142 THE NATURAL HISTORY OF AILSA CRAIG. 



Aves. — Many species of birds find a home on Ailsa Craig, but 

 it is not proposed here to give an exhaustive list of those that are 

 resident or nest there, or such as have been recorded as occurring 

 as transient visitors only. It is still frequented by the peregrine 

 falcon (Falco peregrinus) and raven {Corvus corax), which continue 

 to breed, but the sea-eagle (ffaliaetus albicilla) has not been 

 known to nest there for many years. Not a few land birds, such 

 as the blackbird, wren, hedge-sparrow and wheatear, are pretty 

 common, and rock-pipits are very conspicuous, but its most 

 salient ornithological features are its colonies of rock-birds and 

 gulls which, though numbering among them but few species, occur 

 in the aggregate in tens of thousands. The herring-gull {Larus 

 argentatus) occurs in small numbers, being greatly exceeded by 

 the lesser black-backed gull {Larus fuscus). These two species 

 nest chiefly on the upper western slopes of the Craig, between the 

 cairn on its summit and the pillared crags. They form their 

 large nests of such plants as they find most readily at hand. The 

 nests are usually placed under the shelter of a block of rock 

 or the angles formed by two of the sides of neighbouring pillars, 

 like an open book, and are unprotected towards the sea. They 

 begin laying about the middle of May. These gulls are omnivorous 

 feeders, and are credited with doing considerable harm to the 

 rock-loving species. The kittiwake gull {Rissa tridactyla) unlike 

 the two preceding species is strictly a maritime bird, and its nest 

 is placed in the ledges of the precipices overlooking the sea. 

 Thousands of kittiwakes nest on the Craig. If, after landing at 

 the jetty, the visitor passes to the right hand, he will shortly find 

 himself under tremendous precipices, at this point chiefly tenanted 

 at the bottom by the beautiful kittiwakes. The cliffs are occupied 

 from about fifteen feet from the ground, and thence upwards, 

 reaching the summit at some parts, every little jutting piece of 

 rock has its nest, and every rocky platform several. Only a few 

 inches for the groundwork of a nest are necessary to ensure the 

 occupation of a ledge. Nearly all the nests I have seen have 

 been composed of the bladder and red campions. On these 

 nests, their pure white and pearly-grey forms beautifully relieved 

 against the grey rocks, sit the kittiwakes, comparatively heedless 

 of intrusion. A too near approach will send them off with a 

 querulous repetition of their trivial name — kittiwake, kittiwake ! 



