MIGRATORY BIRDS. 



9 



addressing her apparently in angry tones : but in general, the woo- 

 ing is agreeable and soon brought to a successful issue, the female 

 thence forward devoting herself to her mate with all possible af- 

 fection and tenderness. 



Nest Building. — As soon as birds have mated, they look out 

 for suitable nesting-places, unless they belong to the class of birds 

 that have regular domiciles, to which they return from year to year. 

 The nests are usually built in the central portion of the district 

 which the birds inhabit, and are different in their architecture and 

 materials. Birds of prey build nests on lofty trees or high 

 rocks ; the running birds generally build on the ground ; others, 

 on the branches, or in the hollows of trees (sometimes excavated 

 by themselves), in the forks of bushes, or on the ground, among 

 mosses or weeds. Aquatic birds make nests on the shore among 

 rushes, weeds, or grass, or in sand-banks. Sometimes they fasten 

 the nest to the rushes and leave it to float on the surface of the 

 water, as do the Gallinules where the water alternately rises and 

 falls. Some sea-birds build nests in rocky caves, or like the Puf- 

 fins, dig out hollows in rocks for that purpose. 



The concealment of the nest seems to be a great object with all 

 birds. Where it is built in open places, it is so constructed as not 

 to be easily observable. Some birds hardly make a nest at all, but 

 lay their eggs on the bare ground, or on the naked surface of a 

 rock. Some only make a small cavity in which to deposit their 

 eggs ; others fill the cavity with some soft and warm material ; and 

 others still, including those that build their nests on trees or form 

 running nests on the ground, construct a sort of trestle-work as a 

 basis for the nest. 



The architecture of nests on trees and shrubs is as varied as are 

 the birds that build them. Some nests are put loosely together ; 

 others are made in a more regular form out of tree branches, woody 

 fibers, etc. ; while other regularly formed nests are neatly lined with 

 fine roots like threads and with hair or feathers. Some nests are 

 roofed or arched over, and the entrance into others is lengthened 

 to a kind of tube through which the birds creep in and out. The 

 weaver-birds knot and sew their nests with long fibers or threads, 

 and use, besides, little twigs and the soft wool-like material of dif- 

 ferent plants. Nuthatches are also adepts in the art of nest build- 

 ing, forming the walls of their nests with loam, which, made into 

 mortar or paste by the saliva of the bird, becomes hard and dura- 

 ble. The principal use of the nest is to serve as a depository for 

 the eggs and a cradle for the young. Some birds, however, build 

 nests for their own amusement or for shelter in winter. To this 

 class belong several kinds of weaver-birds, the Atlas and Collar 

 birds, and Woodpeckers also, which always sleep at night in the 

 hollows of trees, together with the domestic Sparrow, that regu- 

 larly retires at night to a warm and well-lined nest, at least in 

 winter. 



The female bird usually constructs the nest, while her mate 

 brings the materials. But among the weaver-birds the nest is 

 chiefly built by the male. Among other birds, the male acts as a 

 sort of architect or superintendent, watching and directing the fe- 

 male during the progress of the work. The males of polygamous 

 birds take no part in the construction of nests. Male birds gen- 

 erally, during the time of nest-building, entertain their female com- 

 panions with sweet songs, or encourage them with their agreeable 

 chatterings. Some birds' nests are made for a common use ; dif- 

 ferent females lay their eggs in them together, which are often 

 hatched alternately. Other birds build a large nest in common, 

 and divide it into several apartments, each of which is used by a 

 separate family. 



As soon as the female bird begins to lay eggs, the temperature 

 of her body begins to increase, and she soon has the so-called 

 breeding-fever. This causes her to lose the feathers on some parts 

 of her body. The process of hatching the eggs is chiefly per- 

 formed by the female. She usually sits from the afternoon of one 

 day till the forenoon of the next, and is then only relieved by the 



male while she is necessarily absent, searching for food. Some 

 birds, however, divide the labor of incubation, the male and female 

 sitting alternately. The male Ostrich does all the sitting. The 

 eggs, after the bird begins to sit, are turned almost daily, and are 

 always covered with a soft down when both birds are absent. 



Care of the Young. — The parent birds render no assistance 

 to their young to facilitate their coming out of the shell. But as 

 soon as they have effected their entrance into the world, they are 

 cared for by their parents with assiduity and tenderness. At first 

 they are fed with the tenderest food ; then on that which is more 

 substantial, and, as soon as they are able to leave the nest, they are 

 taught to procure their own food and take care of themselves. All 

 birds manifest great love for their offspring. They will protect 

 them from peril and resort to all sorts of tricks to avert danger or 

 turn away an enemy, risking their own lives in defense of their 

 progeny. These, in turn, are in like degree attached to their par- 

 ents, and listen obediently to their every call. 



Migratory Birds. 



Migrations. — As soon as their young can be safely left to 

 themselves, several kinds of birds commence their journeyings to 

 other countries. This journeying, w r hen it occurs regularly every 

 year, at a time certain, and in an appointed direction, is called 

 " passage." But it takes the name of " wandering," when the 

 traveling is the result of necessity, and therefore takes place 

 neither at a certain time nor in a certain direction, ceasing when 

 the cause that produced it is removed. It is also called "strolling" 

 or " rambling," when the journey is confined within narrow limits, 

 and is merely the result of a desire for a change of residence or 

 for the sake of more abundant food. 



Singing-birds make their passages or migrations every fall, and 

 return in the spring. Aquatic birds set out on their passages long 

 before the severely cold weather sets in. A majority of the birds 

 of North America, and of Northern Europe and Northern Asia, 

 migrate in a more or less southern direction ; those in the Eastern 

 hemisphere journeying southwesterly, and those in the Western 

 hemisphere eastwardly, according to the prospect for finding plenty 

 of food and a good winter-harbor. Rivers, valleys, and mountains 

 serve for guidance to migratory birds. Sometimes these birds fly 

 in pairs and sometimes in large flocks. The shy and feeble travel 

 by night, the bold and strong both day and night. Before they 

 set out, they grow restless and wander about, as if prompted to 

 travel by an irresistible impulse. Birds taken from the nest when 

 young, and kept confined in cages, manifest this same restlessness 

 when the migrating season arrives. 



It is a curious fact, that the birds that leave us the latest in the 

 year, are the first to return, and those that leave the earliest, are 

 the last to return. Birds that leave in November, return in Feb- 

 ruary. North American birds travel to the southern parts of the 

 United States or to Central America. Several kinds of European 

 birds winter in the southern part of that continent, and many North 

 African kinds, dwelling between the thirty-seventh and twenty- 

 fourth parallels of north latitude, migrate south to regions within 

 the torrid zone. Other winter-quarters for migratory birds are 

 India, including Siam and South China. Birds in South America 

 take a northern direction to Southern and Middle Brazil ; and South 

 Australian birds fly to the northern part of the island, some of them 

 even to New Guinea and the neighboring islands. 



All birds of passage, before they start, hold regular meetings, 

 remaining in session for several days. They call in all those that 

 pass by, and as soon as the flock has become large enough, the 

 meeting is broken up, and the long flight begins. During the pro- 

 gress of the meeting, regular musters are held ; leaders are chosen, 

 and such birds as are judged incapable of remaining a long time 

 on the wing and of keeping up with their companions are ejected. 



