THE BIRDS OF AUSTRALIA. 
according to the environment and climatic conditions. The egg is of an un- 
polished delicate salmon pink colour varying to a warm pinkish red when freshly 
taken from the mound, but it readily fades to an earthy brown. Occasionally eggs 
have been found that are white, but they usually have an epidermis or coating 
which is readily scraped off, showing a buff- white shell beneath. As the hatching 
proceeds, this epidermis chips off in patches as well as fades. Although no 
absolute plan of ovi-disposition in the mound can be stated, yet it is certain that 
the eggs are laid in tiers, the usual number in the bottom tier being four. However, 
I have found five eggs, the odd or fifth egg was tilted, and as this mound had 
been opened once before to make observations, the finding of the fifth egg in the 
lower tier was no doubt the result of abnormal conditions due to interference. 
Sometimes, however, only three eggs constitute the lower tier which is the first of 
the series deposited in the egg chamber. There is no regular spacing between the 
eggs forming any one tier, but the eggs comprising it are usually on the same plane, 
being uniformly level, yet this formation is not constant. The eggs are separated 
from one another by six to twelve inches of sand and are placed close to the 
solid interlaced decaying vegetable matter forming the wall of the egg chamber. 
This position serves two purposes, firstly, it brings the eggs near to the warmth 
radiated by the decomposing vegetable mass, and, secondly, it also prevents undue 
lateral pressure that would otherwise fall on the weakest part, i.e., the side of the 
egg as it reposes vertically in the mound and thus prevent the egg from being 
crushed by the superimposed mass of sand or gravel which is usually heaped 
about two feet high above them as well as being banked several feet thick 
through the walls that compress the material of the egg chamber on all its sides. 
Above the first or bottom tier three or four more tiers or circles of eggs, one tier 
above the other, are deposited, with no one egg immediately over another ; 
sometimes the tiers will number ; — 
Tier. No. I Mound. 
First (Bottom) 4 eggs 
Second . . 5 „ 
Third . . . . 3 „ 
Fourth . . — 
Example. 
No. 2 Mound. 
4 eggs 
6 „ 
4 „ 
No. 3 Mound. No. 4 Mound. 
3 eggs 5 eggs 
99 
99 
6 
4 
2 
99 
99 
99 
Usually three or four inches of sand divide the eggs in one tier from those in 
another, but this is not constant. The temperature of the egg chamber 
varies from 90 degrees to 97 degrees, which heat is sufficient to hatch out 
the eggs successfully. The bird, however, as before stated, regulates the 
temperature according to the external atmospheric conditions, thereby earning 
the cognomen of Thermometer Bird. The usual clutch of eggs laid totals sixteen 
eggs. The egg is of large proportions when compared to the size of the bird 
which lays it, and is excellent eating, either in a cooked or raw condition.” 
52 
