CHAPTER XI. 



INTERNAL MIGRATIONS AND LOCAL MOVEMENTS IN 

 THE BRITISH ARCHIPELAGO. 



Meagreness of Data bearing on this Question — Local Movement 

 in Spring and Summer — Internal Migration always takes 

 place within Normal Areas of Dispersal — Birds do not Wander 

 from their Areas — Comparative Movements of the Snow 

 Bunting, the Northern Bullfinch, and the Crested Titmouse — 

 Emigration only Undertaken during the Season of Reproduction 

 —Local Movement amenable to Law — Effects of Severe 

 Winters on Birds— Results of such Movements ineffectual in 

 extending Area — Redwings and Severe Weather — The Want 

 of carefully-kept Records — Local Movements at Lighthouses 

 — Irruptic Movements — Their Futility as Colonizing Agents. 



We cannot well dismiss the stibject of Migration in the 

 British Islands without some brief allusion to all those 

 local movements of birds that take place within that 

 area. The subject is a much more difficult one than 

 might be suspected. Unfortunately at present the data 

 arc too meagre to allow of much accurate generalization 

 or deduction. A vast amount of observation has been 

 made, but the haphazard way in which the facts have 

 been collected is a very serious detraction from the 

 value of such observation. Notwithstanding the ap- 

 parent fortuitous character of much of this internal 



