XVI INTRODUCTORY. 



such an insect, that such and such a bh'd may be 

 exjDected to feed on it. Such a conjunction can only be 

 found in few individuals ; but if every man in his leisure 

 field-walks would— especially in connection with meteoro- 

 logical conditions — note the other natural circumstances 

 at the time of his first seeing a spring arrival, a mass of 

 information would be got together which might be in- 

 valuable for the discovery of the laws of geographical dis- 

 tribution. Until something of the sort is done, and such 

 information sifted and compared, I believe those laws 

 will remain, as they are now, dubious and conjectural. 



The winter migrants, or more especially those species 

 which visit our shores periodically in autumn and 

 spring, are easier of observation, and the British 

 Association Committee above mentioned have already 

 been able to indicate some probable results as to their 

 lines of flight and the causes of their movements. 



Although few of the Geese, Ducks, Tringae, &c., 

 which breed in the north, fail to visit the Lancashire 

 coast, on their passage to and fro, in small numbers, the 

 large flocks which are seen on the coasts of Yorkshire, 

 Norfolk, and the east generally, are not found on the 

 west, and the streams of migrants there are mostl}' 

 composed of species which breed in Scotland, Iceland, 

 and Greenland, Scandinavian and Siberian forms being 

 very irregularly represented. 



Results from Lancashire lighthouses, too, are small, 

 and indeed seem to be fewer now than formerly. Mr. 

 W. A. Durnford {ZooL, 1876), remarking on a Kingfisher 

 which was killed by flying against that on the south end 

 of Walney Island, says that the light-keeper told him 

 that thirty years before it was not unusual for 100 birds 

 to kill themselves against the glass in a single night, 

 whilst during the previous six months a Stock-Dove and 



