DUCKS, GEESE, AND SWANS. 237 
Swan, two other species are British, in the sense of 
visiting our area to winter. 
HOOPER SWAN. 
This fine bird, the Cygnus musicus of Bechstein, 
as well as of most modern ornithologists, is a 
tolerably common winter visitor to the British 
Islands, frequenting inland waters as well as the 
coasts. It is of more frequent occurrence in 
Scotland, than in England or Ireland. The 
Hooper—sometimes rendered Whooper—or Whist- 
ling Swan, both names being derived from the 
bird’s notes, may be distinguished from its two 
British allies by having the basal portion of the bill 
extending below the nostrils, yellow. Like many 
other species that visit us during winter from the 
high north, its numbers vary a good deal in 
different years, according to the mildness or severity 
of the winter in regions lying directly north or 
north-east of our area. In periods of long con- 
tinued frost, great numbers of this Swan collect off 
certain parts of our coasts, driven seawards from 
inland waters. This Swan is rarely seen in British 
waters before October or November, whilst in some 
years it does not make its appearance in certain 
localities before mid-winter. Its spring migration 
northwards lasts through April and May. Whilst 
on passage the flocks of this species form into some 
rectilinear figure and fly at vast heights. Gdatke 
remarks, that at Heligoland this Swan is seen most 
