ON THE HABITS OF THE STONE CURLEW. 445 



clear of the egg, and must have been done immediately after my 

 visit at 6 p.m. 



The young birds and the eggs are both protective in colour ; 

 but a broken egg-shell, with the remains of membranes and 

 blood-vessels inside, is by no means so. In fact, it is a kind of 

 sign-post pointing out the whereabouts of the nest to all comers. 

 No one passing the nest could fail to see the broken egg-shell 

 lying on the ground, and a Stoat or a Book would observe it even 

 more readily. 



Young Thick-knees are able to leave the nest at a very early 

 period ; but I doubt if this period is ever less than twelve hours, 

 and in the case of an egg remaining unhatched for some hours after 

 the other (as happened here), the danger of leaving the egg-shell 

 would be very great. 



I believe that an almost constant law might be formulated, 

 that birds which make open nests upon the ground remove their 

 egg-shells immediately the young are hatched. This habit is 

 noticeable not only in the birds referred to, but in others building 

 in similar situations ; for instance, the Green and Golden Plovers, 

 Vanellus cristatus and Charadrius pluvialis, and the Common and 

 Lesser Terns, Sterna hirundo and S. minuta. I have found a 

 nestling Common Tern in a nest with two eggs, but no sign of an 

 empty egg-shell, and have seen a Green Plover's nest with eggs 

 one day sprung, and on returning the next day have found nothing 

 whatever — neither nestlings nor egg-shells. From this, I think, 

 we may conclude that the parents removed the egg-shells as each 

 bird was hatched. The young cannot leave the nest so long as 

 an egg on the point of hatching remains in it, since the mother 

 must sit on this egg, and will brood over the newly-hatched nestling 

 at the same time. 



I have seen a few pounded fragments of shells in the nest of 

 a Kedshank, Totanus calidris ; but this bird hardly comes in my 

 category, since it does not build an open nest upon the ground. 

 The nest is generally placed in a tuft of coarse grass or short 

 rush, with a side entrance to it over which the parent bird draws 

 the grass like a curtain on leaving or entering. If a Redshank laid 

 absolutely in the open, like a Plover, I have no doubt the egg-shells 

 would be destroyed or removed at once by the parent birds. 



On the other hand, look at the game birds which build on 

 the ground, but conceal their nests ; with them the broken egg- 



