OPEN NESTS 157 



nothing appears to be known, but there are facts 

 which seem to suggest a great divergence from the 

 normal Rail methods of reproduction. We may also 

 state that generally the Rails are more or less solitary 

 during the breeding season, but social tendencies are 

 not infrequent amongst such forms as the Moorhens 

 and Coots. 



Passing over the Game Birds, Sand-Grouse, Pigeons, 

 Bustards, Plovers, Sandpipers, etc.. Gulls and Auks, the 

 nesting arrangements of which having already been 

 dealt with, we have now to consider the nests of such 

 raptorial birds (Falconiformes) as come within the 

 limits of the present chapter. Here we are con- 

 fronted with a great amount of variation in the 

 degree of architectural skill. Some species, as we 

 have already seen, are practically of non- nest-building 

 habits, but annex the deserted homes of other birds 

 {conf. p. 47) ; others are included in the chapter deal- 

 ing with the crudest nest-forms. On the other hand, 

 many of the species in this order construct more or 

 less elaborate open nests, and these we will proceed 

 briefly to describe. Beginning first with the Vultures, 

 we shall find a most remarkable variation in the nest- 

 ing methods. Some of these birds make no nest 

 whatever, or only the slightest provision for their 

 eggs ; or they may annex the deserted home of 

 another bird as the Egyptian Vulture frequently does. 

 Others, however, build large and elaborate structures. 

 The Griffon Vulture (Gyps fulvus), for instance, breeds 



