10 The Naturalist in Siluria. 



THE GEOGRAPHICAL DISTRIBUTION OP BIRDS. 



The purpose of this note is to point out the difficulty 

 of determining the boundary within which certain birds 

 may be found, especially the smaller sorts. The most 

 assiduous observer, ever on the watch, will now and then 

 discover a species in his immediate neighbourhood 

 whose existence there he had never before noted nor 

 suspected. Yet it did exist may even have nested and 

 bred in his own grounds, within a hundred yards of his 

 house. Were it not for their song or call-note betraying 

 their presence, many of the migratory birds our summer 

 visitants would come and go without the ordinary 

 observer, and in some cases the ornithologist himself, 

 being the wiser of it. For these are with us only when 

 the trees are in full leaf, to screen them from curious eyes 

 a screen most of them know the advantage of, and 

 take. You may hear the blackcap and garden warbler 

 giving out their dulcet notes every day, and hour after 

 hour, yet never get sight of either of these superb song- 

 sters, though perched upon a spray within less than a 

 rod's length from the spot where you are standing. But 

 it is not alone with our summer visitants that there is 

 this difficulty of fixing the home and habitation. It also 

 exists, to a greater or less degree, as regards the winter 

 ones, and even our permanently resident species, who 

 have no tree foliage to hide behind. I speak more par- 

 ticularly of the smaller kinds, from having lately met 

 several instances in point: by the discovery of species in 

 my own neighbourhood, whose existence in it I had long 

 doubted. Yet had they been there, as I now know, their 

 presence becoming ascertained almost by accident. 



A bird of sparrow size, seen at a hundred, or even 



