THE TREE-WARBLERS. 217 



sat down upon a tree-trunk to watch. The bird was very un- 

 easy, but continually came back to a birch tree, from which it 

 frequently made short flights towards the ground, as if it were 

 anxious to return to its nest, but dare not do so whilst we 

 were in sight. This went on for about half an hour, when we 

 came to the conclusion that the nest must be at the foot of the 

 birch-tree, and we commenced a second search. In less than 

 five minutes I found the nest, with six eggs. It was built in a 

 slight tuft of grass, moss and bilberries, semi-domed, exactly 

 like the nest of our Willow-Warblers." 



Nest. — Composed of dry grass and moss, and lined with rein- 

 deer-hair, according to Mr. Seebohm. 



Eggs. — The above named author describes these as having the 

 ground-colour pure white, spotted very thickly at the large end, 

 in the form of an irregular zone, with reddish-brown, and more 

 sparingly on the remainder of the surface ; some of the spots 

 underlying and paler, but not grey, and on one or two of the 

 eggs they are confluent. Axis, o*6 inch ; diam., 0*45. Mr. 

 Seebohm remarks: "The markings are well-defined, like 

 those on the eggs of the Chiffchaff ; but the colour is decidedly 

 more like that of the Willow- Warblers, while they approach 

 much more closely the eggs of the Indian Willow- Warbler, P. 

 humii % both in colour and size." 



THE TREE-WARBLERS. GENUS HYPOLAIS. 



JTypolais, C. L. Brehm, Isis, 1828, p. 1283. 



Type, H. hypolais (L.). 



Certain groups of Warblers have a typical coloration of 

 egg, known to every ornithologist. Thus anyone can tell the 

 peculiar egg of a Cettia, which is of a brick-red colour, and this 

 style of coloration runs through the eggs of all the species 

 allied to Cetti's Warbler. The same may be said of the mem- 

 bers of the genus Hypolais, for the eggs of these birds are 

 equally peculiar, having the ground-colour of a purplish-grey or 

 salmon-pink. All the members of the genus are like Willow- 

 Warblers in general aspect, but they have a much longer and flat- 

 ter bill, approaching that of the Reed-Warblers (Acrocephalus) in 

 shape, and havingthree weak rictal bristles, with somesupplemen- 



