64 GEOGRAPHICAL DISTRIBUTION 



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 involuntarily 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 impos- 

 sible 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 "distribution of the species. Many 

 species which can now only be regarded as accidental visitors to 

 our Islands were regular Summer Visitors 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 Resi- 

 dents 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 Scandi- 

 navia 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. I have endeavoured to ascertain in the various species 

 which predominate the residents or the winter visitors, and to 

 allot them accordingly. 



It is obvious that some species may belong to one category in 

 England and to another in Scotland or Ireland. For example, 



