MOTACILLA ALBA. 345 



in small numbers, but they migrate in large flocks along the west and east 

 coasts, and I think those I saw to-day were on their spring migration to 

 the north, along the east coast, and driven in by the violence of the storm ; 

 if so, the fact is interesting and worth recording as a very early migration, 

 and a month before the swallows. I shall see if they roost there 

 to-morrow." 



The writer wrote on the 19th stating that — 



" These birds roosted again last night in the same places as before, but 

 are not there to-7iight. I think the rise in temperature and south-east 

 wind have enabled them to cross the Firth and continue their migration." 



This quite agrees with my observations here. They are 

 fairly abundant here in winter, but they begin to migrate from 

 the south in March, proceeding as far north as the Orkneys, and 

 return south in October. With us they are seen at all seasons, 

 and it is interesting to see them alight on a small stone amongst 

 water, vibrating their body and moving their long tails up and 

 down like a horizontal pendulum in perpetual motion, as boys 

 use their arms when crossing some slippery ford ; or to see 

 them swiftly running after flies in a shallow stream, holding 

 up their tails — like a little girl her petticoat when wading on 

 the sands toying with the sea. When flies are near the 

 surface they run with great rapidity, and catch them with such 

 singular dexterity that their tiny feet make no impression on 

 the softest mire. They half run, half fly so nimbly that their 

 feet scarcely touch the surface, and are as expert on the watery 

 sand or mire as swallows are in the air. This singular celerity 

 is even more apparent in some swampy meadow where cows are 

 grazing in the midst of flies. They run and snatch one fly 

 then another before the first is swallowed, then dart to the 

 right, wheel to the left, or spring a few inches — or fly some 

 feet in the air, or pick them off the legs, noses, and bellies of 

 the cows in ceaseless, wonderful activity, the cows paying no 

 heed, for mutual interest makes strange friendships. They pair 

 in April, and begin the universal law of reproduction, and, 

 although not great songsters, they warble at this time a very 

 sweet low song. Their nests are generally by the side of a 

 burn or rocky bank by the seashore, on the trunk of a tree or 

 a wall, or among loose stones or a rick of hay, but rarely on 

 the level ground ; one built near the wheel of a turning lathe 

 in a shop near a burn, where the workmen went out and in, 

 and where the young were reared till they flew. I have got 

 them on the top of the Abbey wall, and on the old Culdean 

 vault at the Priory, and by the side of the Abbey mill dam, as 



