240 THE BIRDS OF N0ETHA3IPT0NSHIBE 



of Europe which we have visited during the summer 

 months, and before we had visited Gibraltar, were 

 assured that this species was to be found there during 

 the winter, but these supposed Sand-Martins turned 

 out to be the Crag- or Rock-Martins (Ilirundo rii- 

 pestris), a species which is common in many parts of 

 Europe, and only migrates locally from the interior to 

 the coast during the winter months. Many instances 

 are on record of the Sand-Martin nesting in holes of 

 walls ; and we can personally vouch for the accuracy 

 of the case discovered by Messrs. E. Bidwell and 

 H. M. Upcher, as quoted in the fourth edition of 

 Yarrell's ' British Birds,' of these birds selecting 

 heaps of sawdust as their nesting-place. 



104. SWIFT. 



Cypselus apiis. 



In our immediate neighbourhood we may call the 

 Swift a comparatively rare bird, for, although a few 

 pairs nest in the towers or steeples of some few of 

 the numerous churches within a few miles of us, we 

 have no recollection of ever having seen more than 

 three or four of these birds together hawking over 

 the river during our fishing-expeditions in July. 

 There is no mistaking the present species for any 

 other, its ceaseless activity on wdng, the astounding 

 rapidity of its flight, its colour, and its shrill shriek 

 at once distinguish the Swift from any other British 

 bird. We are not able to give anything like an 

 accurate average date for the first appearance of the 

 Swift in North Northamptonshire ; but it seldom 

 appears before the first week in May, and is about 



