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CHIFFCHAFF, 439 
about the third week of April. My friend Gaetke writes to me f rom 
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 1s somewhat remarkable that a bird which chooses such 
cold weather for its migrations should not breed so far north as many other 
Warblers.” ; 
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-W ren, it is often 
placed a foot or two from the ground. Occasionally, however, both the 
Chiffchafts 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 Chiffchaft’s 
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 scen sparingly in the eggs of this bird. The eggs vary in 
leugth 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 buffish yellow, which is 
almost pure pale buff on the eye-stripe, breast, flanks, and under tail. 
