284 THE BIRDS OF HELIGOLAND 



In general appearance, this and the preceding species closely 

 resemble one another ; on a close examination, however, it is im- 

 possible to confound the two species — for in the Siberian Chiffchatf, 

 the greyish-brown upper parts have scarcely a touch of the fresh 

 ohve colour peculiar to the common Chift'chaff, while the lower 

 parts show not even the least trace of the vivid light yellow colour 

 of the latter species. The neck, upper breast, and the sides of the 

 breast are of a dull light rust colour, almost isabelline — whitish rust- 

 gi-ey in the faded sunnner plumage — and only the under tail-coverts 

 display the pretty yellow coloration characteristic of the Warblers. 



The first authenticated observations on the nest and eggs of this 

 species were made b}' Seebohm during his interesting and success- 

 ful expedition to the Lower Jenesei (v. Siberia in J..sia, pp. 152 and 

 173). One of the eggs, which was taken in that district on the 15th 

 of July 1877, in latitude 70i° N., and is in my possession, resembles 

 in its fine dark dotted markings the eggs of St/lvia rufa, but is 

 somewhat larger than the average measurements of those of the 

 latter species, though the bird itself is usually of smaller size. 

 The egg in question is '07 in. (17 mm.) long, -51 in. (13 mvi.) 

 broad ; accordingly, of less roundish form than the eggs of riifa and 

 trochilus. It is pure white, and the reddish-black dots are sparingly 

 scattered over the whole surface, though they are disposed some- 

 what more densely in a kind of wreath or corona at the thick end 

 of the egg. 



Seebohm and Harvie-Brown met with this bird at the beginning 

 of July 1875 on the Lower Petchora; one of Dybowsky's skins, 

 which is in my possession, is dated Lake Baikal, June 18th ; 

 therefore we may probably assume that this species breeds through- 

 out the whole of northern Asia. 



108. — Dusky Tree Warbler [Brauner Laubvogel]. 

 SYLVIA (PHYLLOSCOPUS) FUSCATUS, Blyth.i 



Dushj Tree Warbler. Jerdon, Birds of India, ii. 191. 



My garden is divided from that of my neighbour by a high 

 wooden paling, and it gives me much pleasure to watch through 

 the chinks the doings of the birds there, who, utterly un- 

 aware of being watched at a distance of a few feet, move about 

 in their most natural and unconstrained manner. In this waj', 

 on the 24th of October 1876, I espied close to me a small 

 Warbler which, as regards the colour of its plumage, might have 

 been described as the most advanced stage of a very vividly 



' Lusdniola fiiscata (Blyth). 



