COMMON SWIFT. 261 



THE generic characters here inserted show the difference 

 which exists in the structure of the foot and in the wing of 

 the Swift as compared with the same parts in the species 

 of the genus Hirundo, previously described. The great 

 extent of wings, moved as they are by very large and 

 powerful muscles, afford that decided power of flight which 

 all have witnessed ; and the range of the toes, all four of 

 which are turned to the front, assist these birds materially 

 when climbing within the narrow apertures which they 

 select for their nesting-places. 



The Swift comes to this country from Africa, and most 

 probably by the same route as that pursued by the Swallow 

 and the Martin ; it generally appears early in May, and 

 without more variation than is observed in the arrival of 

 the other species of this family ; but the greater part of 

 them leaving us again by the middle of August, their stay 

 here seldom much exceeds three months. Swifts have 

 been found to return to the districts, and even to the nests, 

 they have inhabited during previous seasons, as the follow- 

 ing paragraph will show : " It is a remarkable fact," says 

 Dr. Jenner, " that the Swallow tribe, and probably many 

 other birds, which absent themselves at stated periods, 

 should return annually to the same spot to build their 

 nests. The Swift, which for nine months has some distant 

 region to roam in, was selected for the purpose of an ex- 

 periment to ascertain this with precision. At a farm- 

 house in this neighbourhood, (Berkeley, Gloucestershire,) 

 I procured several Swifts, and by taking off two claws 

 from the foot of twelve, I fixed upon them an indelible 

 mark. The year following their nesting-places were ex- 

 amined in an evening when they had retired to roost, and 

 there I found several of the marked birds. The second 

 and third year a similar search was made, and did not fail 



