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. It is 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 Megapodidae 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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