310 Capt. H. Lynes on the Geographical Distribution 



materiol was quite inadequate for the purpose. I am, 

 therefore, only able to present the very incomplete affair 

 shown in the map (PL XII.), upon which I would offer the 

 following remarks : — 



Northern Winter Limits, 

 The following generalities may perhaps be considered 

 fairly well substantiated : — 



Chiffchaff, — All over the Mediterranean littoral, but not 

 the cold inland regions behind the northern shores, and 

 on the western coasts of Europe, so far north as the warm 

 influence of the Gulf Stream pushes the Mediterranean 

 isotherms to the north-east there. It is clearly a matter of 

 temperature ; the most northerly-wintering individuals of 

 the species evidently keep quite close to the bare possibilities 

 of their insect food. 



Willow- Warbler. — Quite different to the Chiffchaff in 

 winter requirements, as its most northerly members only 

 just touch the south-west end of the Mediterranean. 



(The authority for Provence is too good to be disregarded, 

 and is presumably supported by specimens, but it. must 

 surely be a little exceptional, with no other, or negative, 

 records for so great a distance around it.) 



Southern Breeding Limits. 



These are so ill-defined than no generalization can be made, 

 but the following remarks are offered : — 



Chiffchaff. 

 PortuyaL — Given in a general way by Tait. But how far 

 south ? We know it breeds (the one with the curious song 

 and eggs) in numbers at Gibraltar, but there seem to be 

 no records of breeding elsewhere in Andalusia. Abel Chap- 

 man and I were constantly in cork, ilex, and pine woods 

 from the Sierra Nevada to Jerez (March, April, and May 

 1910, vide ^Ibis,' 1912, p. 454) and never found the suspicion 

 of a Chiffchaff breeding at any altitude, or, for the matter 

 of that, in a short visit to the chestnut and oak woods of 

 north-west Estremadura at the end of May 1910. 



