BIRDS OF TASMANIA. 39 



*YELLOW-RUMRED TIT (YELLOW-TAIL) 

 (Acanthiza chrysorrhoa, Quoy and Gaim.) 



Male. Forehead black, each feather tipped with white; upper 

 surface, including wings, olive-brown ; rump and upper tail coverts 

 bright citron-yellow ; base of tail feathers yellowisn- white, central 

 portion blackish-brown, then a short tip of greyish-white; chest 

 and under surface yellowish- white, passing into light olive-brown 

 on the flanks ; bill, legs, and feet blackish-brown. Dimensions in 

 mm. : Length, 106; bill, 9.75; wing, 59; tail, 46; tarsus, 17. 



Female. Similar to male. 



Nest. A bulky, elongated structure, divided into two parts. 

 The nest proper is closed in, with a spouted side entrance ; above 

 this is a semi-nest, open back and front. Dry grasses and wool are 

 usually the chief materials employed ; the lining is either wool 

 alone or wool and feathers, a thick layer being used. The situa- 

 tion varies, but as a general thing the drooping boughs of a moder- 

 ately low to low tree, or near the centre of a gorse bush, is chosen. 



Eggs. Clutch three to four or even five; long oval in shape; 

 texture very fine; surface glossy; colour pure white, without mark- 

 ings, but sometimes a few tiny spots of dull red appear on the apex. 

 Dimensions in mm. of a clutch : (1) 18 x 12.5, (2) 18.5 x 13, 

 (3) 18.25 x 13, (4) 18 x 12.5. 



Breeding Season. August to December. 



Geographical Distribution. Tasmania, New South Wales, Vic- 

 toria, Queensland, South and Western Australia. 



Observations. This bird is popularly known to most under the 

 name of Yellow-tail. It is widely distributed throughout the island, 

 and is perhaps the commonest of the Acanthizce. It is also very 

 common during certain seasons of the year in suburban gardens. 

 This more particularly applies to the winter months, when its 

 natural food is running short and competition is very keen among 

 its feathered congeners for anything in the shape of provender. 

 The object of the upper or false nest has been the subject of much 

 discussion. Many and varied opinions and theories have been 

 advanced from time to time as to its real object s,nd utility. The 

 most generally accepted theory is that it serves as a roosting-place 

 for the male at night while its mate is engaged in the task of 

 incubation. Another theory is that it acts as a blind to enemies, 

 for, on finding an empty space, they naturally conclude that the 

 nest is vacant, and so do not investigate further. Yet another 

 theory is that it serves as a shelter for the young when grown too 

 big for the nest proper but not yet able to shift for themselves. 

 Often have I found a nest containing the first clutch of eggs of the 

 season and the upper apartment showing signs of having been 

 used. I do not see any reason why the three theories should not 

 dove-tail one into the other, and the upper structure come in 

 for all three purposes viz., a blind to enemies, shelter for the 



