246 THE STORY OF THE BIRDS 



and Rheas lay their eggs on the bare ground ; 

 the Cassowaries and Emus scrape out a small 

 hollow, placing a few bits of grass or various 

 plant-stems round the margin ; whilst the Kiwis, 

 more elaborate in their provision, excavate a short 

 tunnel in a chamber, at the end of which they make 

 a rude nest of dry fern fronds and other herbage. 

 We have already briefly indicated the usual 

 type of nest in each of the great avine groups, 

 so that it will be unnecessary to repeat it here. 

 To this, however, there were two exceptions, the 

 orders being too heterogeneous to admit of any 

 generalisation with regard to the nesting arrange- 

 ments. These were the Coraciiformes and the 

 Passeriformes; the former containing certain 

 species remarkable for their mode of architec- 

 ture, the latter a group in which nest-building 

 may, generally speaking, be said to reach its 

 highest degree of perfection. It is in these 

 groups, therefore, that a more detailed account 

 of the various types of nest seems to be most 

 necessary. The Kingfishers, for instance, are 

 very interesting in their method of nesting. 

 Many of the species tunnel into banks of rivers 

 and pools, forming a gallery several feet in 

 length, the end of which is enlarged into a 

 kind of chamber. Here a heap of fish-bones is 



