254 BIRDS OF THE DISTRICT OF GEELONG 
Much mystery still attaches to the nesting-habits 
of these birds. One sometimes finds half a dozen to 
twenty nests in an area of, perhaps, a hundred yards 
square; they are built either in she-oak, bursaria (prickly 
box), or gum trees, or in an acacia hedge ; enormous 
structures of sticks, domed, with a spout entrance 
on the outer side of the tree (they are always placed at 
the extremity of a branch) near the top. The 
entrance generally appears closed, as if the birds 
pulled twigs across it when they left. Rarely have 
I known more than one nest in one of these groups to 
contain eggs. It may be that the birds build a lot 
of dummy nests, or use some of them as camping- 
places only. Nor do we know whether the whole 
flock builds the nests co-operatively, or whether each 
pair is responsible for its own arrangements. 
The eggs number up to six, and are laid on a bed 
of soft powdered bark, or, as it has sometimes appeared, 
dry horse- or cow-dung. They are whitish in ground- 
colour, lightly blotched with purple and crossed and 
re-crossed with fine hair-like lines of black, which 
give a curious marbled appearance. These hair-lines 
rub off easily when the eggs are fresh, and seem to 
be caused by the deposit on the surface of the egg, at 
the moment of extrusion, of a very fine filmy web. 
Towards the end of July most eggs are laid. I 
have also found them in August, but rarely later. 
