Indeed, we shall now soon begin to make progress in nest building, for the next group of birds, which _dart_ at their food with wide-gaping mouth and seize it on the wing, have among them many clever little architects. It is true our English kingfisher builds in holes on the river bank, lining her nest with fishes’ bones, and the Nightjar (wrongly called the goatsucker), with her wide-gaping mouth, lays her egg on the ground. But both these are lowly Darters, for the kingfisher sits on a bough close above the water, and pounces down upon the fish or water-insects; and the lonely nightjar, with her strange wailing cry, flits among the bushes in the twilight, or often even creeps after her prey. Neither of these birds can compare in flight with the Swifts, as they dart upon the wing from some high pinnacle to collect a mouthful of insects, and come back to eat them, nor to the lovely little Humming Birds of America, which poise themselves so deftly on the wing, while their slender bill searches the long-tubed flowers for insects or seizes these as they pass. These living jewels of nature build beautiful and delicate nests of leaves and grass and spiders’ webs interwoven like fairy cradles; while the swift makes a far stronger home of hair and feathers, grass and moss, glueing them together with saliva[105] from his mouth, and fastening them under the eaves or on the top of some tall waterspout. It is easy to see why the swift chooses such lofty spots, for his slender weak toes are ill-fitted for standing on the ground, and he rises with great difficulty when once he has alighted there, but from a height he can drop easily on to the wing, and skim the air for his food. Now the swift, which visits us only in summer to build his nest, when insects are plentiful, and spends the rest of his time in Africa, is a type of a whole army of birds, lovely, bright, and gay, with short weak feet, long wings, and a gaping mouth surrounded by bristly hairs, which swarm in hot countries where insects are to be found all the year round. Among these are the beautiful little Bee-eaters and Rollers of the East and Africa, which revel in insect food, and sometimes visit us in the summer, coming over to the south of Spain, or even, in the case of the rollers, as far north as Sweden; while in South America the dull-coloured Puff-birds, the brilliant Jacamars with their metallic-looking feathers, the delicate little Todies, the bright green Motmots, and the lovely Humming-birds, swarm in countless numbers, hiding among the dense foliage, or darting in the bright sunshine after bee or butterfly, or other unwary insects. * * * * *