234 HIRUNDINID-E. 



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 witli the same parts in the three 

 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 following 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 experiment 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 examined 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 to produce some of those which were marked. I 

 now ceased to make an annual search, but at the expiration 



