AQUATIC WARBLER ON MIGRATION. 85 



the Aquatic Warbler. In both species the bastard primary is 

 very small, while the third primary is the longest and shows 

 emargination of the lower end of the outer web. The length of 

 the wing, measured from the carpal joint to the extremity of the 

 longest flight feather, corresponds to the average wing-length of 

 the Sedge- Warbler. Compared with a number of Sedge- 

 Warblers, I found that the beak was a shade shorter and a trifle 

 more robust at the base. The colour appears to be the same in 

 both species, e. g. upper segment and distal half of lower 

 segment dark brown, proximal half of lower segment horn- 

 brown. The feet and toes, much the same length in both species, 

 are lighter in shade in the Aquatic Warbler and exhibit a light 

 flesh tint; in the Sedge-Warbler the shade is horn-brown. 



So much then for the external distinguishing characters in 

 the two species. As already mentioned, it is the broad buff 

 stripe running in a sagittal direction from beak to occiput which 

 ornithologists seem to have paid most attention to, and have at 

 the same time taken little account of the difference of the rest 

 of the plumage. Saunders, for instance, in his 'Manual,' states 

 that "the conspicuous buff streak down the middle of the crown 

 in the Aquatic Warbler is an unfailing mark of distinction 

 between this species and the Sedge- Warbler." In the descrip- 

 tion of the rest of the plumage no differentiating points are 

 mentioned. Mr. Witherby and Dr. Ticehurst, writing on the 

 occurrence of Aquatic Warblers since Saunders's book was 

 published (2nd edition), 1899, say: "The Aquatic is much like 

 the Sedge-Warbler in general appearance, but the broad buff 

 line down the centre of the crown distinguishes it at once when 

 seen in close quarters." * Mr. Barrington, writing on the only 

 other Aquatic Warbler obtained in Ireland, says: "The buff 

 stripe along the centre of the head, with a darker stripe at 

 either side, which is separated again from a brighter stripe from 

 the eye, sufficiently distinguishes this bird from its nearest ally 

 the Sedge-Warbler." f Now, while the broad medial buff stripe 

 is markedly conspicuous in the head of the Aquatic Warbler, 

 and normally is not found developed to such an extent in the 



* " On the more Important Addition to our Knowledge of British Birds 

 since 1899." ' British Birds,' vol, i. p. 85. 



\ 'Irish Naturalist,' vol. xii., November, 1903, p. 300. 



