468 



SCOLOPAX. 



Absence of 

 Snipes in 

 Australia. 



Extraordi- 

 nary deve- 

 lopment of 

 tail-feathers 

 in East 

 Siberia. 



cannot be much doubt that it was once a resident in Japan, nor can there be any doubt 

 that a change in the habits of a bird from being a resident to being a migrant, whose range 

 of migration covers a distance of five thousand miles, soon produced a corresponding change 

 of structure. Its rounded wings and exceptionally long and heavy bill must seriously have 

 impeded its progress, and we may confidently assume that Nature soon lengthened the one 

 to aid its powers of flight, and shortened the other so that it might have less weight to 

 carry. What I wish to infer from this argument is the strong probability that Latham's 

 Snipe, before it became a migratory bird, differed scarcely, if at all, from the present 

 condition of its allies in Madagascar and Colombia. The cold of the Glacial Epoch not 

 only forced it to winter in Australia, but so reduced the area of its breeding-grounds, that 

 large bodies were compelled to emigrate in search of fresh ones, as Pallas's Sand-Grouse 

 did in 1863. It is difficult to say why they did not stop in Australia and breed there ; 

 but there must be something either in the climate or food of that continent which does not 

 suit the true Snipes during the breeding-season, as none of them are known to breed in 

 Australia. But, be that as it may, one party of emigrants seem to have flown almost due 

 west to find a suitable home in Madagascar, whilst another must have flown almost due 

 east to secure excellent quarters in Colombia. The birds which founded these two colonies, 

 having discovered situations suitable for both summer and winter residence, probably 

 neither changed their habits nor their structure. Their descendants are probably almost 

 identical in form and colour with the common ancestors of the three forms when they were 

 residents in Japan, and that is probably the explanation of their remarkable similarity at 

 the present day. They have never passed through the ordeal of annual migration or been 

 subjected to the sifting process involved in the non-survival of the least fit to endure the 

 perils of such journeys. The alternative hypothesis that the Japan bird has retained its 

 characters, and that the Madagascan and Colombian species have changed, is open to the 

 objection that it seems impossible that two colonies so remotely situated could have 

 independently varied in the same direction to a similar extent. 



There is one very remarkable fact connected with the Snipes, and that is that the 

 number of tail-feathers appears to vary in distinct connection with geographical distribu- 

 tion, as if it was a climatic rather than a genetic variation. Those inhabiting Europe, 

 Africa, and America have fourteen to sixteen tail-feathers, whilst those peculiar to 

 East Siberia have from eighteen to twenty-six. This extraordinary development of 

 additional tail-feathers in East Siberia is very remarkable, and is not confined to the 

 Snipes. Two species of Ground-Thrushes, Geocichla varia from East Siberia, and 

 67. horsfieldi from Java (the latter obviously the result of a comparatively recent 

 emigration from the former), are distinguished from all other Thrushes by having fourteen 

 instead of twelve tail-feathers ; and the Sea-Eagle of Kamtschatka also stands alone 

 amongst his confreres as the possessor of fourteen tail-feathers. It is perhaps impossible 

 to discover any rational explanation of these curious facts. Modern evolutionists have 



