82 The Field Nattiralisf s Quarterly May 



have been shared by both G. A. Boulenger and Hans 

 Gadow, the latter of whose book on Amphibia and Reptiles 

 is noticed elsewhere. On p. 643 of that work Dr Gadow 

 says, referring to the adder, " They cannot climb, and they 

 avoid going into water." It is just one of those points which 

 the field naturalist of all persons has most opportunities of 

 settling, and we should be glad to have any other instances 

 of the occurrence reported to us. 



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How many field naturalists, we wonder, have any con- 

 ception of the complexity of the migrations of some of our 

 common birds ? Most of the information on the subject has 

 remained respectably buried in the reports of the British 

 Association, to which but few field workers have the oppor- 

 tunity of access. A case in point is the statement of Mr W. 

 Eagle Clarke to the Bird Migration Committee last year, 

 which deals with the " histories of the various migrations 

 performed annually within the British area by the skylark 

 and the swallow." The degree of migration in our native 

 skylarks is said to depend on the two factors of varying 

 climate and food-supply. Thus in the south-west of Eng- 

 land, and in Ireland, there is less migration than in other 

 parts which are more exposed to winter cold, and to such 

 districts the skylark is a summer visitor only. Mr Eagle 

 Clarke sums up these complicated movements under the 

 following headings, which will enable our readers to see the 

 great difficulty of the problem in the case of this particular 

 species : — 



The various migrations of the species may be conveniently separ- 

 ated and arranged as follows, beginning with the autumnal move- 

 ments ; and when it is considered that several of these movements 

 are often simultaneously in progress, some idea of their complexity 

 and the extreme difficulty of their interpretation may be realised : — 



1. Autumn Emigration of Summer Visitants, with their offspring 



— />., home-breeding and home-bred birds. 



2. Autumn Immigration of Winter Visitants from Central Europe. 



3. Autumn Immigration of Winter Visitants from Northern 



Europe. 



