THE EARLIEST KNOWN WATERBIRDS
CHAPTER VI.
THE FEATHERED CONQUERORS OF THE AIR.
Part I.—Their Wanderings over Sea and Marsh, Desert and Plain.
It is a warm sunny day in early spring, one of those few bright days which sometimes burst upon us in April, just after the swallows have come back to us, searching out their old nooks under the eaves, or their old corners in the chimneys, to build their new nests. There they are, clinging with their sharp claws to the edge of the cottage thatch, while the impudent little sparrow, which has remained hopping about all the winter long, chirrups at them from a neighbouring apple-tree. Upon the grass-plot near a blackbird is pecking at a worm, and from the wood beyond a thrush trills out his clear and mellow song, accompanied from time to time by the distant cry of the cuckoo calling to his mate. For it is the love-time of the birds; and as we watch them flying merrily hither and thither in the bright sunshine, we ask ourselves whether we must not have made a great leap on leaving the cold-blooded snakes and tortoises, since now we find ourselves among such merry, warm-hearted, passionate little beings, with their beautiful feathery plumage, their light rapid flight, their love for each other, their skill in nest-building, and their patient care for their little ones.
And, indeed, we have come into quite a new life, for now we are going to wander among the conquerors of the air, who have learned to rise far beyond our solid ground, and to soar, like the lark, into the clouds, or, like the eagle, to sail over the topmost crags of the mountains, there to build his solitary eyrie.
Even the little sparrow, which flits about by the roadside, can laugh at us with his impudent little chirp, as he flies up out of reach to the topmost branch of a tree. And yet a glance at his skeleton will show us that he has the same framework as a reptile, only it is altered to suit his mode of life.
Fig. 32.
The Sparrow.
With wings raised, as in the skeleton on next page.
True, his breastbone (b, [Fig. 33]) is deep and thin instead of flat, and those joints of his backbone which lie between his neck and tail are soldered firmly together, more like those of the tortoise, and he stands only upon two feet. Yet this last difference is merely apparent, for if you look at the bones of his wings you will find that they are, bone for bone, the same as those in the front legs of a lizard, only they have been drawn backwards and upwards so as to work in the air.