FAUNAL AREA AND ITS POSITION. 



Ixxiii 



to think that it has more influence in favour of Forth than of Tay. 

 I have already referred to this in a previous page. 



The interior or bulging portion of the pear-shaped area as 

 described, forms with its high elevations a cul-de-sac of much more 

 topographical importance. Thus, except where the low levels run 

 between Strathmore and the drainage of the river Tay, and again 

 where the lower reaches of Tay lead by insignificant and slightly 

 defined watersheds to the Vales of Allen and Menteith in Forth and 

 to the Clyde area, it forms a definite barrier between Tay and Dee 

 and the other areas to the north and west. Also, eastward of the 

 Lomond Hills, there is little to divert the flow to Forth over the 

 open and wide Howe of Fife. 



As for the more isolated ranges of comparatively low elevations 

 presented by the Sidlaw Hills in Forfar and the Ochil Hills in Fife, 

 these offer some slight resistance as a wedge, just as the central hills 

 of Stirlingshire tend to split up the migratory birdflights which pass 

 on towards Clyde. 



To what extent these interruptions may influence migration- 

 flights may not yet be perfectly clear, and we may well await the 

 further developments which no doubt will appear when Forth 

 comes to be fully treated of, and when a careful consideration has 

 been made of the comparative flows of migrants at Bell Eock and 

 the Isle of May, the latter being undoubtedly accepted as " The Key 

 of the Forth," whilst the former holds — to my present view — only 

 a doubtful or intermediate position, though prominent in itself as a 

 " house of call " for either or for both. These and similar questions 

 will no doubt receive solution before long. Mr. W. Evans, who has 

 devoted much thought to the Forth area, and is alive to the import- 

 ance of the Isle of May as a resort or rendezvous of migrants, will no 

 doubt help greatly to clear up any uncertainty still existing in such 

 matters. Meanwhile Bell Eock may remain as an isolated position 

 of influence, and during the present stage of inquiry has been left for 

 separate treatment. Just as no part of the Forfar coast, and no part 

 of the coasts north of the Tay estuary as far as Girdleness, can be 

 said to present a true " catchment " for migrants in any great or 

 prominent quantities, in the same way Tay fails to receive so large 

 a share of our usual migrants as Forth does. Especially must this 

 appear in evidence, if the main trend of the flights is — as has been 



