THE PRINCIPAL BIRD GROUPS 71 



of their moulting have been dwelt upon in 

 the previous chapter. The food is partly of a 

 vegetable and partly of an animal character. 

 The nest is placed on the ground, more or less 

 plentifully lined with down from the parent, in 

 holes of trees or cliffs, in burrows, and excep- 

 tionally in low bushes or trees. The eggs are 

 numerous, buff or green of various shades, or 

 white in colour, with considerable gloss. The 

 young are hatched covered with down. These 

 birds with few exceptions fly well, swim or dive, 

 and many are of migratory habits. Upwards of 

 two hundred species are included in this order, 

 all save nine belonging to the Anseres. 



The next order we shall notice is a small 

 one, the Gruiformes or Cranes and allied birds. 

 Small as this order is, it is a most hetero- 

 geneous one, and is composed of the Cranes, 

 the Limpkins, the Kagu and the Trumpeters. 

 Each of these is worthy of at least family 

 rank, the Cranes (nineteen species) constituting 

 the Gruidae, the Limpkins (two species only) 

 the Aramidae, the Kagu (one species) Rhinoche- 

 tidae, and the Trumpeters (six species) Psophiidae. 

 Some authorities include the Sun Bittern (Eury- 

 pygidcc) and the Seriemas (Cariamidac) in the 

 present order. Both represent swimming forms 



