14 ELEMENTS OF ORNITHOLOGY. 
A very interesting form, called the Tooth-billed Pigeon 
(Didunculus strigirostris), inhabits the Samoan Islands, where it 
feeds on plantains. It used to be an entirely, or almost 
entirely, ground-bird, but is said to have taken to flying up 
into trees to avoid cats and other enemies introduced of late 
years by man into the region it inhabits. Thus it can fly toa 
certain extent when it needs to do so; but its main interest con- 
sists in the fact that of all existing Birds it is the one which most 
resembles the extinct Dodo, which could not possibly fly at all. 
Not less familiar to us than Fowls and Pigeons are our 

The Mallard (Anas boscas). 
Ducks and Geese. Of these there are very many species, and 
some are found almost all over the world. 
Our Domestic Goose is derived from the Grey Goose (Anser 
cinereus), the natural range of which extends over Europe and 
Central Asia. There are some fourteen species of the genus 
Anser, and of allied forms there are very many more—some of 
them being found in one region or another almost all over the 
world, save that the true Geese eschew the Tropics. In spite of 
their webbed feet, the Geese generally, like the Domestic 
