DISTANCES TRAVELLED BY BIRDS 71 



southern birds first passing the northern, and the 

 northern passing them in turn " (20). 



The custom, now fortunately becoming wide- 

 spread, of marking birds by affixing a numbered 

 metal ring to one leg, may help to elucidate this and 

 many other problems, but until a large number of 

 results are collected it is unwise to draw conclusions. 

 Almost every month the recovery of some of these 

 marked birds is noted in the scientific journals, but 

 so far, beyond indicating the minimum distance 

 travelled by individuals, little can be proved. It 

 is, however, plain that birds do not invariably act 

 as they ought to do if they obeyed all the laws which 

 have been invented for them. A few records or 

 results may be quoted, but any suggestions from 

 these must be treated as suggestions only ; many 

 more must be forthcoming before we can say, 

 proved. 



The white stork, Ciconia alba, has been systemati- 

 cally ringed in Rossitten in East Prussia, in Denmark 

 and in Hungary for some years, and Mr A. L. Thomson 

 gives a brief summary of the interesting results up 

 to date, in "British Birds" for May, 1911. Ten 

 young birds, taken during their first autumn journey, 

 show a general south-easterly trend through Europe. 

 Three east Prussian storks were obtained in Syria, 

 one in the April after it was marked, the other two 

 in April and July of the second year ; another was 



