LORD CRAWFORD'S TERN 45 



first visit to the island. This skin had remained 

 undescribed, owing to the fact that the bills of 

 both forms become totally black in the dried 

 skins, the light blue of the Pacific and Indian 

 Ocean birds turning black within two days after 

 the bird has been skinned. 



Gygis crawfordi lays a single egg, either on a 

 narrow ledge of rock or else on the branch of a 

 dead tree. No nest is made, the egg being laid 

 in a cleft or in a small hollow, and some of those 

 we found were placed in such a shallow depression 

 on the bare branch of some dead tree that a slight 

 push was sufficient to dislodge them. 



The way these eggs are balanced is extraordinary 

 but the tenacious hold of the young bird in a 

 similarly insecure position is perhaps more aston- 

 ishing. Several times I drove a tern suddenly 

 from its nest for the purpose of seeing if the young 

 bird could retain its position. Although the old 

 bird in every case left the nest in such a hurry as 

 to upset the balance of the young one, the latter 

 clung on and pulled itself back in a few seconds 

 by means of its sharp claws and bill. 



It was well for the birds that they could retain 

 their hold so cleverly, for the ground underneath 

 the trees was covered with land-crabs, which would 

 have quickly devoured any unfortunate young 

 bird falling from its nest. 



During the whole of the time we spent amongst 

 the colonies of these white terns we were continually 



