Introduction: Migration. 



51 



Two or three individuals often make their appearance in the daytime in the 

 Bismarckplatz in the town each year, though they are not always driven there 

 by cold and hunger, and they are most likely the same birds each season. 

 There is an autumnal migration roixte of Wild Geese [Anser segetum) at Grossen- 

 hain near Dresden, the birds making their appearance during their transit to the 

 South every year on the fish-ponds at this place, but only quite exceptionally on 

 the fish-ponds at Moritzburg some 10 miles to the S.E. Mr. Schwarze of the 

 Dresden Museum informs us that Kingfishers did not occur in summer at his 

 native village in Saxony , but were to be found every winter, when the fish- 

 pond was frozen over, at the inlet or trap where water was let in, and where 

 there were plenty of small fish. The Grey Crow, Corvus comix L., visits the 

 Eastern counties of England in great numbers every autumn; these birds do 

 not proceed far inland, being unknown in the Western counties; and such is 

 almost equally the case in the Southern Midlands, for instance, in Northern 

 Buckinghamshire. Yet these parts of England appear to be quite as capable 

 of sustaining them as the Eastern counties. Mr. W. Eagle Clarke's "Digest 

 of the Reports on Migration" should also be read in this connection. 



If the birds remember their final and intermediate halting-places so well, 

 it appears that they must find their way in migrating by means of such familiar 

 land-marks and stations. It is well known that "homing" Pigeons are lost if 

 turned out in a strange country, and these birds are trained for long flights by 

 breaking the journey into a number of stages and thus gradually lengthening 

 the familiar landscape. In the same way it can well be understood how such 

 a bird as Phylloscopus borealis, which migrates from Norway across Siberia to 

 the East Indies, may originally have been a native of East Siberia, but extended 

 its breeding range for a mile or two at intervals, the advanced individuals 

 flying back over the known track to their comrades in autumn; while the 

 young generation gathered experience from the older travellers, and thus the 

 ancient traditional route was increased in extent. 



Nevertheless it should be pointed out that Professor Newton, who was 

 one of the first to examine the "homing" faculty of Pigeons in the hope that 

 it might aff"ord a clue to explaining how migrating birds find their way, has 

 since been led to abandon it, holding that ocular memory as the guiding medium 

 is disproved by three facts; first, that migrating birds fly over the open sea, 

 sometimes thus traversing as much as a thousand miles before they can reach 

 land; secondly, that much migration is done in darkness at night, sometimes at 

 high elevations; thirdly, that "among migrants the young and old always journey 

 apart and most generally by difl'erent routes". These reasons may well be con- 

 sidered beyond all objection by many ornithologists, but by others not so. A 

 bird may take its direction across the vast open expanses of the Pacific, as has 

 been already remarked, by means of the familiar lay of the land at starting, 

 the rise and setting of sun and stars, and, as Prof. Mobius has suggested, by 

 the direction of the roll of the waves; also by ascending to a height of 10 000 



