's Bridge, 

 while I in vain try to stalk them. 



The climbers are below me, searching for eggs, but as the wind is 

 too strong I do not follow them, but take out my telescope and scan 

 the stack of rock and the grand precipices around me. Every crevice 

 and cranny of rock teems with countless thousands of rock birds, so 

 small, as seen from this great height, that the eye can only distinguish 

 the white patches and the long lines of birds dotting them : the air is 

 alive with birds, like clouds of gnats, flying about the cliffs, but the 

 distance is too great to observe accurately. This stack of rock rising 

 close in front is a breeding-place of the larger gulls, the great black- 

 back, the herring and the lesser blackback ; these, though they are for 

 ever haunting the precipices, watching for eggs left exposed by the 

 rock birds, seldom build in the midst of them, but generally on slacks 

 of rock near. As I watch I see several larger gulls restlessly floating 

 over the cliffs, and several pairs of herring gulls fly and float above 

 me, laughing and cackling; for go where you may, by night or day, in 

 the Outer Hebrides, if the herring gull sees you trying to stalk 

 anything, it is sure to come flying round just out of gun-shot, alarming 

 all the birds in the neighbourhood. The great blackback rises lightly 

 from its bulky nest, and with motionless wing is slowly lifted higher 

 and higher by the wind; now, altering the angle of its wings, swift as 

 an arrow, it floats before the wind, then curving gracefully round, 

 facing the wind, it is slowly borne aloft, advancing, to again float 

 everywhere backwards and forwards without one flap of its beauteous 

 wings. But while I am watching, what are those two gulls which 

 soar and float above the stack of rock — gulls the like of which 1 have 

 never seen before, the size of Larus canus, but with a black head ? 



