134 WHEN THE SWALLOWS- 
times they declare their independence by perching 
on the dense, strong vegetation of the marshes, but 
the wires are favourite roosts. This shows a ready 
adaptability. As the Swift, easily distinguished by 
its round tail and dull, sooty plumage, adopted 
chimneys in preference to hollow trees, so the 
Swallows, also feeders on the minute insects of the 
air, prefer the wires to their old and natural perches. 
The Bank Swallows organise the most conspicuous 
flocks. As is their custom, the place where they 
swarmed noisily in the evening, filling the air with 
their disturbed chattering and scarcely leaving room 
in the air for their insect food, will be left in the 
morning silent and deserted. Their plumage is dull, 
dark above and light below, and the dark breast band 
makes a conspicuous mark as they line up on the 
wires. They are industrious burro wers, and have 
reared their young in holes in the many favourable 
banks furnished by cliffs and ravines. The Barn 
Swallows, the most gaily decorated of the family, 
have already begun to leave for the south, but a few 
remain and will probably join the flocks of their 
relatives. Reddish breasts, glittering blue-green 
backs, and deeply-forked tails spotted with white, 
distinguish them from the other swift chatterers that 
pursue the insects rising from the marshes. They 
are good masons, and attach nests of mud to the 
rafters and eaves of barns. The Tree Swallow is 
