1110 Birds. 



and either one of the parent birds, or one of its numerous young 

 which has been bred there, returns to the same locality for many suc- 

 cessive years. 



Common Swift, Cypselus Apus. This bird is called by us swift, 

 — par excellence — of its great strength and surprising rapidity of flight, 

 in truth, it may be said to live on the wing. It is hereabouts much less 

 abundant than the other Hirundinidae. Its congener, the alpine swift 

 [Cypselus alpinus), has been of late years observed in England, al- 

 though it has never yet been known to reach this north latitude. I 

 am perfectly acquainted with it, as having seen it in great numbers 

 among the alpine districts of Europe, especially of Switzerland, and 

 the rocky shores of the Adriatic and of the Mediterranean. In its 

 flight, it is even stronger and more vigorous than the common swift : 

 it utters a similar scream when flying after and chasing its companions ; 

 and in its other habits it extremely resembles that bird. Its pure 

 white belly well marks it, while on the wing. The viscid saliva of 

 the swifts, as also of the goatsuckers, enables them to hold in their 

 mouths the insects caught whilst flying. The foot of the swift is singu- 

 lar, having all four toes placed before, with the claws thick and strong. 



Nightjar, or Goatsucker, Caprimulgus Europaus. Not very 

 unfrequent in the solitary and woody places in this vicinity, where it 

 nidificates in the summer. Pennant was mistaken in his statement, 

 that this migratory bird " disappears in the northern parts of our 

 island the latter end of August " (p. 567, vol. i. edit. 1812), for it con- 

 tinues with us till October. When its mouth is wide open it appears 

 exceedingly ugly. The size of its gape has much similitude to that 

 of the bats, whilst the strong bristles placed on the sides of the upper 

 mandible are likewise rather analogous to the teeth of those animals ; 

 and they assist, like them, in securing its prey. It is worth noticing, 

 that the largeness of the mouth in the goatsuckers and bats, is pecu- 

 liarly necessary in seizing insects on the wing, during the dusk of the 

 evening, and is an admirable adaptation of structure to its use. So 

 also, the large ears in these birds correspond with those of the bats 

 and owls. Hence, the acute sense of hearing in all these nocturnal 

 or crepuscular animals, is most probably a mean of directing them to 

 their prey, and of guiding them in their flight. From a supposed 

 likeness to the swallow, some authors have changed its generic name 

 to Nyctichelidon, night-swallow ; but which I hold to be needless. 

 The foot of the goatsucker resembles that of the swallow, only with 

 its thumb, or hind-toe reversible, or brought to the side. Also the 



