CII1FFCHAFF. 439 



about the third week of April. My friend Gaetke writes to me from 

 Heligoland : " The Chiffchaff visits our rock in considerable numbers, 

 though not so frequently as the Willow- Warblers. It arrives earlier in 

 spring, and lingers later in autumn than any of its congeners, and does 

 not seem frightened of rough weather. The spring migration commences 

 as early as the end of March ; and the autumn migration continues into 

 November. It is somewhat remarkable that a bird which chooses such 

 cold weather for its migrations should not breed so far north as many other 

 AYarblers." 



The nest of the Chiffchaff does not differ from that of the Willow-Wren 

 or that of the Siberian Chiffchaff. It is semi-domed, composed of dried 

 grass, rather loosely made outside, but inside very neat and lined with 

 roots, horsehair, and finally with a profusion of feathers. Like that of 

 the Siberian Chiffchaff, but unlike that of the Willow-Wren, it is often 

 placed a foot or two from the ground. Occasionally, however, both the 

 Chiffchaffs breed in the grass on the ground. 



The eggs are from five to seven in number, and vary from pure white to 

 pale creamy white in ground-colour. There are two types of ChiffchafTs 

 eggs. The commonest type is spotted, chiefly at the large end of the egg, 

 with very dark reddish brown. Belonging to this type are certain varieties, 

 in which the markings are very minute and more evenly distributed over 

 the entire surface of the egg. In the second type the spots are very much 

 larger and likewise paler and not so numerous. Underlying spots of 

 violet-grey are seen sparingly in the eggs of this bird. The eggs vary in 

 length from '65 to '55 inch, and in breadth from '5 to '45 inch. 



The adult Chiffchaff in spring plumage has the general colour of the 

 upper parts olive-green, slightly yellower on the rump ; the eye-stripe is 

 somewhat ill-defined, and is greyish white, with a shade of yellow, and 

 extends only a short distance behind the eye ; the lores and the feathers 

 behind the eye are olive ; the wing-coverts and quills are brown, edged 

 on the outside webs with olive-green, and are emarginated as far as the 

 sixth. The quills are narrowly tipped with white ; and the tail-feathers 

 are brown, the outside webs edged with yellowish green, and the inside 

 webs with a narrow greyish-white margin. The general colour of the 

 underparts is white, shading into grey on the breast and flanks, and more 

 or less suffused all over with yellow ; the axillaries, under wing-coverts, 

 and thighs are yellow. Bill dark brown above, slightly paler below; legs, 

 feet, and claws dark brown ; irides hazel. The Chiffchaff suffers consi- 

 derably from abrasion during the perils of migration : the upper parts 

 fade into olive-grey; the eye-stripe and underparts lose some of their 

 yellow ; and the pale tips to the quills disappear. After the autumn moult 

 the whole of the plumage becomes suffused with huffish yellow, which is 

 almost pure pale buff on the eye-stripe, breast, flanks, and under tail- 



