SWALLOWS AND MARTINS. 453 



The latter have a very weak triangular depressed bill (Fig. 254), 

 and have all the toes directed forwards in walking ; they have 

 obviously, therefore, the nearest alliance to the Goatsuckers. 



The former have 

 a stronger bill ; and 

 the hind toe is in- 

 serted quite at the 

 back of the tarsus. 

 The Swallows are 

 remarkable for their 

 extreme activity, and 

 for the elegance of 



FIG. 254. HKAD AND FOOT OF WINDOW SWALLOW, OR , 



HOUSE MARTIN. tneir movements ; 



and these qualities, 



combined with the attachment which they show to human 

 habitations, render them universal favourites. They nestle in 

 holes ; or against the face of rocks, buildings, or trees, in which 

 case they construct a nest of mud, or of twigs held together by a 

 glutinous saliva. Three species are well known in this country 

 as summer visitants : the Common Swallow ; the House, or 

 Window Swallow, or Martin ; and the Bank Swallow, or Sand 

 Martin. They resemble each other very closely in their 

 habits ; flitting about during the whole day in search of their 

 insect prey ; and especially frequenting the neighbourhood of 

 pools, and other spots where insects are numerous. The most 

 remarkable peculiarity of their flight, is the facility with which 

 they turn on the wing ; for they can double back, not merely at an 

 angle, but at a very acute angle, almost, in fact, returning upon 

 their previous course ; and this without the least appearance of 

 effort. The two first of the species just named construct their nest 

 against the walls of buildings, building them up of particles of 

 earth attached by their glutinous saliva ; but the last burrows 

 into sand-banks, often to a considerable depth, making the 

 entrance slope upwards so as to prevent the rain from beating 

 into it, and lining the interior with feathers and soft vegetable 

 fibres. The male and female work alternately at the excavation ; 

 one feeding, whilst the other is carrying it on. 



