THE BIRDS 309 



and are British visitors. One of the latest migrants to arrive is 

 Cypselus apus, a fairly large bird, measuring some seven inches 

 in length, sooty black in colour, with a white chin, very long pointed 

 wings and a forked tail. 



The Humming-birds are peculiar to the New World. They are 

 at once the smallest and most beautiful of the class Aves. Some 

 of the smallest species scarcely exceed a big bumble-bee in size, 

 and the wonderful prismatic hues of the plumage of the tiny 

 creatures as they flit about in the sunshine defy description. 

 They dart through the air with the swiftness of an arrow, and 

 hover over the flowers with rapidly vibrating wings, making with 

 them the humming or buzzing sound that has given the birds their 

 common name. These birds are further distinguished by their 

 extremely long, slender bills which, however, vary considerably in 

 different species and the curious long, extensile tongue, which con- 

 sists of a slender double tube separating into two branches which 

 are furnished at the tip with a membranous fringe. The sternum 

 of both swifts and humming-birds is enormously developed ; it is 

 remarkably long in the keel, very deep, and the wing muscles 

 attached to it are particularly powerful, giving to both species of 

 birds their almost untiring powers of flight. 



The last Coraciiforme birds we have room to notice here 

 are the familiar Woodpeckers (Picida) and Wrynecks (lyngince), 

 which are interesting, as in many points of structure they resemble 

 the Passerine birds and so form a connecting link between the 

 two orders. Woodpeckers are distinguished by their large heads 

 and necks (the latter being provided with exceedingly powerful 

 muscles), the strong, wedge-shaped bill, and the stiff and spiny 

 feathers of the tail. 



With a few exceptions Woodpeckers are shy, solitary birds, 

 frequenting wooded districts, where in the springtime their peculiar 

 ringing laugh and the loud drumming sound caused by the ham- 

 mering of the bill on the bark of the trees are commonly heard. 

 Their boring operations are for the most part confined to decaying 

 trees or unsound limbs, with the object of reaching the insects 

 concealed under the bark ; and in this way, by destroying so many 

 insect pests, the Woodpecker is really a very useful bird. The holes 

 made for the reception of the eggs are of larger dimensions than 

 those bored while it is seeking food, and for these sound wood is 



