WARBLERS. 491 



The glossy black and chestnut colours of the male are replaced in the female by 

 dark brown and pale rufous. 



The grey warbler and its congeners (Gerygone) possess a slender 

 straight bill slightly curved and compressed ; the wings are rather 

 short and rounded ; the tail is long and rather rounded ; and the metatarsus long 

 and slender. The birds of this group are found in Australia and New Zealand, 

 ranging also to New Guinea and adjacent islands. The grey warbler 

 (G. flaviventris) is mentioned here, because it performs the function of a foster- 

 parent for the young of the two species of cuckoos found in New Zealand. It 

 is a bird of sombre plumage and unobtrusive habits, but utters at short intervals 

 a note of much sweetness; and is plentiful in every part of New Zealand, where it 

 appears to be as much at home in the woods as in the open scrub. Its food consists 

 of small insects, which it obtains in the leafy tops of forest trees as well as in the 

 dense foliage of thick bushes. Sir Walter Buller says : " In the Hot Lakes district 

 I have found it flitting round the steaming geysers, apparently unaffected by the 

 sulphur-fumes, and catching the minute flies that are attracted thither by the 

 humid warmth. Down by the seashore its note may be heard in the low vegetation 

 that fringes the ocean beach ; whilst far up the mountain-side, where the scrub is 

 scarce and stunted, it shares the dominion with the ever-present Zosterops. Its 

 sweet thrilling warble is always pleasant to the ear, being naturally associated in 

 the mind with the hum of bees among the flowers, anil the drumming of locusts in 

 the sunshine." The grey warbler is remarkable Tor the form of its nest, which is 

 a domed structure, belonging to one of two types — the bottle-shaped nest with a 

 porch entrance, and the pear-shaped form without a porch. The materials used in 

 nest-building are dry moss, grass, vegetable fibres, and spider-webs. The eggs are 

 white, often spotted with red. The grey warbler is an attentive parent to the 

 young of the cuckoos, which are foisted upon it ; and probably owes its preservation 

 to the fact that it builds a pensile nest, out of the reach of rats and other vermin. 

 The adult male is olive-brown above ; the sides of the neck are dark ashy grey ; 

 the tail feathers are ashy brown, shaded with black; and the throat, breast, and 

 sides cinereous grey. 



The True While the chats, redbreasts, nightingales, and other members of 



warblers. t ne subfamily RwticillinOB are included by Mr. Oates among the 

 Turdidce, the true warblers and their kindred are regarded by the same ornithol- 

 ogist as constituting a separate family, Sylviidce. On the other hand, Professor 

 Newton includes the Rat icillince in the Sylviidce; thus showing how very close 

 is the resemblance between the true warblers on the one hand and the thrushes on 

 the other. Accordingly, we prefer to follow Dr. Sharpe in including all those birds 

 under one great family, of which the true warblers will constitute a separate sub- 

 family (Sylviince). Having thus indicated how extremely difficult it is to separate 

 the thrushes and their allies from the true warblers (Sylvia), it may be mentioned 

 that the latter are generally of small size, and usually of plain-coloured plumage. 

 More insectivorous in their habits than the thrushes, and also more migratory in 

 their movements, they usually possess slender bills, adapted to the pursuit of 

 insects. Their wings are variable in size ; and the feet slender, and furnished with 

 tine toes. The young of the warblers, unlike those of the typical thrushes, do not 



