214 On the Ornithology of Wilts \_Hirundinidce]. 



only do we welcome them as heralds of spring and harbingers of 



sunshine ; in addition to this, all their movements are so graceful, 



they are so essentially birds of the air, seldom touching the earth, 



but careering all daj'- long under the bright blue sky and through. 



the lofty pathways of the air, that they engage our particular 



admiration and interest : if we stand still to watch one of these 



birds in its course, see with what arrowy speed it darts over our 



gardens, sweeps round our houses or skims over the pool : now it 



will wheel and sport high up in the air, hurrying here and there 



on the lightest wing in the gladness of its heart ; anon it will float 



without effort in the vast expanse, as much at home and at ease as 



other birds when perched on a tree or motionless on the ground : 



and for this aerial life how admirably their structure is adapted : 



observe the shape of the body, how full the forepart, how gradually 



tapering towards the tail, which is exactly the principle on which 



the fastest sailing ships are constructed : then see the plumage, 



how firmly compacted, how little liable to be ruffled by the breezes 



in a long and rapid flight ; mark the wings stretching out like 



oars of vast length, and moved by muscles of extraordinary power : 



note the long forked tail, supplying a never failing rudder to guide 



the bird through those numerous windings in which it delights. 



Other characteristics of this family, in addition to those belonging 



to the whole tribe, are, very short beak, very broad at the base 



and slightly bent ; head quite flat, and neck scarcely visible : their 



note is rather a continued twitter than a song, though some of the 



species will scream in a high and wild key, and others have a not 



unpleasing though monotonous and very gentle melodious warble. 



All the four species of this family with which we are acquainted 



are summer visitants, leaving us in the autumn : it used to be 



asserted by older naturalists, before the habits of birds had been so 



closely observed, as of later years, that the Hinindines did not leave 



this country in the winter, but retired to caves or holes, and there 



remained dormant, like the bats and dormice : others maintained 



the wilder theory that they plunged into the beds of rivers and 



lakes, and there amidst the sedge and mud and reeds at the bottom, 



slumbered away the dreary months of ice and snow, till the genial 



