BIEDS AND THE AETS 111 



seas of higher latitudes, or the brilliant off-shore seas of 

 the tropics, the white under-plumage of the adult birds is 

 undoubtedly best suited to this end. I have frequently 

 been struck when cruising in the shoal waters on the 

 shores of this possession by the beautiful pale green shade 

 reflected upon the breast feathers and underwings of the 

 white terns which abound here, the tint being an almost 

 exact counterpart of the colour of the water from which 

 it is thrown. No other colour but white would mirror 

 this hue, and the tern is thereby rendered less visible to 

 the fishes below. I am aware that this line of reasoning 

 does not apply to the shear-waters and frigate birds, but 

 these birds are seldom seen fishing in shallow waters. 

 They appear to go farther afield where the sea is dark blue 

 and deep. Sometimes they may be seen hovering in 

 cloud-like numbers above a shoal of large fish which are 

 disporting themselves splashing about at the surface. At 

 such times they perpetually dash down, and apparently 

 pick minute pieces out of the bodies of the fish. The 

 latter seem to be totally oblivious of the presence of the 

 birds, so in this case the question of " protective " colour- 

 ing does not arise. The most conspicuous exceptions to 

 the above theory are, I conjecture, the cormorant and the 

 shag. I have never had the pleasure of seeing these birds 

 fishing on the coasts of Great Britain. It would be in- 

 teresting to know whether it is their habit to dart down 

 upon their prey from the upper air, after the manner of 

 gannets, or whether they watch their opportunities from 

 a rock like themselves. The so-called shags in Queens- 

 land pursue the latter method when I have observed them 

 on the inland creeks and rivers of that country. 



F. E. BARTON. 



July 26, 1902. 



NOTE. Shags and cormorants catch fish by diving from 

 the surface of the sea, turning a graceful semi-circle in the 

 air, and then plunging head first. 



