400 BRITISH BiKUS. 



December. The nest, of mud, is placed under the eaves of 

 houses, walls, and rocks ; the nest is cup-shaped, with a hole at 

 the top or side. They, like the swallow, feed entirely on 

 insects. Sparrows wage war against them, and often drive 

 numhers away from their nests. 



The Sand-martin (Ootile riparia) often makes its appearance at 

 the end of March, and commences to leave at the end of August 

 and in September. The genus Cotile has a tuft of feathers only 

 on the leg, just above the hallux. It nests in sandbanks, railway- 

 cuttings, and sand-quarry faces, making a slanting tunnel with 

 a large chamber at the end. On the floor of this chamber 

 are placed a few pieces of fine grass and feathers, where the 

 bird lays from four to six pure-white eggs. Sand-martins breed 

 in colonies, and are often attacked by sparrows, which they 

 occasionally defeat when large colonies are invaded. Like the 

 two preceding species, insects form the sole food. 



Wagtails and Pipits (Motacillid^). 



The Motacillidse contain two genera of birds, the Wagtails 

 {Motacilla) and the Pipits (Anthus). The bill is nearly 

 straight, slightly notched at the tip, the mandibles nearly equal 

 in length, and their edges slightly compressed inwards. In the 

 Wagtails, the tail, which consists of twelve feathers, is long 

 and the feathers nearly equal; in the Pipits the tail is only 

 moderately long and slightly forked. The tarsus in the Wag- 

 tails is longer than the middle toe, but in the Pipits it is the 

 same length. The Wagtails are partially migratory in habits. 

 Five distinct species are now recognised in Great Britain. Of 

 these the Pied Wagtail (M. lugubris) and the Yellow Wagtail 

 {M. rail) are the most abundant ; the other three are the Blue- 

 headed Wagtail (M. flava), the Grey Wagtail (M. melanope), 

 and the White Wagtail (M. alba). 



The Pied Wagtail (M. lugubris) is a common bird throughout 

 Britain. They move southwards in the autumn, large flocks 



