BELL ROCK. 



xxxix: 



account of its geographical position ; but I am still in doubt whether Bell 

 Rock, from a faunal point of view, belongs really to Tay at all, or at least 

 in any appreciable degree. 



Geographically, Bell Rock belongs to Tay ; but, migrationally, Bell Rock, 

 to my sense of fitness, belongs to both Tay and Forth, but in a much less 

 degree to Tay than to Forth. 



Therefore, in support of my dubiety, I prefer to place this account of 

 Bell Rock in inferior type. 



A little further here on this question. If -we compare dates of the 

 arrivals of birds in the central portions of Scotland, and south of the 

 Firth of Forth, with those to the northward of the Tay, and if we grant 

 that the drift of migrants in greatest bulk is from the north-east, we find 

 that some species prevail in numbers to the south, and others prevail in 

 numbers to the north. Now, the contours of the Sidlaw and the Ochil 

 Hills serve on land as a splitting wedge to flights of some species ap- 

 parently, as I hope may appear under some of the species I have treated 

 of in the lists. It is quite a difficult problem to solve, but at present 

 I cannot apportion Bell Rock to Tay with any sense of satisfaction to 

 myself, if I take species for species as witnesses. Thus, some species 

 appear to aflFect the Tay route, i.e. pass the southern slopes of the Sidlaws 

 and north side of the Ochils, and others seem to prefer the Forth route, i.e. 

 by the south slopes of the Ochils and the wider Firth of Forth. In the 

 same way, greater numbers pass up the Firth of Forth than pass up the Tay. 

 The wider are the entrances to our land-routes, apparently the greater are 

 the numbers of individuals that take advantage of these wider routes. Thus, 

 in east England there are fewer land-routes to arrive at the know- 

 ledge of, and a much greater bulk of migrants comes to the eastern shores 

 of England south of the mountainous parts, and continues an un deviating 

 flight across that part of Britain, wherever the shores are low^-lying and the 

 low country continues far inland. 



Very shortly I desire to instance just a few species. The Whimbrels are 

 scarce across Tay. But though not uncommon at Tents Muir, which lies 

 between the entrances of the Firths of Tay and Forth, their further flight 

 seems to take them along the south slopes of the Ochils, and so on to: 

 the head of the Firth of Forth ; and they then di^dde against the eastern 

 spurs of the central hills of Stirlingshire, and the greater number follow^ 

 the south slopes and along the southern branches, of these hills in prefer- 

 ence to those of the northern slopes. 



The Great Grey' Shrikes are not uncommon at times from Girdleness south 

 along the coast and inland ; but to me their occurrences appear to be more 

 scattered there than further south along the Ochils on their south slopes 

 and through the central districts of Scotland. But here a larger accumu- 

 lation of records may prove necessary before this can be stated with accuracy. 



Wood-Pigeons of Continental origin at some seasons affect the Tay 

 route more than the Forth route, at least as regards the higher reaches, biit 

 enormous numbers arrive first upon our shores at the West Sands of St. Andrews; 



