TREE SWALLOW 393 



At the end of each stroke, the tips of the wings are brought back- 

 ward until the primaries are nearly parallel with the long axis of 

 the body. A robin also shows this peculiarity but to a less degree. 

 The bird swings to the right and left, to be sure, but there are periods 

 of straight flying or sailing, and always there is the impression of a 

 steady drive through the air, with a good deal of power for so small 

 a bird. 



The tree swallow, compared with the barn swallow, appears to be 

 less steady in the air, although doubtless it possesses complete mas- 

 tery over it. There is a suggestion of flickering in its flight, due 

 perhaps to the quicker, less forceful motions of its wnngs. Flying 

 at a distance, it sometimes resembles a starling — another quick-mov- 

 ing bird — but most characteristic is the habit of hunching up its back, 

 or seeming to do so, and lowering its wing tips as it sails, like an 

 inverted saucer in the sky. Francis H. Allen (MS.) speaks of their 

 flight as "largely a succession of reaches and runs with periods be- 

 tween them when the bird seems to hang in stays for a while — to 

 speak in nautical terms." 



In the air the tree swallow resembles somewhat the purple martin, 

 the similarity being due probably to the triangular shape of the 

 wing in both birds — a triangle with a sharp apex and a fairly broad 

 base. The bank swallow is readily distinguished from the tree 

 swallow by its habit of hugging its wings close to the side of its 

 body when it sails and by the suggestion of soft fluttering in the 

 motion of its wings. 



Tree swallows do not linger long about their nests once the young 

 are on the wing. Both the young and the adult birds apparently re- 

 tire to broader feeding grounds — the meadows bordering river val- 

 leys or marshes near the seacoast — where, gathering in increasing 

 numbers, they form the nucleus of the autumn flocking. 



Often because of a scarcity of nesting-holes or boxes, but some- 

 times because of a preference for a certain site, tree swallows come 

 into conflict with other species of hole-nesting birds as well as indi- 

 viduals of their own species. F. Seymour Hersey (1933) relates a 

 remarkable example of such an encounter. A pair of bluebirds were 

 breeding in a box in his garden, and the female was incubating a 

 set of eggs. He continues the story : 



Then, one day, a pair of Tree Swallows arrived and decided they wanted 

 that particular box. I hurriedly put up boxes No. 2 and No. 3 but the Swal- 

 lows paid no attention to these new nests and after a day of constant bully- 

 ing the Bluebirds surrendered their nest and eggs and retired to box No. 2. 

 The Swallows remodelled the Bluebird's nest, incidentally disposing of the 

 eggs in some way, and the Bluebirds started another nest in box No. 2. For 

 awhile peace and quiet reigned and both pairs of birds had young a few days 

 old when a second pair of Swallows put in an appearance. Once more there 



