228 THE USEFUL BIRDS 



weight of sand with which they are covered ; the ground 

 round the eggs is generally slightly damp. Sometimes when 

 the parent bird is opening up the mound she scratches a hole 

 in the top of one of the eggs ; the sand then gets in, and, 

 mixing with the contents, forms, when dry, a compact sandy 

 mass, completely filling the shell. On one occasion I found 

 five such eggs in one mound. 



" There has been much discussion as to whether the young 

 birds can make their own way out of the soil unaided by their 

 parents. In order to settle it I covered in with wire netting a 

 nest with several eggs in it, so that the parents could not open 

 it up, and found all the chickens, when they came to maturity, 

 dead in their shells. Then, again, on taking the eggs from a 

 nest you often find chickens in their eggs which are ready to 

 hatch, especially in the lower tier, so much so that when 

 opening the egg you have to hold the young bird firmly to 

 prevent it escaping and running away. Then, on other 

 occasions, you find chickens near the surface under the sand, 

 apparently working their way out unaided. The old birds 

 open up the nest to a certain extent at daybreak, and it is 

 probable that any chickens that may be ready to come out, 

 especially in the lower tiers, do so then. Moving the sand 

 also prevents it from becoming set. But the chickens that 

 hatch from the eggs of the top tier, the sand therfe not being 

 set so tightly, and being drier and running more freely, are able 

 to force their own way out, and, judging from the experiments 

 I have made, I should say this was usually the case. On 

 opening up the nest that had been wired in, I found that the 

 sand had set rather tight, especially where the eggs were, and 

 this I should say fully accounted for the young birds being 

 unable to come out. 



" When the mound is opened up during the day and eggs 

 abstracted, the parent birds repair the mound shortly 

 after the intruder has gone away, showing that either one 



