68 BRITISH BIRDS. 



Common throughout British Isles from the end of April 

 to mid-October, except in North Scotland, where it is 

 rather scarce. Nest, placed beneath the eaves of buildings, 

 under bridges, or against the face of a cliff ; never open at 

 the top like a swallow's, an entrance hole being made in 

 one side ; constructed of mud pellets, and lined with grass 

 and feathers ; usually much infested with the bird's 

 parasites. Eggs : 4 or 5; immaculate white; size, '80 by '52. 

 Two or three broods are produced. Food : winged insects. 



GENUS XXXIV. COTILE, F. Boie (18B2). 

 Differs little from Chelidon except in having feet naked, 

 save for a few feathers above the hind toe. 



83. Cotile riparia (Linn). SAND-MARTIN. 



Hab. Circumpolar, breeding in Europe northward to 

 lat. 70 in Norway. Migrating southward in winter. 



Male : above mouse-brown, wings and tail blackish ; 

 below white, excepting a pale brown band across breast ; 

 bill black ; tarsi reddish-brown. Length nearly 4*75 ; 

 tail moderate, distinctly forked. Female differs little. 

 Young: darker below, and feathers of upper parts are 

 tipped with buffish-white. 



Locally common throughout British Isles from end of 

 March to late in September ; Mr. Ussher says that in 

 Ireland it breeds more commonly than the House-Martin. 

 Breeds in colonies in sandstone cliffs, railway cuttings, 

 etc. ; nesting hole is bored by the bird and penetrates 

 about two feet with a slight ascension ; nest consists of a 

 little grass and feathers. Eggs : 4 to 6 ; pure white ; size 

 72 by '50. Two broods are produced ; the birds are 

 rather bold and will pursue birds of other species which 

 approach their nests, uttering a low and rather harsh 

 alarm-note ; male has also a weak twittering song. 



