"When they alight on a dry branch," says Captain Gosse, in his Jamaica chronicle, "their emerald hue is conspicuous and affords a fair mark for the gunner, but in a tree of full foliage their color proves an excellent concealment. They seem aware of this, and their sagacity prompts them to rely on it for protection. Often we hear their voices proceeding from a certain tree, or have marked the descent of a flock, but on proceeding to the spot, though the eye has not wandered from it, we can not discover an individual; we go close to the tree, but all is silent; we institute a careful survey of every part with the eye, to detect the slightest motion, or the form of a bird among the leaves, but in vain, and we begin to think that they have stolen off unperceived, but on throwing a stone into the tree a dozen voices burst forth into cry, and as many green birds dart forth upon the wing."
The gorgeous macaws, on the other hand, seem to owe their color contrasts to sexual selection. "Ya son vencidos los pavos de India"--"That does beat a Hindostan peacock"--exclaimed King Ferdinand, when Columbus introduced those most splendid products of the American tropics.
Nor can the exigencies of protection have evolved the glaring colors of the West Indian hornbill. The _toco_ (toucan), as the Cubans call the yellow-billed species, can be descried from a distance of two hundred yards, and is, indeed, not anxious to be admired at close range. Old specimens get as wary as mountain ravens, but, like crows, become ridiculously tame in captivity, and will follow their proprietors with loud croaks, every now and then opening their lunch-trap to indicate their desire for refreshment. They are, on the whole, the hardiest of all tropical birds, and can weather the winters of our coast towns as far north as Wilmington, in open-air cages, owing perhaps to their habit of extending their excursions to the high mountain ranges of their native land.
Economical Nature rarely wastes the gift of song on a bird of bright plumage, but it is less easy to understand why so many feathered beauties should have been afflicted with harsh and positively repulsive voices. The horrid screams of the peacocks, guinea hens, and macaws can hardly be supposed to charm their mates, and are too easily recognized to deter their natural enemies. But the roars (there is no more adequate word) of some species of hornbills would almost seem intended to serve the latter purpose.