6o 
British Birds. 
Pallas’s Willow-Warbler. 
PALLAS’S 
WILLOW- WARBLER. 
(Phylloscopus proregulus.) 
yellow eyebrow, and the under surface of the body 
is ashy whitish, with a few streaks of yellow on the 
breast, and the flanks are greenish, washed with 
yellow. 
In Siberia the present species was found by 
Seebohm frequenting the pine-forests, where it was 
very common. The nest was made of dry grass 
and moss, and lined with reindeer hair, and 
resembled that of the British Willow-Warbler, 
being half domed. The eggs are white, spotted 
with reddish-brown, more plentifully towards the 
larger end. 
This species inhabits South-eastern Siberia as well as 
the Himalaya Mountains, and occurs in winter in the 
Burmese provinces and Southern China, visiting South- 
eastern Russia in the autumn migration. It resembles the 
preceding species, but has a yellow rump, which is in strong contrast to its greenish 
back. It has the same pale streak down the crown and the double wing-bar as in 
P. superciliosus. Although its presence has twice been detected in Heligoland, it 
has been noticed but once in England, a specimen having been shot near Clay, in 
Norfolk, on the 31st of October, 1896. Like the Yellow-browed Warbler, the present 
species frequents the pine-woods, and places its nest, which is slightly domed, on the 
branch of a tree near the stem of the latter, the outside of the nest being covered 
with moss and lichen, so as to resemble the colour of the branch on which it is 
placed. The eggs are five in number, white, richly spotted with dark brownish-red, 
the spots collecting towards the larger end. 
The Tree- Warblers are somewhat intermediate between 
the Willow-Warblers 
and the Reed-Warblers. 
They have a more flat- 
tened bill than the Phylloscopi, and on each side 
of the gape are three weak rictal bristles. The 
two species which concern us are clear yellow 
underneath, and this character, along with the 
shape of the bill, with its yellow under mandible, 
is sufficient to distinguish both the British Tree- 
Warblers from the members of the allied genus 
Phylloscopus, while the pattern of the eggs is 
quite different. 
The Common Tree-Warbler has been noticed 
in England apparently about eight times, and The Common Tree-Warbler. 
THE COMMON 
TREE-WARBLER. 
(Hypolais hypolais.) 
