QUEENSLAND and NORTHERN TERRITORY 41 



northern, falling in with one conspicuous way ot 

 distribution of many of the Australian birds (map 

 14 A B). A walk along the Derwent or Tamar 

 Rivers, with a particularly observant eye, will show 

 the darker race. 



In group B we have in the Cape York Peninsula 

 and about Croydon the smaller race which is again 

 divided into a paler race at Tennant's Creek, N.T. 



The nearest relative of the genus outside Aus- 

 tralia lives in the Himalayas connecting with Aus- 

 tralia about Java. Here it lives along the margins 

 of the never ending rice fields. Frogmouths are 

 silent harmless useful birds. They perform their 

 serivces in orchard and forest in the gloaming as 

 most careful insect patrols. The bird and its nest 

 assimilate in colour closely with the tree, and can 

 scarcely be detected. Why is the young sometimes 

 rufous, giving us an hepatic phase? 



MOUND BUILDERS AND EMUS 



Plain coloured ground-birds may not attract like 

 Rifle Birds, but they are quite as interesting. Map 

 15, ABC, shows the distribution of the Mound 

 builders. Such a mass I have measured, with a 

 diameter of fourteen feet and a height of three: 

 composed of leafy rubbish with an immense amount 

 of heat within it. This is a self incubating nest 

 while the birds stand by acting as living thermo- 

 meters and removing the top san-i or replacing it 



