296 THE BIOLOGY OF BIRDS 



Birds with no Nests, — In many birds the labour of nest- 

 building is scamped or shirked. Thus the tern makes no 

 more than a mere scraping on the sand or shingle, and the 

 same is true of divers, thick-knees, and sand-grouse. Razor- 

 bills and guillemots place their single egg on a bare ledge of 

 rock, where its shape gives it some chance of not being 

 knocked over or blown over into the sea. The stone-curlew 

 and the night-jar make no nest nor any preparation of the 

 soil, and yet year after year they come back to the same 

 spot. 



A slight improvement may be seen in many of the gulls, 

 sandpipers, and plovers. They lay their eggs in shallow 

 hollows in the ground, but as incubation proceeds a breast- 

 work of stems and leaves may be added. Many ducks are 

 about the same level ; they make a slight depression and line 

 it sparsely with down — the first hint of the thick quilt made 

 by the eider. The ringed-plover usually lays its eggs in the 

 shingle, where they are most effectively lost to ordinary 

 vision, and Professor Newton calls attention to the interesting 

 point that when the bird breeds on grass uplands it still 

 paves its nest with small stones — the ways of the past living 

 on in instinctive promptings even when they have ceased to 

 be relevant. 



In not a few birds the only care is to bury the eggs, which 

 recalls the habit of many reptiles, such as crocodiles. The 

 female ostriches scrape holes in the sand and bury their eggs, 

 but they also incubate during at least part of the day. The 

 males sit at night. The Kiwi of New Zealand puts its single, 

 relatively large egg in a hollow among the rhizomes of the 

 tree fern. Some of the Megapods or Mound-birds bury 

 their eggs in the sand and leave them to hatch by the heat of 

 the sun, but others heap a huge hotbed of dead leaves over 

 the spot. This may be 5-6 yards high and 10 yards round, 

 and many mothers share in its making. Alfred Russel 

 Wallace noted that the mother mound-birds may come from 

 a distance of 10-15 niiles to suitable places in Celebes, 

 near hot springs, for instance. They make their mound, 

 lay their eggs, and depart, for there is no food for them. The 



