350 BRITISH BIRDS. 
Genus ACROCEPHALUS. 
The Reed-Warblers were included by Linnzus in his extensive genus 
Motacilla, and were afterwards removed by Scopoli, along with the other 
Warblers, into his genus Sylvia. The elder Naumann was the first to 
subdivide Scopoli’s genus; and in 1811, in the Supplement to his ‘ Natur- 
geschichte der Land- und Wasser-Végel des nordlichen Deutschlands und 
angranzender Linder,’ p. 199, he founded the genus Acrocephalus for the 
Reed-Warblers, and placed A. turdoides first on his list. This bird, which 
is a fairly representative example of the genus, may therefore be accepted 
as the type. 
The Reed-Warblers are a well-marked group of birds, distinguished by 
the possession of a very minute bastard primary and a moderately rounded 
tail. The bastard primary is so minute that in adult birds it does not 
usually extend as far as the primary-coverts ; but in birds of the year, and 
in one or two species slightly aberrant in this respect, it is usually some- 
what longer, occasionally extending beyond them. ‘The bill is typically 
large, depressed and broad at the base, with moderately developed rictal 
bristles. In two of the species the bill is somewhat aberrant, being as 
slender as in the genus Locustella. These two species are also distinguished 
by a different style of colouring, each feather on the head and back being 
darker in the centre. The existence of two other intermediate species, 
however, makes it advisable not to separate them more than sub- 
generically from the typical Acrocephali, of which they form the Cala- 
modine group. ‘ 
The tail is more rounded than in Hypolais, and much more so than in 
Phylloscopus, but not so much so as in Locustella, the outside tail-feathers 
being longer than the under tail-coverts. The general colour of the 
plumage is a more or less uniform brown, sometimes olive-brown, some- 
times russet-brown, gradually fading, as the plumage becomes abraded, 
into a neutral brown or dust-brown, not inaptly described as museum- 
colour. 
The Reed-Warblers, as their name implies, frequent marshy districts, 
reed-beds, and the dense vegetation on the banks of still waters. They are 
possessed of considerable powers of song. They build well-made open 
nests, sometimes suspended over the water, attached to reeds or twigs, and 
sometimes in the bushes ; and their eggs are from four to six in number. 
Their food is principally insects. 
The breeding-range of these Warblers extends over the whole of the 
Central and Southern Palearctic Region; and one species is found as far 
