Some Foreign Bird Architects. 



purse-shaped nest, suspended at its apex from some 

 slender topmost branch. 



Two most remarkable nest-builders are the Aus- 

 tralian Mallee Bird (Leipoa ocellatd) and the Mound 

 Bird (Megapodius tumulus), both of which build upon 

 the ground mounds of considerable dimensions which 

 are used as nests. The Mallee Bird, according to 

 Gilbert, selects as its nesting site ^densely wooded, 

 gravelly hills on which the forest growth of tall euca- 

 lyptus trees overshadows the thick undergrowth. Here 

 the bird makes its mound by scratching up the gravel, 

 and mixing with that intended for the interior of the 

 mound a quantity of plant material, so as to form a regular 

 hotbed as it were ; for this central mass in which the eggs 

 are deposited soon begins to ferment and decay, so that 

 the temperature rises as high as 89 Fahrenheit, and 

 sufficient warmth is generated to incubate the eggs. 

 Of the way in which the Mallee Bird constructs this 

 curious nest, or natural incubator, Sir George Grey 

 has given the following account : " The mound ap- 

 pears to be constructed as follows. A nearly circular 

 hole, about eighteen inches in diameter, is scratched 

 in the ground to a depth of seven or eight inches, and 

 filled with dead leaves, dead grass, and similar mate- 

 rials, and a large mass of the same substances is placed 

 all round it upon the ground. Over this first layer a 

 large mound of sand, mixed with dry grass, etc., is 

 thrown, and finally the whole assumes the form of a 

 dome. When an egg is deposited, the top is laid 

 open and a hole scraped in its centre to within two or 

 three inches of the bottom layer of dead leaves. The 

 egg is placed in the sand just at the edge of the hole, 



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