70 MR. C. F. M. SWYNNERTON i 



watching the ground but taking no notice of the numerous 

 nightjars not far away. This does not prove much ; but the 

 visibility of the latter as they dart after their prey must, 

 in relation to such an enemy, more than counterbalance any 

 advantage that might be gained from noiselessness. The 

 correct view may be that moths, for example, deaf to all 

 noises that do not ordinarily imply danger, are nevertheless 

 sensitive to the vibration of wings, and that the ex{)lanation 

 of the nightjar's noiselessness is, after all, the one that 

 a[)plies to the owl's. That moths are sensitive to certain 

 kinds of vibration, just as bees are, may easily be proved by 

 anyone who will take the trouble and repeatedly disturb 

 only two or three of a number of moths that are feeding on 

 fruit and notice the usual effect on the rest. 



The excellent protection conferred on young nightjars in 

 the down by the procryptic coloration of the latter, its 

 mottlings matching the unevennesses of the bare ground in 

 which the nestlings lie, is too well know^n to be worth 

 mentioning here, except for the i)urpose of referring to the 

 manner in which the down, all round the bird, seems to lie 

 " to " the ground and, for visual purposes, join the bird on 

 to it. It is, if anything, rather specially noticeable in 

 Cosmetornis, I think, and the device is one that is still 

 more ])erfectly represented in the insect-world, some pro- 

 tectively-coloured larvse and the hairier species of ant-lions 

 (the perfect insects) being shaded off in the same way into 

 their surroundings by the "lie" of their peripheral hairs. 

 It is true that in other larv?e a not dissimilar device is used 

 to ward off ants. 



Pelecanus roseus, Gmel. 



On September 9th, 1915, Mr. Hicks came on a flock of 

 Eastern White Pelicans that appeared to contain from 

 seventy to a hundred individuals. They were all together in 

 an open, short-grassed vlei, close to the Umswirizwi lliver 

 near Chirinda (in Southern Rhodesia), resting and engaged 

 in preening their feathers. He shot two with ;i single bullet, 

 so close-packed were they, and secured a third with his shot- 



