350 
BIRD-LIFE. 
confused swarming, whirring, screaming mass. No one 
who has not experienced it himself can form any 
estimate of the appearance of this teeming, living crowd. 
The way in which the nests are crowded together 
is most singular; in places, indeed, where there is 
plenty of room the sitting birds are often so close to one 
another as to touch, and they would be in each other’s 
way did not every bird sit with its head towards the sea. 
Even when taking the greatest care the egg-collectors 
cannot help crushing some, because in many places the 
nests are not the breadth of a foot apart. It is a beautiful 
sight to behold at one glance so many nests and eggs 
collected at one spot.” 
The most remarkable thing is that each individual 
bird should know its own nest amongst so many, and 
amid such a turmoil. It is possible that the birds are 
not particular as to what nest they sit on, and that each 
Tern occupies any nest that may be vacant, yet the 
results of observation seem to contradict this supposition; 
thus we may assume that each bird knows its own nest. 
As colonists, next to the Terns come the Gulls, the 
Eavens of the sea. Most of the islands of the North, 
whose positions render them adapted for the purpose, are 
used as breeding-places by one species or another; 
nearer the Pole they breed in company with other arctic 
birds. On the Continent, even in Germany in some 
places, the Black-headed Gull (Lams ridibundus ) often 
nests in extraordinary numbers. “ A single pair,” says 
Naumann, “ is never found breeding alone, and a colony 
of from six to ten pairs is rare; they are far oftener 
found by hundreds and thousands, which form a single 
assemblage, nesting together, like the Terns, within a 
very small area. There are flocks which resemble a 
