48 ON THB NATURAL HISTORY OP THE NIGHTINGALE. 



of the passes of the Pyrenees, and many, perhaps, coasting along 

 just to the interior of the shores of the Bay of Biscay ; these latter 

 continuing their course overland, from about Rochelle, till they 

 arrive at the channel, which, in consequence, they must cross, 

 chiefly at its narrower, or eastern limits ; being even on this ac- 

 count less likely, when making for our shores, to be borne away by 

 adverse winds, and distributed much to the westward of the point 

 from which they took their departure, than those species which are 

 more discursive in their seasonal journeys, and of which many indi- 

 viduals appear to cross from the westernmost extremity of Brittany. 

 Admitting, then, this to be the route of the Nightingales which 

 traverse the eastern parts of Spain, and that, as appears most pro- 

 bable, these deviate but a very little indeed, either to the right or 

 left, we are by no means surprised to find that this bird is un- 

 known in Le Bugey, and other districts of the south-east of France, 

 and we are prepared to hear of its not occurring in the west of 

 Brittany, and (excepting as an occasional straggler) to the west- 

 ward of at most the third degree of longitude in the British islands. 

 It is to be regretted that good local continental faunas are, at jjre- 

 sent, so rare, and difficult of access, and that, accordingly, we have 

 as yet so very few data for determining, in a satisfactory manner, 

 the exact routes, and consequently the precise geographical range, 

 of our numerous migratory birds. 



General distribution of the summer migrant birds over the British 

 islands. — We are not, however, by any means, hence to infer, of all 

 the species, that their migrations take place so nearly in a meridional 

 line as those of the Nij^htingale ; for some of them, as many of the 

 Warblers, appear to follow, pretty closely, the course of rivers, 

 along the different vallies; while others, as the common Wheatear^ 

 seem everywhere to frequent more the upland grounds, each pursuing, 

 thus, the range of its particular haunts, so long as this does not too 

 much interfere with its direct route. Of their general distribution 

 in our own islands, I think it probable (as we have already seen) 

 t^at by far the greater number cross over at the narrower portion 

 of the British channel ; and that, afterwards, when arrived upon 

 our shores, the less discursive kinds (indeed, the majority of them 

 all) continue their course northward, rather than disperse towards 

 the west; so that all are commonest in the south-eastern counties, 

 while a few species hardly visit at all, or very sparingly, the ex- 

 treme west of England, and the south of Ireland : those, indeed, 

 that do, being in all probability the individuals that had crossed 

 over from Brittany, a district which I more than suspect is never, 



