1922.] Moxnd-lntiJding Birds of Australia. 1()1 



her neck and breast against the cog-chamber is qnite unique, 

 and suggests the possibility that this action is part of the 

 method by which tlie birds ascertain the temperature of the 

 enveloping sand. 



My opportunities ot" personally observing these interesting 

 and shy birds in their native haunts have been too brief and 

 too far apart to furnish conclusive dat:i, but, from my own 

 observations and from the information supplied to me from 

 time to tin)o by dwellers in the back blocks, 1 have long felt 

 satisfied that it is the regular habit of the Mallec-Fovvl to 

 open out tlie nesting-mounds almost down to the eggs on 

 clear, hot, sunshiny days — this opening being done as soon 

 as the sun is well u[). The sand is rather widely distributed 

 and heated by the sun^s rays to a high degree. The birds 

 always return fairly early in the afternoon, which accounts 

 for Mr. Mann's observation " that he is under the impression 

 that they are not long left open" — he seldom passes the nesting- 

 mounds on his way home from work till late in the evening, 

 — the object of the birds' return being to restore the heated 

 sand to the nest. The accumulated heated sand retains 

 its high temperature, or a large amount thereof, for some 

 days. It seems evident that the mounds are not opened 

 by the birds (except tor actual egg-laying) on cool cloudy 

 or drizzly days, the birds awaiting the return of a clear 

 sky and the heating ])Ower of an unimpeded sunshine. 

 In the districts where Mallee grows this is tlie normal 

 weather. 



In my lectures on Australian Bird-life before Agricultural 

 and Horticultural Societies and other Public Bodies in the 

 State of South Australia, I have often during the last few 

 years told the story of the Leipoa, and expatiated upon the 

 wonderful adaptation of its methods to changed climatic 

 conditions, suggesting the following hypothesis by way 

 of explanation. 



As is well known, the interior of Australia used to be 

 favoured with a much heavier rainfall than is now the case. 

 The discovery of numerous skeletons of the huge extinct 

 Jjiprotodon half-buried in the dry bed of what was once a 



