I 4 2 ANNALS OF SCOTTISH NATURAL HISTORY 



time, and if that egg is removed several will lay a third time, 

 in each case after an interval of fifteen or sixteen days. The 

 young bird, which is called " fathach," is fed in the nest till 

 it is fledged. It, like the young Fulmar, is also very fat and 

 is much relished as food. The old birds when fat, which 

 they often are, are also considered good eating. As they 

 never leave their holes by day, but always by night, it is 

 difficult to estimate their numbers, but I believe that they 

 are about as numerous as the Fulmar. When going away 

 from the nest, and when returning, it utters a peculiar cry, 

 and the same sound is frequently heard from the holes during 

 the day, and is the only sign that the birds are breeding in 

 your vicinity. When alighting on its return from the sea it 

 strikes the ground with considerable force, which seems to 

 stun it for a few seconds. It cannot alight easily on account 

 of the shape of its wings. These wings are fairly large and 

 powerful, so that it can fly and manoeuvre with great ease, 

 but at the same time they are of the diving pattern. A truly 

 aerial bird has wings which, when expanded, are nearly 

 straight from point to point and have great sustaining power ; 

 but a diving bird's wings are, when expanded, crescent-shaped 

 and have little sustaining power. As the wings of the Shear- 

 water are fairly large, but still of the diving pattern, they 

 appear less expanded and more crescent-shaped than those 

 of any other bird. Hence it is very frequently called 

 " cromag," or the crescent-shaped, and from this peculiarity 

 you can identify the bird a long way off. This shape of 

 wing, while not adapted for hovering, yet enables the bird to 

 fly very fast. As the wings are used most frequently for 

 flying under water, there no sustaining power is required- 

 only progress forward, and for this a diver's wings are 

 admirably adapted. I always heard the people say that the 

 divers progressed by flying under water, but I was unable 

 satisfactorily to verify the fact till last year (1840). It is 

 very seldom that the conditions are favourable for seeing 

 distantly what goes on under water, but on this occasion 

 everything was in my favour. I was standing on a high 

 projecting cliff where the bottom was white sand, the sun 

 was shining brightly, and the sea was smooth as glass and 

 wonderfully transparent. There were below me a large 



