THE SEA-BIRDS. 375 
one of the richest sources of guano. The upper layer of these 
beds is of a greyish brown, and the inner part is the colour of 
iron-rust. The hardness of the guano becomes greater as the 
depth increases. 
The voice of sea-birds is never soft and harmonious, like that 
of many of the songsters of our groves; it is nasal and ringing, 
and often hoarse and lugubrious. Gulls and sea-mews utter sharp 
cries, which are heard above the roar of the tempest. Some ducks 
send forth a piercing clang like a clarion. There are water-fowl 
which, owing to their wide and curved windpipe, are able to imitate 
THE COMMON PENGUIN. 
(Alca torda.) 
exactly the sound of a trumpet. Some seem to cry like little 
children, or to chuckle like old women. The Greeks designated 
the pelican, “ onocrotalé,” or ‘bray of the ass,” because this bird 
seems to imitate that inharmonious noise. Penguins make a 
croaking as melancholy as it is disagreeable. Lesson says, that 
in the Falkland Isles, towards sunset, they utter in chorus a 
loud cry which reverberates to a great distance, and resembles 
the clamour of a tumultuous army. 
A very original observer studied the language of the sea- 
swallow for eight years, and compiled a dictionary on the model of 
Dupont’s “ Dictionary of the Raven.” He has distinguished fifty 
words, expressing, he considers, each of them a distinct idea :— 
‘Tei; la; en avant ;.en arriére; a droite; a.cauche; plus vite; plus 
