^'"^igif^T Brewster, Notes on the Flight of Gulls. 91 



and accurately adjust and readjust the set of their wings and the 

 equilibrium of their heavy bodies so as to meet in precisely the most 

 effective way, without either loss or gain of headway, each succes- 

 sive gust and interval of comparative calm. With regard to indi- 

 vidual proficiency and endurance in performing arid maintaining 

 such flight little if any differences were noticeable among the one 

 hundred or more Herring Gulls who followed the 'x\rabic' on the 

 afternoon of August 2, 1911. Nor were two Lesser Black-backed 

 Gulls {Larus fuscus) who accompanied them inferior to them in 

 these respects. But two superb Great Black-backed Gulls {Larus 

 marinus) who joined the throng at the height of the gale and kept 

 along with us for half an hour or more just above the level of the 

 upper deck flew, all the while, as most Gulls do on ordinary occa- 

 sions, that is by alternate flapping and sailing, beating their wings 

 vigorously every few seconds. Quite evidently the art of gliding 

 far into the wind on set wings was beyond either their knowledge 

 or their power, else surely they would have resorted to it, with 

 scores of birds close about them practising it. Whenever, as not 

 infrequently happened, the Herring Gulls descended to within 

 ten or fifteen feet of the crests of the waves they, too, seemed 

 unable to advance against the wind without frequent, vigorous 

 wing strokes. At such low levels the gliding flight appeared, 

 indeed, to be never exen attempted by any one of them, a fact 

 doubtless possessing no little significance if only one knew just 

 how to interpret it. 



Before sunset our escort of Gulls became much reduced and 

 before dark all the birds had left us. Thus they did not follow 

 us quite out of sight of the shores of Ireland where, no doubt, 

 many of them had nests with eggs or young. No others of their 

 kind rejoined us the following morning nor were any again seen 

 until we neared the coast of Massachusetts. 



My readers will understand, of course that what I have had to 

 say in the way of attempted explanation of the movement of 

 gliding Gulls represents little more than personal inference and 

 opinion based on field observations made under favorable conditions 

 but extending over only two half days. Hence it should be taken 

 as suggestive rather than assertive. The problem to which it 

 relates is too difficult to be dealt with thus superficially and at the 

 same time effectively. Before attempting seriously to solve the 



