President's Address. 311 



above sea-level. But the primary reason why they do not 

 come within the influence is because they do not, in normal 

 migration, rise high enough to come opposite these central 

 rays. 



The above remarks apply equally at the several principal 

 points where great concentration of the migrants takes place. 

 Applying them more directly to the Firth of Forth we would 

 state it thus : " While comparatively few birds fly across 

 the cliff-edges of Berwickshire, but pour in vast streams up 

 the open Firth, at the same time, in easterly winds, especially 

 if high, birds are often borne numerously over the tops. In 

 normal westerly winds, however, migrants which pour up 

 this great channel throw off their thousands out of their tens 

 of thousands wherever the lower-lying shores are arrived at 

 inside of the Firth, and the ' return ' in Spring is equally 

 apparent." Thus the interior of Scotland, south of the Firth 

 of Forth, is mainly populated by migrants in Autumn via 

 the Firth of Forth; detachments, however, entering the 

 country at Berwick, and probably smaller detachments at 

 the mouth of the Haddingtonshire Tyne. Hence is it that 

 w^e find the south shore of the Firth of Forth populated by 

 autumnal flocks of w^aders, and by the return, but smaller, 

 flocks in Spring. We look upon the Isle of May as the 

 northern extension, along with, probably, Bell Eock and the 

 Tay, and a portion of the Forfarshire coast, of the waves 

 which cross from the direction of Heligoland. We do not 

 look upon these statements as theoretical now, but as almost 

 proven in their general accuracy; any occurrences to the 

 contrary being the exceptions which prove the rule. 



Beyond the above remarks I do not purpose venturing very 

 far here, though there are more abstruse questions which are 

 forced upon the students of migration. We will merely in- 

 dicate these. There are curious facts concerning the early 

 advent on our shores of the young of the year, of many 

 species, as compared with the later advent of the adults, 

 which are still veiled in comparative obscurity. There are 

 questions of Extension of range of species dependent upon 

 abnormal seasons of migration, which are stiU somewhat 

 intricate and uncertain, but concerning which, the correct 



