THE SWALLOWS AGAIN. 51 



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as it sounds to say so, the swallows and the humming- 

 birds are indeed first cousins to one another, though so 

 very different in outward shape and plumage. Indeed, 

 nowhere else are appearances more deceitful. The hum- 

 ming-birds are not at all rekted to the sun-birds of India 

 and Africa, which are so like them as to be colloquially 

 called by their name ; while they are closely related to 

 the very unlike swallows, being, in fact, American swal- 

 lows which have never taken to migrating very far north, 

 and have accordingly adapted themselves instead to a 

 continuous tropical or sub-tropical existence. 



Prince Lucien Bonaparte was the first to show that 

 the humming-birds were really most nearly allied to our 

 dingy northern swifts. Of all the swallow family, the 

 swifts are the most ceaselessly active and possess the 

 widest relative stretch of wing. Though a full-grown 

 bird usually weighs scarcely one ounce, it measures 

 eighteen inches from tip to tip of the pinions. No one 

 ever saw a swift perching on a tree or hopping about the 

 ground ; except when asleep, it is almost ceaselessly 

 upon the wing. It catches its food flying ; it drinks as 

 it skims the surface of the water ; it picks up the mate- 

 rials for its nest while sweeping among the meadows 

 close to the ground. Now, if you transfer some of these 

 active, restless, ^insect-catching swifts to the tropics, 

 what will be the natural result ? A large proportion of 

 tropical insects find their food in the large bells or deep 

 tubes of the brilliant equatorial flowers. So the swifts 

 would naturally take to flitting about in the neighbor- 

 hood of these blossoms and poising themselves on their 

 powerful wings just in front of their corollas. Those of 

 them which took permanently to such a mode of life 

 would soon adapt their external structure to the new 

 conditions with which they had grown familiar. Tropi- 



