254 HABITS OF BIRDS. 



an incessant vociferous call, till a response is re- 

 turned either from some other straggler, or from the 

 colony to which it belongs. The necessity of such 

 a habit as this is still more obvious in the case of those 

 birds which migrate together at night. " Aquatic 

 and gregarious birds/* says White, " especially the 

 nocturnal, that shift their quarters in the dark, are very 

 noisy arid loquacious; as cranes, wild-geese, wild- 

 ducks, and the like ; their perpetual clamour prevents 

 them from dispersing and losing their companions*; 1 ' 

 and accordingly, when residing near the sea or a 

 large river, we have often heard the scream of these 

 night-fliers " startle the dull ear of night." 



There appears, however, to be a decided and well- 

 understood distinction between the call of such 

 stragglers as we have just alluded to, and the 

 gathering-cry when an individual has discovered 

 abundance of food. A sea-mew, or what is more 

 common, a pair of sea-mews, may thus be seen far 

 inland, whither they have probably been driven by 

 blowing weather, coursing about high in the air, 

 sometimes flying in one direction and sometimes 

 tacking about, and all the while uttering at intervals 

 a peculiar call-note ; but even should this occur near 

 the beach, no other sea-mew would think of corning 

 at the signal. But, on the other hand, the note of 

 intimation proceeding from an individual who has 

 discovered a good fishing-station over a sand-bank, 

 is so well understood and so quickly obeyed, that we 

 have repeatedly seen some hundreds of birds hurry 

 to the place in a few minutes, though none were 

 previously observable. 



There are instances, however, of birds thus calling 

 when on the wing, which it does not seem so na- 

 tural to account for on either of these suppositions. 



* Letter 85, 



