Behaviour of Birds 
i ng nr 
by the retreating Germans (British Birds 
Magazine, vol. xi. p. 67). The sites for nest- 
ing in the Péronne district were remarkable 
owing to the absence of buildings. SWAL- 
Lows often used the circular Nissen huts put 
up for the troops, and were extraordinarily 
tame andconfiding. A wooden porch, erected 
outside a ruined single-room cottage at 
Roisel, was used directly it was put up. 
Another pair made valiant efforts to build 
their nest under the hood of a R.A. battery 
lorry ; it went out regularly, but the birds 
carried on building operations on its return 
and only gave up after two or three days. 
A pair of SwALLows managed to stick their 
nest against the vertical wall of a windowless 
room used as an officers’ mess; the nest had 
no sort of support underneath (Jbis, 1918, 
vol. vi. p. 359). In the very heart of a 
shelled and ruined town SWALLOWS quietly 
perched on war-telegraph wires, before migra- 
ting, as though the turmoil of battle were a 
thousand miles away (Illustrated London News, 
25.1x.15). Preparatory to migration the 
SWALLOWS collected in flocks and might be 
118 
