ON INCUBATION. 327 



The Spoonbill (P. leucorocUa) does not leave its eggs 

 unprotected. 



Finally, the Grebes (Podicipedidse) are ovitegous. No 

 doubt numerous eggs are saved by the presence of the 

 bird, which would be lost, even covered as they are, if 

 they were left for some days ; for many nests are very 

 exposed, and egg-sucking birds would have their attention 

 drawn to them by the Grebes when in the vicinity of their 

 home. Also, it seems possible, as the eggs are frequently 

 laid almost in the water, that they would suffer from its 

 effects if they were not constantly incubated, although 

 the nest itself generates a certain amount of heat. 



