312 THE BIOLOGY OF BIRDS 



malcos make for the shade as quickly as possible. It is not 

 unscientific to wonder if parents and young ever meet. 

 There must be some need for introductions. 



The strange name " Thermometer Bird " is given to 

 a South Australian mound-bird {Lipoa ocellata) whose 

 behaviour makes a fitting climax. The birds choose a clear- 

 ing in the low bush, where there is loose sandy soil, and the 

 clearing must be open to the sun (to the north or east), and 

 it is usually protected by bushes from the prevailing wind. 

 Taking time by the forelock the two birds begin operations 

 long before the actual breeding season, (i) First of all, 

 they dig a circular pit about a foot deep, piling up the 

 scratched-out earth in an outer rampart. In the circular 

 pit they make a heap of withered leaves and other parts of 

 plants, the collecting of which means very heavy work and 

 terrific scratching even for a megapod. (2) The next step 

 is to suspend operations. The collection of leaves and twigs 

 is left for four or five months to soak in the rain, and it 

 begins to decay. (3) But after a while a third chapter begins. 

 The birds make a firm nest or egg-chamber in the centre 

 of the compost-heap. It has walls of interlaced twigs and 

 fibres, and a floor of mixed sand and plant-remains, what 

 might almost be called vegetable mould. Over this a mound 

 of leaves and twigs is piled up till it stands about a yard 

 high and has a diameter of perhaps four yards. Sand is 

 thrown all over it, the whole business involving much time 

 and much hard work. (4) The fourth chapter begins six 

 to nine days after the completion of the mound. The 

 builders return to the scene of their prolonged labours and 

 open the mound carefully, making a gallery near the top, 

 so that the internal nest is reached. In this nest the hen lays 

 an egg, fixing it upright, broad end up, in the mould, and 

 staying it with twigs. Then the mound is made tidy and 

 off they go. Every three or four days, about nine o'clock 

 in the morning, they turn up at the mound and open it up 

 again to get at the nest, in which the hen puts another egg. 

 At length there are about fourteen eggs, in three tiers, four 

 or five in each tier, all in the same position, and all securely 



