THE RAVEN 17 



villages, sometimes nesting on the church tower. Autres pays, autres 

 moeurs ! l 



The raven may, therefore, be termed " sub-gregarious," to use an 

 expression of Macgillivray. It does not, like the rook, form per- 

 manent societies, but more or less temporary unions, depending both 

 for their size and their duration upon widely varying local conditions. 



Though the gregariousness of the raven outside the breeding 

 season is of a fluctuating nature, the species appears to make a 

 regular habit of collecting to roost. In the Shetlands, Dr. Saxby saw 

 as many as eight hundred preparing to pass the night on the rocky 

 ledges of the tiny island of Uyea. We have also a very complete 

 account of a raven roost by a writer in the Field?- This was situated 

 on a ridge of rock two thousand feet up the side of a mountain, of 

 which the name is, for good reasons, withheld. The ground about the 

 ridge was strewn with pellets or castings, for the raven, like his 

 congeners and many other species, is in the habit of regurgitating 

 the indigestible portions of his food. The pellets in question were 

 found to consist chiefly of bone, wool, hair, mussel shells, crabs' toes, 

 corn husks, and a few feathers and bones of birds, eloquent testimony 

 to the bird's catholic tastes. 



In order to watch the arrival of the ravens, the narrator hid 

 himself one winter afternoon on the mountain side below the roosting 

 ledge. About four o'clock they began to appear, arriving first in 

 single pairs, then in small parties numbering up to eighteen, these 

 being in loose formation and more or less divided into pairs. Judging 

 from the scarcity of the species in the district, many of these arrivals 

 must have travelled distances exceeding twenty miles. They came 

 flying in at various altitudes, those at the higher levels descending a 

 hundred feet or more with swift dizzy rushes into the roost. During 



1 F. Diderich, Die geographische Verbreitung der echten Raben, 1889, pp. 68-81 ; Xauinann. 

 Vb'gel Mitteleuropas, iv. ; Baird, Brewer, and Ridgway, History of North American Birds, 1874, 

 vol. ii. ; Field, 1906, July-December, p. 1084 ;". Ibis, 1859, pp. 291-2, 312 (Tristram) ; H. L. Saxby, 

 Birds of Shetland ; Harvie-Brown and Buckley, Fauna of the Outer Hebrides, p. 73 ; E. Booth, 

 Notes on Birds, etc. 



2 Field, 1906, January-June, p. 689. 



C 



