88 THE ZOOLOGIST, 



the buff of the former is at this season almost smoky brown, and 

 of the latter bright yellow, it is plain that the heads of the two 

 species would be much more distinct than if this variation 

 presented itself in the head of the immature autumn Sedge- 

 Warbler. I have mentioned that the distinguishing characters in 

 the ivhole plumage of the Aquatic Warbler — not only those of the 

 head — should be clearly pointed out. For if one is not well aware 

 of the fact that the two species in immature garb are quite distin- 

 guishable, apart from the head markings, one is liable to fall into 

 the error of thinking that a Sedge-Warbler, in which the medial 

 buff head line is broad, is an Aquatic Warbler. I must admit that 

 when I first obtained such a specimen of this type (fig. 4), I was 

 not quite sure that I was not in possession of another Aquatic 

 Warbler ; all the more so, because its date of capture followed 

 closely on the heels of that "of the genuine Aquatic Warbler 

 (fig. 5). However, by carefully comparing the bird with several 

 Aquatic Warblers, in addition to the one obtained on Tuskar, 

 I was able to refer this abnormally plumed Sedge-Warbler 

 to its proper position. My best thanks are due to Dr. Hartert 

 for affording me facilities to examine the fine series at Tring 

 Museum, and also for confirming my opinion as to the species. 

 In connection with this interesting question of variation in the 

 plumage of the head of the Sedge-Warbler, I have selected four 

 birds, together with the Aquatic Warbler from Tuskar, from 

 which I have made photographs. These serve to illustrate : — 

 The dark smoky buff and blackish streaked heads of the nuptial 

 and mature autumn plumages (fig. 1), a dark type of buff and 

 blackish streaked head found in some immature autumn birds 

 (fig. 2), the more usual light buff and blackish streaked head of 

 the immature autumn bird (fig. 3) ; and a further gradation in 

 which the medial buff streak is conspicuously broad and light in 

 colour (fig. 4) ; resembling the same in the Aquatic Warbler 

 (fig. 5). Sex appears to play no part in these variations, except 

 that there may be a slight tendency for the buff streaks to be 

 darker in the immature male than in the female. However, 

 it is interesting to note that fig. 4 is a photograph of a male 

 immature bird, in which it has been pointed out the buff on the 

 head is dominant and bright. Fig. 3 is a photograph of a female 

 bird with another variation, viz. barring of the tail. I have a 



