440 



BRITISH BIRDS. 



coverts. The huffish yellow pervading the whole of the autumn plumage 

 is never entirely lost by abrasion in winter. 



The Chiffchaff may be distinguished from the Willow- Warbler by its 

 wing-formula. In the present species the second primary is intermediate 

 in length between the sixth and ninth ; whilst in the Willow- Warbler it 

 is almost invariably between the fifth and sixth. A further distinction 

 may be found in the almost black legs of the present bird and its browner 

 plumage. 



