160 BRITISH SEA BIRDS. 
Caithness; elsewhere it is only known as a winter 
visitor. In many of its habits it closely resembles 
the preceding species. It is exclusively aquatic, 
only seeking the land during the breeding season, 
but is, perhaps, not quite so oceanic as that bird 
in the winter, when it not unfrequently haunts 
inland waters. It dives with equal skill, flies with 
the same powerful rapidity, and utters during the 
nesting season very similar unearthly cries. Fish 
form the chief food of this Diver, but it is said 
also to capture frogs. Most of the examples of 
this Diver that are seen close in-shore (on our 
eastern and southern coasts principally) during 
winter are immature, the older birds as a rule 
keeping further out to sea. The Black-throated 
Diver indulges in the same peculiar habit of 
gradually sinking its body in the sea when 
alarmed, and will frequently seek to escape pursuit 
by diving outright, and swimming under water 
for a considerable distance. 
The Black-throated Divers that breed with us, 
retire to their inland haunts in May. Its favourite 
nesting places are on islands in moorland lochs, 
pools, and tarns. It displays few social tendencies 
at this season, although several pairs not un- 
frequently nest within a comparatively small area 
of exceptionally suitable country, each, nevertheless, 
keeping to its own particular haunt. This Diver 
may also pair for life, seeing that it evinces con- 
siderable attachment to certain favourite nesting 
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