in ANIMAL LIFE IN THE TROPICAL FORESTS 299 



sound very like the puff of a locomotive, and which can some- 

 times be heard a mile off. They mostly feed on fruits; and 

 as their very short legs render them even less active than the 

 toucans, the same explanation may be given of the large size 

 of their bills, although it will not account for the curious 

 horns and processes from which they derive their distinctive 

 name. The largest hornbills are more than four feet long, 

 and their laboured noisy flight and huge bills, as well as their 

 habit of perching on the top of bare or isolated trees, render 

 them very conspicuous objects. 



The Picariae comprise many other interesting families 

 as, for example, the puff-birds, the todies, and the humming- 

 birds ; but as these are all confined to America we can hardly 

 claim them as characteristic of the tropics generally. Others, 

 though very abundant in the tropics, like the kingfishers and 

 the goatsuckers, are too well known in temperate lands to 

 allow of their being considered as specially characteristic of 

 the equatorial zone. We will therefore pass on to consider 

 what are the more general characteristics of the tropical as 

 compared with the temperate bird-fauna, especially as exem- 

 plified among the true perchers or Passeres, which constitute 

 about three-fourths of all terrestrial birds. 



Passeres 



This great order comprises all our most familiar birds, 

 such as the thrushes, warblers, tits, shrikes, flycatchers, 

 starlings, crows, wagtails, larks, and finches. These families 

 are all more or less abundant in the tropics ; but there are 

 a number of other families which are almost or quite peculiar 

 to tropical lands and give a special character to their bird- 

 life. All the peculiarly tropical families are, however, con- 

 fined to some definite portion of the tropics, a number of 

 them being American only, others Australian, while others 

 again are common to all the warm countries of the Old 

 World ; and it is a curious fact that there is no single family of 

 this great order of birds that is common to all tropical regions 

 and confined to them, or that is even especially characteristic 

 of the tropical zone, like the cuckoos among the Picarise. 

 The tropical families of passerine birds being very numerous, 

 and their peculiarities not easily understood by any but orni- 



