w V 



Coloration of the Mouths and Egys of Birds. 289 



probably of much service in associating them iu the miucls 

 of enemies, and this may have contributed to their 

 selection. 



4. Note on the Mouths of Adult Birds, 

 The mouths of adult birds are, in very numerous 

 instances, quite as brilliant and striking as those of 

 nestlings — often more so, — but in very few cases are they 

 the same. After the young bird leaves the nest the mouth 

 begins to alter, and at last takes on the full coloration of 

 maturity. The old nestling combinations between different 

 species have disappeared in the process, and new colour- 

 associations are formed, to a far greater extent amongst 

 unrelated birds than before. We have at Chirinda a 

 black-mouthed combination, an orange- mouthed association, 

 one with a yellow mouth with black extremities, another in 

 which the yellow of the last is replaced by pink, yet another 

 in which pink stands alone, and another which is entirely 

 yellow. I will describe them all in greater detail later, 

 and will figure members of some of the main associations 

 to show what diverse and unrelated species have a similarly 

 marked mouth when adult. 



It may at first sight seem far-fetched, but I cannot help 

 being convinced myself that the distinctive mouths of adult 

 birds are explicable in much the same way as I have 

 suggested for those of nestlings. 



Everyone who has made a large collection of birds must 

 have sometimes had the mortification of wounding one, 

 and will have observed that a bird at bay, as a rule, holds 

 its mouth open. I have had a good illustration of this. 

 One night I was awakened by the fluttering of my birds in 

 cages in the verandah. I went out. It Avas brilliant moon- 

 light, and an Owl, Syrnium ivoodfordi, was swooping in at 

 the cages. Stopped by the wire he each time wheeled 

 round and stooped again. The occupants of the cages 

 (insectivorous birds) were all down on the ground, terror- 

 stricken, with their bills wide-open. 



SER. X. VOL. IV. u 



