Tooth-billed Pigeon 49 



civilization prevailed in the shape of cats and rats, the 

 former devouring the birds and the latter their eggs, and 

 speedy extermination appeared to be the fate in store for 

 the Didunculus. It then appears that the Pigeons began 

 to use their wits, and did not quite see why they should be 

 wiped off the face of the earth, as their distant relatives the 

 Dodo and the Solitaire had been, and they not only began 

 to use their wings to save themselves, but changed their 

 mode of nidification, and took to building their nests in 

 trees. The Rev. S. J. Whitmee, who was for long a mission- 

 ary in Samoa, credits the Didunculus with a high intel- 

 ligence, and writes — " It has probably been frightened 

 when roosting, or during incubation, by attacks of cats, and 

 has sought safety in the trees. Learning, from frequent 

 repetition of the fright, that the ground is a dangerous 

 place, it has acquired the habit of building, roosting, and 

 feeding on the high trees ; and this change of habit is now 

 operating for the preservation of this interesting bird, which 

 a few years ago was almost extinct." * 



Amongst the Swimming Birds there are also some 

 remarkable forms, and some of the most curious of these 

 are the Darters or Snake-Birds (Ptotus), which are found 

 in the temperate and tropical portions of both hemispheres. 

 These long-necked birds are allied to our Cormorants 

 {Phalacrocorax), and have much similarity in habits to the 

 latter, though they are inhabitants of rivers and swamps, 

 rather than of the sea-coasts like the Cormorants and 

 Shags. The latter have a remarkably strong hooked bill, 

 recalling that of an Accipitrine bird, whereas the Darters 

 have a long thin bill which is furnished with saw-like edges 

 turned at a backward angle like a barb, so that a fish 

 transfixed by the unerring aim of the Darter's bill has no 

 chance of escape, and with this bill a wounded bird is 

 capable of inflicting a severe wound on its captor. In 

 1 Proceedings ' of the Zoological Society, 1874, p. 184. 



