402 SAND MARTIN. 



them to protrude their heads, and they will thus 

 suspiciously survey the cause of their alarm until 

 it is either removed or forces them to leave the 

 nests. The nest is formed of clay agglutinated 

 together, and is of a circular form, suited to the 

 shape of the rock or building which supports it, 

 but completely closed round, except a small hole 

 at the upper side for access. The inside is first 

 lined with dried grasses, and within with a warm 

 coating of feathers. The eggs are of a delicate 

 white with reddish brown spots. 



This Swallow is generally distributed over 

 mkldle and southern Europe, but we are igno- 

 rant of its range elsewhere. Ternminck states 

 that it does not extend beyond the tropics. The 

 American species, H. bicolor, for some time con- 

 founded with it, is distinct, the bird of Europe 

 not being known in the New World. 



The upper parts, with the exception of the 

 rump, glossy bluish black, with a steel blue 

 lustre ; the wings and tail, the latter slightly 

 forked, brownish black glossed with bluish ; the 

 rump pure white, appearing most conspicuously 

 during flight ; under parts of the same pure 

 colour. Difference between the sexes is very 

 trifling. 



THE SAND MARTIN, HIRUNDO RIPARIA, LINN. 



H. riparia of authors. Cotile riparia, Boje. 



Sand or Water Swallow or Martin of British 

 authors. This Swallow, with a few others, has 



