40 HANDBOOK OF BRITISH INLAND BIRDS 
their regular spring song. In spite of its sweet- 
ness of tone, this indefatigable *' tick-tack, tick- 
tack '* of the ChifF-chaffs might be called mono- 
tonous on its mere musical merits. But it is so 
welcome when it first falls on the ear in the end of 
March, as the signal that all the birds of summer 
are on their way to England, and so bound up 
with every feature of advancing spring in the 
woodlands, that no bird's song comes to be more 
grateful to the ear. The Chiff-chaff spends some 
time in settling down in its haunts before nesting, 
and it is after the middle of April before the 
thickening of the undergrowth generally gives it 
a fair opportunity to build in sufficient conceal- 
ment. Sometimes, however, if everything else is 
well forward, it does not wait for the new foliage 
to come, and builds among thick dry stems and 
brambles, or among the lower branches of a holly, 
where it sweeps the ground and is half choked in a 
litter of dry leaves. The nest is large for the bird, 
domed like the Wren's, and of similar or larger 
size, though with a much larger entrance. Its 
likeness to an old-fashioned oven in shape has given 
this bird and the Willow Wren one of their local 
names. It is built mainly of dead leaves and moss, 
with some dry stems and grass, and abundantly 
lined with feathers. It is generally a few inches 
above the ground, in brambles and mixed herbage 
