THE INSURGENCE OF LIFE * 167 



pipers, the great snipe, and the little stint. They rest 

 for a short time only in a country like Britain, on their 

 way further south or further north. 



(4) Then there are the ( partial migrants ', who are 

 always represented in the country or area in question, 

 but not always by the same individuals. That is to say, 

 some individuals leave the country and others do not ; 

 and the place of those who go is often taken by other 

 individuals from elsewhere. Thus in many parts of Scot- 

 land one may see lapwings every month of the year, 

 and yet there is a regular autumnal migration of lapwings 

 from Scotland to Ireland. There are always goldfinches 

 to be found in the South of England, but there is a regular 

 migration southwards in October and a corresponding 

 return in April. Kecent research has shown that the list 

 of ' partial migrants ' is a long one, longer than used to 

 be thought. 



(5) There remain the strictly resident birds such as, 

 in Britain, the red grouse and the house sparrow (to take 

 a sacred and a profane example). The rook and the robin 

 may serve as two other instances. But the list has been 

 greatly reduced by the discovery that many of the reputed 

 residents are really partial migrants. It is obvious that 

 no hard and fast line can be drawn ; and it goes without 

 saying that species which are resident in one country 

 may be migratory in another, just as the summer- visitors 

 of one country are of course the winter- visitors of another. 



Perhaps another division should be made for the inter- 

 esting ' casual vagrants ' who occasionally turn up in a 

 country, far ofi their normal line of movement. The 

 American Kildeer Plover shot in Aberdeenshire in 1867 

 is a good instance. 



