OF BRITISH BIRDS. 5 



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in summer are called Residents, though many of them migrate from one part 

 of the country to another part in spring and autumn. Those birds which 

 visit us in spring, remain Avith us during their breeding-season^ but leave us 

 again in autumn to winter in more southerly climes^ are called Summer 

 Visitors. Those which vi^it us in autumn^ remain with us during the 

 winter, but leave us again in spring to breed in more northerly climes, 

 are called Winter Visitors. A fourth group consists of species whose 

 breeding-grounds are further north than the British Islands, and whose 

 winter-quarters are further south, and which consequently are only found 

 in our Islands for a few weeks during migration in spring and autumn. 

 They are called Spring and Autumn Migrants. 



The fifth group is a very large one and contains all those waifs and 

 strays which are supposed to have wandered out of their usual track to 

 our shores, some of them being adult birds that have been driven in- 

 voluntarily out of their ordinary course by storms and contrary winds, but 

 most of them being very young birds which have accidentally joined the 

 wrong batch of migrants, and have thus been led astray on their first trip, 

 or have lost their way in attempting to find it alone on their second trip. 

 These are called Accidental Visitors. 



It is impossible to draw a hard-and-fast line between these various 

 groups, and it must frequently be a question of individual judgment to 

 decide the exact group to which some species ought to be referred. 



The Accidental Visitors blend, on the one hand, with the Winter 

 Visitors, and on the other with the Summer Visitors, It is impossible to 

 fix any number of records per year or per century that ought to entitle 

 a species to be removed from the list of Accidental Visitors to those of 

 occasional, very rare, rare, or regular Winter or Summer Visitors. Any 

 line that is drawn between one group and another must of course be 

 arbitrary, and subject also to change with the changed geographical dis- 

 tribution of the species. Many species which can now only be regarded 

 as accidental visitors to our Islands were regular Summer Visitoi^s not a 

 century ago ; and some species which were regarded as accidental visitors 

 a century ago appear to have recently extended the range of their breeding- 

 grounds in a westerly direction, and occur so frequently upon our coasts 

 in autumn that they may now be included in the list of Winter Visitors. 

 The Shore Lark and Richard^s Pipit are cases in point. 



The boundary-line between the Winter Visitors and the Residents is quite 

 as difficult to draw. The number of Woodcocks which visit us in autumn 

 is doubtless very largely in excess of the number which breed in this 

 country ; and great numbers of birds of the same species as many of our 

 residents arrive from Scandinavia at various points on the east coast to 

 winter here. Probably the number of more than half of our so-called 

 resident species is increased by visitors from the Continent during the 

 ^ autumn migration. 1 have endeavoured to ascertain in the various species 



