BREEDING COLONIES. 
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tlie young birds by the Marsh Harriers, Black Kites, and 
Goshawks even, which breed in the neighbourhood.” 
In the breeding-places of the North the assemblage of 
birds, in the season, is far larger than those on the 
Danube. Most Sea-fowl are sociable; and on this account 
flock together in myriads at nesting time. On the southern 
islands of the North Sea, and still more so on those near 
the coast of Jutland, the most wonderful colonies of 
Gulls and Terns may be seen every spring. Naumann 
relates the following, gathered from his own personal 
observation:— 
“ The Sandwich Tern (Sterna cantiaca ) breeds in flocks 
on all the islands of the North Sea, and in some places 
crowded together beyond belief. A colony of a hundred 
pairs is very rarely seen; they always amount to 
thousands, aye, hundreds of thousands, and occupy 
comparatively a very small area, forming a single 
community. Such a swarm as we describe is not spread 
over several different islands, nor even the whole of one, 
but over only a circumscribed space. Thus, on the little 
island of Norderoog an innumerable flock of Sandwich 
Terns only make use of a very narrow strip of beach 
running along the northern and eastern shore, upon 
which the entire colony is crowded together, both birds and 
nests being placed in dense rows. If an intruder steps 
among them they encircle him in such numbers that the 
mass of fluttering forms fairly darkens the light of day, 
and their screaming quite bewilders him. While, with 
downcast eyes, he treads carefully to avoid breaking 
the eggs, the birds become so bold and dash so close that 
they not unfrequently strike his hat or head with their 
pinions, besides soiling him with their excreta. The 
most vivid description will fail to give any idea of the 
