( 195 



ON THE MOUTH-COLORATION OF SOME 

 NESTLING BIRDS. 



BY 



ANNIE C. JACKSON. 



Having read, with interest, Mr. Pycraft's article on the 

 colouring of the inside of the mouths of nesthng birds in 

 British Birds for October, 1907, I determined, if possible, 

 to make some observations during the following spring ; the 

 more so, as but little material seemed to have been collected 

 on the subject. I now give the results of my observations, 

 which seem to prove that the spotted type of mouth in 

 nestlings is far from common. 



Unfortunately, I was not able to examine any of the Tit 

 family ; for nesting as they do in crevices and holes it is 

 difficult to reach the young birds. I was struck with the fact 

 that all the downy chicks of the Order Limicolce which 

 I have had the opportunity of examining, had very in- 

 conspicuously coloured mouths. But before one can draw any 

 conclusions as to the significance of this, it will be necessary 

 to have a complete list of the colouring of the inside of the 

 mouths in nestling birds of the helpless type. 



Mistle-Thrush. — Mouth (inside), yellow, unspotted. 

 Flanges (outside), pale yellow. Nest well lighted. 



Song-Thrush. — Mouth (inside), orange-yellow. Flanges 

 not nearly so large and conspicuous as those of the young 

 Starlings. Nest well lighted. 



Whitethroat. — Mouth (inside), yellow, with a dark semi- 

 circular band stretching from one spur of the tongue to the 

 other. The band should rather be called " dusky," than 

 black. 



Willow- Wren. — Mouth (inside), unspotted yellow. Nest 

 well lighted. 



Wren. — Mouth (inside) and flanges very pale lemon-yellow, 

 unspotted. Nest badly hghtecl. 



Tree-Creeper. — Mouth (inside), yellow, unspotted. The 



