BIRDS. 



443 



the lark or blackbird. Every now and then a tern dips into the water, 

 and emerges with a little fish in its bill, which it swallows without alight- 

 ing. In the midst of all this bustle and merriment, there comes gliding 

 from afar, with swift and steady motion, a dark and resolute-looking bird, 

 which, as it clears a path for itself among the white terns, seems a mes- 

 senger of death. But a moment ago he was but a dim speck on the hori- 

 zon, or at least some miles away, and now, unthought of, he is in the very 

 midst of them. Nay, he has singled out his victim, and is pursuing it. 



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Fig. 374. — Caspian tern (Sterna tscheyrava). 



The latter, light and agile, attempts to evade the aggressor. It mounts, 

 descends, sweeps aside, glides off in a curve, turns, doubles, and shoots 

 away, screaming incessantly all the while. The sea-hawk follows the 

 frightened bird in all its motions, which its superior agility enables it to 

 do with apparent ease. At length the tern, finding escape hopeless, and 

 perhaps terrified by the imminence of its danger, disgorges part of the 

 contents of its gullet, probably with the view of lightening itself. The 

 pursuer, with all his seeming ferocity, had no designs upon the life of the 



