Passeres 33 



less abundant in the north than in the south and in 

 Ireland, and even breeds in Shetland, while abroad the 

 typical form ranges from Lapland and north Russia to 

 the Mediterranean, except for the Balkan Peninsula. 



The Chiffchaff (P. collybita), a more local bird, which 

 barely extends to northern Scotland, is only found in 

 its typical form from France and Germany southward 

 in Europe and is replaced east of the Volga by the 

 Siberian Chiffchaff, known also to breed in north 

 Russia. The Scandinavian Chiffchaff occupies north 

 and east Europe, and a smaller form is found in the 

 Canaries. The Wood Wren (P. sibilatrix) is the rarest of 

 our three species, and prefers oak woods and hill- valleys ; 

 it is a somewhat less northern bird than the Willow Wren, 

 but reaches the Mediterranean. All three are yellowish 

 green above and lighter below, with a yellow streak 

 over the eye, but the distinctly yellow breast of the 

 Wood Wren clearly distinguishes it from the other two, 

 in which the breast is yellowish white. The Chiffchaff 

 is duller and smaller than the Willow Wren with darker 

 feet. But, apart from plumage, they are easily recogni- 

 sable by their notes and breeding habits. The song of 

 the Willow Wren consists of a few sweet reiterated notes, 

 occasionally swelling into a song like that of the Garden 

 Warbler ; the Wood Wren, after a similar start, ends with 

 a long drawn trill; the Chiff chaff says "chiff-chaff" 

 most distinctly. The song is usually accompanied by 

 a quivering of the wings : the hens merely utter a 

 plaintive sound. The nests are oval balls of grass with 

 a side entrance ; but those of the Willow Wren and Wood 

 Wren are very seldom placed above the ground, while 

 that of the Chiffchaff is nearly always in a low bramble, 

 small shrub, fern or grass-tuft ; the Wood Wren lacks the 



E. B ?. 



