11 ANIMAL LIFE IN THE TROPICAL FORESTS 295 
Pigeons 
These are such common birds in all temperate countries 
that it may surprise many readers to learn that they are 
nevertheless a characteristic tropical group. That such is the 
case, however, will be evident from the fact that only sixteen 
species are known from the whole of the temperate parts of 
Europe, Asia, and North America, while about 330 species 
inhabit the tropics. Again, the great majority of the species 
are found congregated in the equatorial zone, whence they 
diminish gradually toward the limits of the tropics, and then 
suddenly fall off in the temperate zones. Yet although they 
are pre-eminently tropical or even equatorial as a group, they 
are not, from our present point of view, of much importance, 
because they are so shy and so generally inconspicuous that 
in most parts of the tropics an ordinary observer might hardly 
be aware of their existence. The remark applies especially to 
America and Africa, where they are neither very abundant 
nor peculiar; but in the Eastern hemisphere, and especially 
in the Malay Archipelago and Pacific islands, they occur in 
such profusion and present such singular forms and brilliant 
colours, that they are sure to attract attention. Here we 
find the extensive group of fruit-pigeons, which, in their 
general green colours adorned with patches and bands of 
purple, white, blue, or orange, almost rival the parrot tribe ; 
while the golden-green Nicobar pigeon, the great crowned 
pigeons of New Guinea as large as turkeys, and the golden- 
yellow fruit-dove of the Fijis, can hardly be surpassed for beauty. 
Pigeons are especially abundant and varied in tropical 
archipelagoes, so that if we take the Malay and Pacific islands, 
the Madagascar group, and the Antilles or West Indian 
islands, we find that they possess between them more different 
kinds of pigeons than all the continental tropics combined. 
Yet further, that portion of the Malay Archipelago east of 
Borneo, together with the Pacific islands, is exceptionally 
rich in pigeons; and the reason seems to be that monkeys 
and all other arboreal mammals that devour eggs and young 
birds are entirely absent from this region. Even in South 
America pigeons are scarce where monkeys are abundant, and 
vice versa, so that here we seem to get a glimpse of one of the 
