ISO ANNALS OF SCOTTISH NATURAL HISTORY 



This is quite a different movement from the other just described, 

 and, so far as I can see, has never had any influence upon the 

 settlement of the species as a resident. The same movement still 

 continues with little change i.e. Rooks in considerable numbers 

 still visit the Outer Hebrides, but remain a short time, when a big 

 fall of snow has fallen on the mainland. Mr. A. M'Elfrish reports 

 such flocks "about every other year both in North Uist and Ben- 

 becula." But it may be perfectly likely that these sporadical 

 emigrations (from the " force of circumstances ") may have, in course 

 of time, initiated the greater, until the habit extended, and a great 

 new " line of advance and retreat " has at last been inaugurated. I 

 cannot help looking upon such records as the above as new develop- 

 ments of great interest from the points of view which must be taken 

 of the past and present dispersal of species, and the intimate 

 relationships which exist between migrational and distributional 

 phenomena and the dispersal of animal life. 



RAVEN (Corvus corax), p. 71. No diminution appears to have 

 taken place in the numbers of the bird, though, as Mr. Radclyffe 

 Waters tells me, determined raids are made upon them every spring 

 by the keepers, for they " undoubtedly visit us in large numbers 

 from the mainland," and, " they were very destructive in the nesting 

 season of 1893. On arriving at Galston in September 1894, I 

 found that the keeper had a row of about twenty recently killed, 

 laid out for my inspection." I am myself inclined to attribute this 

 annual immigration to the large numbers which it is well known 

 are to be found in Shetland, and to an emigration of the surplusage 

 from there, though I am quite willing to credit also a much more 

 extensive movement from farther east. 



Other accounts bear out the above. Mr. M'Elfrish tells me, 

 for instance, that while a few breed on North Uist, a dead sheep 

 will attract numbers of them. Mr. M'Elfrish has seen as many 

 as twenty-six round one dead sheep. 



SWIFT (Cypsehis apus), p. 73. The occurrences of the Swift in 

 the Outer Hebrides being far from common, I consider that records 

 should be kept. The scarcity of records appears to point to an 

 absence of suitable nesting-places, though I do not think that 

 this is the true factor to account for their "visible scarcity." Swifts 

 as often migrate by day, I fancy, as by night. Dr. M'Rury says 

 he does not remember seeing any Swifts in these islands before 

 June 29, August 18, and August 27, 1891. ("Ann. Scot. Nat. 

 Hist." 1892, p. 199 but compare "Fauna of the Outer Hebrides," 

 p. 73). Later, Dr. M'Rury reports that one or two are usually 

 observed every summer on passage by him. Also one at Flannan 

 Isles, June n, 1900 ("Ann. Scot. Nat. Hist." 1901, p. 135). 



NIGHT JAR (Caprimulgus eitropiztts), p. 74. This is an addition 

 to the Fauna of the Outer Hebrides, and is reported from the light- 



