74 HANDBOOK OF BRITISH INLAND BIRDS 
call, repeated time after time, as it flits and runs 
among the big upper timber or on the breadth of 
a trunk. It nests in late April in a hole in a tree, 
or, more rarely, a wall. Like the Tits, it takes a 
hole ready-made, and does not excavate one for 
itself, like the Woodpeckers, though an old nest- 
tunnel of the Green Woodpecker is one of its most 
favourite situations. The most interesting point 
in its nesting habits is its v^^ay of plastering up, in 
most cases, the mouth of its chosen hole with grit, 
clay, and sand until there is just room for its own 
body to pass. This clay ring or stopper has a 
very odd and striking appearance, let in, as it were, 
on the side of a tree-trunk or bough, and is a very 
tough and well-made piece of pottery. The nest 
itself is a loose and rather scanty bed of small 
twigs, moss, dry leaves, and especially scales and 
fragments of soft bark. Five or six eggs are laid, 
which cannot be distinguished with certainty from 
those of the Great Tit. Their average size, 
however, is the least trifle larger, and the spots 
have usually a slightly heavier and more clotted 
appearance, while there is generally a darker 
brownish tinge in their red. 
