OF THE BRITISH ISLANDS. 319 



leaves — but water insects and mollusks are also eaten. The note 

 of the Hooper once heard can never be forgotten or confused 

 with that of any other British species. It is a short, loud, clear, 

 far-sounding trumpet-blast, uttered several times in succession, 

 and when mellowed by distance sounds far from unpleasant, but 

 at close quarters is ear-splitting and discordant. Nothing in bird 

 life to my mind sounds so inspiring as the distant yet clear calls 

 of migrating Swans, one to the other, as they cross the night sky. 



Nidification. — The chief breeding grounds of the Hooper 

 are beyond the Arctic Circle on the islands in the deltas of the 

 great rivers that flow into the northern seas, or near the big 

 lakes of the tundras, or the creeks that run some distance inland 

 from the parent stream. The birds pair for life. The nest is 

 usually placed on an island well covered with willow-trees and 

 other dense scrub, or at others amongst the tall rank grass and 

 reeds that fringe the pool. It is a huge pile of coarse grass, 

 sedge, and other herbage built upon the ground, and probably 

 carried to such a height in anticipation of any sudden rise in the 

 water near by. As incubation proceeds it often increases in 

 bulk, the birds adding materials from time to time. In Northern 

 Russia from two to four eggs formed a clutch ; in Iceland five 

 is frequently found ; and old females are said occasionally to 

 lay as many as seven. The eggs are laid towards the end of 

 May in some districts, a fortnight later in others. They are 

 creamy white in colour, rough in texture, and nearly oval in shape. 

 They measure on an average 4*5 inches in length by 2 '8 inches 

 in breadth. Incubation lasts from five to six weeks, and 

 according to Dr. Palm6n the young mature slowly. Only one 

 brood is reared in the year. 



Diagnostic Characters. — Cygmcs, with the tail short and 

 rounded, and with the lores and the basal portion of the bill 

 extending below the nostrils yellow, remainder black. Length, 

 60 inches. 



