402 GENERAL HABITS AND TEAITS OF SWALLOWS 



The flight of Swallows might be inferred from inspection of 

 the perfected wing-structure, not only as to the lengths to 

 which the act can be sustained without fatigue or injury, but 

 to the peculiar ease, grace, and buoyancy of the aerial evolu- 

 tions so characteristic of Swallows. The birds of no other 

 group of Passeres fly quite like Swallows, but the Swifts 

 (Oypselidce) are uearly identical with Swallows in this respect, 

 and so are the Terns, or Sterninw, which, indeed, are com- 

 monly called " Sea Swallows " from this very circumstance. 

 The Hummingbirds have wings constructed on much the same 

 plan as those of Swallows, and are among the few birds, if 

 they be not the only ones, that surpass Swallows in volatorial 

 exploits. The type of the wing is quite dift'erent from that fur- 

 nished by the great ocean wanderers like the Procellariidce, or 

 Petrels, the flight of which is practically limitless in duration. 

 The wing of such birds — especially of the Albatrosses — isinordi- 

 nately lengthened in all its segments — the upper arm and fore- 

 arm as well as in the pinion or hand ; a conformation which 

 results in long, strong, measured wing-beats, as the end of the 

 wing traverses the arc of too large a circle to move with great 

 celerity. The upper segment of the Swallows' wing, on the 

 contrary, is shortened, the development of wing being in- 

 creased in the terminal segment, or pinion, and the large 

 feathers it bears. Such a wing is more deftly handled, and 

 wonderful power of arresting or directing as well as of accelera- 

 ting the bird's course, is assured by this means. The most 

 graceful flyers among the Swallows are the lashing-tailed 

 species of Rirundo proper, like the Barn Swallow, which glides, 

 soars, and sweeps with extraordinary facility, and instantane- 

 ously arrests or diverts its flight at a touch of the guiding 

 helm. The motion of the Swallow skimming the ground, and 

 " quartering" in zigzag after its prey, has been aptly compared 

 to the coursing of the greyhound. No one who has attentively 

 observed the flight of Swallows can have failed to notice tlieir 

 peculiar " towering", when they rise abruptly with few vigor- 

 ous strokes, and seem to hang suspended for a moment, before 

 falling with great velocity through the beautiful curve of the 

 cycloid — with half-gathered wings, and at such little loss of 

 impetus by friction that they avail themselves of this peculiar 

 line to rise nearly to their former level without muscular 

 effort. Sometimes their course is as straight as an arrow's, 

 and only less swift — sometimes they hover and flutter at seem- 



