The passerine order.—The families of the birds hitherto considered in this chapter, with the flycatchers, wrens, chats, tits, finches, linnets, starlings, etc., are further grouped together to form what is called an order. The order which consists of these families derives its name passerine from the sparrow[25] (Fig. 208), perhaps the commonest of the birds included in it. It is probably in [Pg 321] this order that bird structure attains its most perfect development. Again, the birds of the crow family are generally considered to stand at the head of the order; if this view is correct, rooks must be regarded as occupying, among birds, a position which roughly corresponds to man’s place in the class of mammals. Passerine birds are nearly all singers, and their toes are generally adapted for perching. They feed upon insects, seeds (especially the seeds of grasses), and soft fruit. Their beaks vary in form according to the nature of the food upon which they most depend, as is well shown by the soft, widely opening bills of the swallows, the strong but slender beaks of the thrushes, larks, and crows, and the short, hard beaks of such seed-eaters as the canary, sparrow, and other finches. Birds which are exclusively, or almost exclusively, insectivorous are compelled to migrate to warmer countries to obtain food during the winter. The eggs of passerine birds are usually coloured or spotted, and the young birds are hatched in a helpless and almost naked condition, being carefully tended and fed by both parents until they are able to fend for themselves. A few familiar birds of other orders will now be briefly considered. Fig. 208.—House Sparrows. (× ⅕.) Fig. 209.—The Swift. (× ⅙.) 57. THE SWIFT AND THE CUCKOO. 1. The swift.—Distinguish the swift from the swallow by its larger size, its sooty black colour (except for the dull white of the throat), and its long, bowed wings. In what respect does the swift [Pg 322] resemble the swallow? Watch for the appearance of swifts about the end of April. Do the birds arrive singly, in pairs, or in flocks? Notice the rapid turns and twists of the flying bird. Does it as a rule fly near the ground, or at somewhat great heights? Have you ever noticed the bird perching, or settling on the ground? Have you seen it clinging to walls with its feet? Were these the walls of houses or barns, or of high towers? What actions would lead you to suppose that the nests are built in high towers? Are more swifts to be seen in the evening, or during the day? Can you explain this? Watch during the first half of August, and make a note of the day on which swifts were last seen.