^°' iToS^ 1 Mattingley, Thermometer-Bird or Mallee-Fowl. Ky 



building birds have similar characteristics, and are the same 

 shape, the apices or ends being of uniform size or nearly 

 so, as well as the shell of the eggs of both being brittle, 

 whereas formerly in the earliest reptiles they were soft-shelled, 

 then we have evidences of a common origin and the rise of a 

 mound-building habit on reptilian lines. This is especially 

 noticeable when we know that the young of both the mound- 

 building birds and the crocodiles are able to take care of 

 themselves immediately after birth. Further evidence of this 

 contention is to be found in that the Lipoa knows the value of 

 maintaining a correct temperature in the mound so that its eggs 

 will hatch out successfully. All the bird's energies are centred 

 in this object — the pleasure of brooding is foreign to their 

 nature. Their only anxiety is to regulate the temperature of 

 the egg-chamber, as will be shown later on, as well as to protect 

 their eggs in some degree from the depredations of their natural 

 enemies. It is also significant that the Lipoa forms its mound 

 in or near the dried-up bed of an inland sea or river basin, in 

 the waters of which they once probably existed in their reptilian 

 form, afterwards gradually metamorphosing with the physio- 

 graphic change of their habitat when the inland sea or river-bed 

 changed into dry land and became in course of time clothed 

 with its present stunted growth. It is suggestive, too, that a 

 member of the Megapode family {AI. hrazieri), inhabiting Savo, 

 an island in the Solomon Group, still retains a more primitive 

 and reptilian method of incubating its eggs. This bird simply 

 digs a hole in the sand of the sea-shore wherein to deposit its 

 eggs. Doubtless owing to its isolation, and thereby the 

 relatively smaller proportion of the enemies of its eggs, this 

 species has not been compelled to develop a more specialized 

 method of incubation. Probably before the land bridge which 

 joined these islands to the continent of Australia became 

 broken, all the members of the family of Megapodiidce shared a 

 common and a similar method of incubating their eggs to that 

 of M. brazieri. Although the Lipoa, as before stated, frequents 

 mixed country, the exception proves the rule, since it is in the 

 areas covered with sandy wash or silt created by the action of 

 water that we find them most numerous. A probable ancestor 

 of the mound-builders was the fossil bird Chosornis prceteritus. 



Choosing a Site for Nesting Mound. — In choosing a 

 site for its nesting mound the Lipoa, in its Mallee habitat, 

 usually selects an open space in the scrub with a break or 

 opening to the north or east, so as to admit the sun's rays, which 

 have so important an influence on the incubation. Bushmen 

 that have become lost, and who are acquainted with this fact, 

 are enabled to note the points of the compass approximately 

 when they happen on a mound in the scrub. On the opposite 

 side of the mound the scrub is usually dense, and offers protection 



