CORMORANT AND OTHER DIVERS 39 



bait. Of the under- water photographs on the 

 plate, the lower was taken one-fifth of a second 

 after the first, and it will be seen how the 

 " flash " altered in that time. 



When the entire film from which these two 

 illustrations were cut is shown, the penguin is 

 not detected, because the eye of the observer is 

 arrested by the flash, flash, flash of the white 

 plumage. 



The next question which arises is : Are the 

 "flashes" from a diver arranged by Nature so 

 that the bird attracts its prey, or are these flashes 

 a scheme for recognition among gregarious 

 divers ? 



The cormorant has a glossy plumage so as to 

 permit the bird to slip rapidly through the water, 

 and the " flash " is therefore merely accidental, 

 but for all that none the less effective. 



Whatever was the original purpose in the 

 arrangements of white in the plumage of such 

 birds as the great northern diver and the 

 penguin, they certainly flash under the water 

 like shoaling fish, and if these marks were in- 

 tended for recognition, personally, I think they 

 would have been better arranged. 



Before I pass on from the consideration of 



