266 BRITISH BIRDS. [vol. x. 



However, Cliiffchaffs have also been recorded in tliis 

 country interspersing their normal song with a close repro- 

 duction of the Willow-Wren cadence ; whilst some at 

 least of the Chiffchaffs of the Iberian peninsula and a 

 proportion of those inhabiting south-west France have 

 a distinct song of the Willow-Wren type, although, so 

 far as I know, it has not been shown that the Iberian 

 Chiffchaff is worthy of even subspecific rank. It would 

 seem that the notes and songs of Phylloscoyi need careful 

 investigation in relation to their specific and subspecific 

 divisions. Can it be that, in the case of the Phylloscopi, 

 differentiation in call-notes and song is one of the first 

 signs of an " incipient variation " ? This would not 

 explain the unusual approximation of the call-notes of 

 Ph. i. trochilus and Ph. c. collyhita ; but it provides a 

 possible explanation of the unusual differentiation for 

 subspecies betw3en the call-notes of Ph. c. collyhita and 

 Ph. c. tristis, of Ph. t. trochilus and Ph. t. eversmanni, 

 and between the song of the Iberian Chiffchaff and that 

 of normal Ph. c. collyhita. I believe there is some diffei- 

 ence between the call-notes of the subspecies of Motacilla 

 flava ; but my limited experience does not provide any 

 other instance of a clear distinction between the call- 

 notes or songs of subspecies. 



I think it may be worth while to note that on the 12th 

 I saw a Swift {Apus a,, a pus) flying north-west about 

 9 a.m., and between 4 and 6.30 p.m. about thirty arrived 

 from the south-east and passed inland. On the 13th 

 we saw one again at noon, but we left soon after 2 p.m. 

 These were the only Swifts I had seen for weeks. From 

 observations made on that part of the coast and inland 

 in certain other years I am of opinion that this late east 

 to w^est migration of Swifts in September is a frequent, 

 if not annual, occurrence. The wind, which had been 

 fresh from the north-east from the 6th to 10th, and very 

 light on the 11th, was light from points between north 

 and west on the 12th and 13th 



