NESTING OF SOLITAIRE 
the eggs to hatch themselves, the young birds can fly 
when born, instead of emerging either as fluffy balls 
without proper feathers, like the common fowl, or naked 
and featherless lumps of fat, like the young hornbill. 
This extraordinary habit of nest building in common 
seems to us to be the extreme of the gregarious nest 
building of some other birds, such as the rook. Place 
the nests closer together and they fuse into a common 
dwelling. An intermediate state of affairs is offered by 
the sociable weaver bird, which builds a great “ hive”’ 
with separate compartments for each pair of birds. The 
megapode is‘the last stage in the evolution of com- 
pound nest building, and the very mass of vegetable 
matter got together to form this common nest solves 
the problem of common brooding, for it renders it un- 
necessary. Itis just possible that a stage still further 
on, and on the downward path, speaking in an evolu- 
tionary sense, is offered by the extinct solitaire of Rodri- 
guez. This bird, according to Leguat, who knew it 
living three centuries since, erects a heap of palm leaves 
a foot and a half high, and sits thereon and upon a 
single egg. Perhaps this huge and inadequately con- 
structed nest, implying great labour at the most critical 
period of the bird’s life, has been its ruin, and it has 
really died out in consequence of diminished fertility 
and want of co-operation. Leguat speaks of the quarrel- 
someness of the birds during the incubation period, 
which loss of temper may have led to the separation of 
the birds at the nesting season, the only relic of a former 
co-operation being the unformed heap which does duty 
for a nest, and which plainly recalls the mounds of the 
mound builders of Australia and the islands of the East. 
It has been intimated that the Megapodide are Galli- 
naceous birds. It would seem from certain points in 
their structure, particularly from the fact that the hallux 
or great toe springs from the foot on a level with the 
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