310 THE BIRDS OF HELIGOLAND 



125. Aquatic Warbler [BINSEN-KOHRSANGER]. 

 SYLVIA AQUATICA, Latham. 1 



Heligolaudish : Straked Siillen-Kroper - Striped Eeed Warbler. 



Sylvia aquatica. Naumann, iii. p. 686. 



Aquatic Warbler. Dresser, ii. p. 591. 



Bee-fin aquatic. Teimninck, Manuel, i. 188, iii. p. 114. 



I first found this handsome bird in 1847, since which time it has 

 been met with and shot in Heligoland almost every year, though, 

 for the most part, in solitary cases. In 1855, however, the bird 

 occurred pretty frequently, and in the following year in extraordi- 

 narily large numbers. 



The distribution of this species as a breeding bird is scarcely 

 as yet ascertained to its full extent ; at any rate, the conditions 

 under which it makes its appearance here are not in harmony with 

 the statements made in regard to its breeding area. The nesting 

 stations cited for this species are Algiers, Italy, France, Germany 

 especially the west Holland, and in solitary instances in Sleswick- 

 Holstein and Denmark. 



From the frequent, and in one case at least, very numerous 

 appearances of young birds during the autumn migration, and their 

 complete absence in the spring I have only once obtained a bird 

 in April we may with safety conclude that, so far as Heligoland is 

 concerned, the species is a far Eastern one. This conclusion received 

 considerable support from the fact that, on the 13th of August 1856, 

 when these birds appeared here in unprecedented numbers, another 

 species from Eastern Asia was taken viz. Sylvia certhiola. Again, 

 during September 1876, when several individuals of S. aquatica 

 were seen and shot here, a very strong migration of eastern species 

 took place. Thus, on the 4th, 6th, and 15th, and daily from the 

 last date to the end of the month, Antkus richardi occurred in 

 numbers from five to twenty; on the 22nd, two examples of Antkus 

 cervinus and one of Motacilla citreola ; on the 25th, two examples 

 of S. aquatica were shot, and one example each day of S. superci- 

 liosa on the 26th, 29th, and 30th. Similar occurrences were 

 repeated in the course of October. 



The hundreds and more of these birds that arrived here on the 

 13th of August, above referred to, could not have corne from Sles- 

 wick-Holstein or Denmark ; for, in the first place, they are far too rare 

 in the latter countries for such a possibility, and secondly because, 

 from reasons hitherto unexplained, no migration at all of species 



1 Acrocephalus aquaticus (Gmel. ). 



