THE SAND MARTIN 85 



and the eaves or windows of a certain house are peculiarly well 

 adapted for sheltering nests ; so a number of Window Martins, 

 not having taken counsel together, but guided each by independent 

 choice, find themselves established sometimes so close together 

 that their nests have party walls, like the houses in a street. They 

 accordingly make acquaintances, and are sociable to a limited 

 extent. But Sand Martins go beyond this, they are comrades 

 banded together by municipal laws, which no doubt they under- 

 stand and obey, inhabiting dwellings which constitute a joint settle- 

 ment, returning without fail to the familiar haunt after every 

 annual migration, or if they desert a station, leaving no stragglers 

 behind, and pitching their camp anew in some locality which 

 common consent has pronounced to be an eligible one. They are 

 not, however, exclusive in their fraternization ; as they hunt in 

 society with their relatives the Swifts and Swallows, and even 

 accompany them in distant flights. I have repeatedly observed 

 Sand Martins flying about with others of the same tribe many miles 

 away from their homes. They may readily be distinguished, as I 

 have stated before, by their dingy mouse-coloured hue, smaller 

 size, and less forked tails. I have never had an opportunity of 

 watching a colony engaged in their mining operations at the busy 

 period of their year, that of nidification ; but from the description 

 by Professor Rennie [Bird Architecture) and that by Mr. R. D. 

 Duncan, quoted by Macgillivray, the sight must be most interesting. 

 The task of the older birds must be a light one ; not so, however, 

 that of the younger members of the flock. The former have neither 

 walls nor roofs to repair ; the holes which served them as nests the 

 previous year afford the same accommodation as before. All that 

 is needed is, that the remains of the old nest should either be re- 

 moved or receive the addition of a few straws and feathers to protect 

 the eggs and young from direct contact with the cold sand ; their 

 labours then are over. But the new colonists have a toilsome work 

 to perform before they can enjoy the gratification of bringing up 

 a family. The settlement is fixed probably in the perpendicular 

 face of a bank of sand, gravel, or clay, at an elevation from the 

 ground which varies from a few to a great many feet. Their claws 

 are sharp and well adapted for clinging, the beak short, rigid, and 

 pointed, no less well suited for excavating. Grasping the perpendi- 

 cular surface of the bank with their claws, and steadying themselves 

 by means of their tails, they commence operations by pricking a small 

 hole with their bills. This hole they gradually enlarge by moving 

 round and round, and edging off the sand with the side of their 

 bills, which they keep shut. Their progress is slow at first, but 

 after they have made room to stand on the excavation, they proceed 

 rapidly, still working with their bills, and carefully pushing out the 

 loosened sand with their feet. At one time the male, at another 

 the female, is the excavator. When their burrowing is impeded 



