(510 CYPSELUS. SWIFT. 



of a quadruped, than the feet of any other bird ; the tarsus ex- 

 tremely short, feathered anteriorly, bare behind. The pollex 

 or inner toe smallest, the third largest, the second next ; the 

 first too not directed backwards, but forwards and inwards, so 

 that it cannot be put in opposition to the rest, collectively, al- 

 though it may to the fourth or outer. Another very remark- 

 able circumstance is that the toes have all the same number of 

 articulations, namely two, and are very short ; they have a 

 few scutella above, and are obscurely papillate beneath. Claws 

 large, strong, tapering, curved, very acute, moderately com- 

 pressed, convex above, flattish beneath. 



Plumage soft, rather blended, glossy, the feathers oblong, 

 with a rather tufty moderate plumule. There are no bristle- 

 feathers at the base of the bill. Wings extremely long, nar- 

 row, and pointed ; the quills and coverts with exceedingly 

 strong, elastic shafts ; the quills eighteen, the secondaries very 

 short and rounded, the primaries ten, tapering to a rounded 

 point, the outer a little incurvate towards the end, so as to ren- 

 der the wing falciform. Tail long, but much exceeded by the 

 wings, deeply forked, of ten tapering feathers having strong 

 shafts, the outer slightly recurved. 



The Swifts differ from the Swallows chiefly in having their 

 feet stronger, although shorter, and their toes different in form 

 and disposition, with stronger claws all so directed that the 

 bird can cling very securely even to a perpendicular surface. 

 Owing to the extreme shortness of their feet, they are unable 

 to walk, unless with a most constrained and hobbling gait, 

 with the aid of their wings, the extreme length of which com- 

 bined with the form of the feet, prevent them from rising 

 from a flat horizontal surface, so that they never settle on the 

 ground, but alight only on such places as present a brink or de- 

 clivity from the edge of which they can launch forth in a curve. 

 Their flight is extremely rapid, and on wing they perform the 

 most aburpt turns and the most varied evolutions, with the 

 greatest ease. They nestle in holes in buildings, or in crevices 

 of rocks, forming their nest of materials gathered on wing. 



Only two species occur in Europe, of which one is generally 

 distributed in Britain. Two or three individuals of the other 

 have been killed in England. 



