A short distance beyond I encountered what I found later was the most common assemblage of birds to be found in this region—a flock of Antbirds and Woodhewers, with a few other species, such as Flycatchers and Tanagers. One could not take even a short walk in the forest hereabouts without observing several such flocks, numbering from a dozen to fifty or more individuals. The Antbirds comprise a family, _Formicariidae_, of which more than two hundred and fifty species are known. They are rather generalized passerine birds, which are found only in the tropical forests of northern South America. Inconspicuous in color and retiring in habits it is only when one becomes familiar with these tropical jungles that one realizes how numerous these birds really are. Their notes are usually uttered only at intervals and are often difficult to locate. They creep silently among the lower branches or, as we have seen, search the ground for the insects which form their food. The name Ant-thrush is rather a misnomer, for they are not Thrushes, and while they are always attendant upon the swarms of hunting ants yet they seldom feed upon the ants themselves, but on the insects stirred up by the ferocious insects. We know but little about the nesting habits of these birds, and we were unable to locate a nest during our brief stay although we knew that several were breeding near the clearing. Like most other tropical families, Antbirds have been compelled by competition to specialize, and we find some Shrike-like in habits as well as appearance; others resembling the long-legged Pittas of the East Indies, while the majority parallel Wrens, Warblers or Thrushes. The Woodhewers of the well-named family _Dendrocolaptidae_, or Tree-chisellers, form with the Antbirds a considerable percentage of the smaller forest birds of this region. There are not far from three hundred forms of these birds, all of dull colors—rufous or brown tones prevailing. Woodhewers in the main parallel the Woodpeckers, and especially the Brown Creepers, in their method of obtaining food. Their claws and feet are strong, the legs short, and the tail feathers in the majority of species are stiff and spine-like. They hitch up the trunks of trees, finding their food in the chinks and crevices of bark, but not boring into the wood like Woodpeckers. While the stiff tails show that all have probably descended from tree-creeping ancestors, some Woodhewers have deserted the trunks and have become Warbler-like in haunt and habit. Such a one is the Cinnamon Spine-tail[94] or “Rootie” (p. 379). In the tropical forest however, Woodhewers differ but little in their method of locomotion, and one or more of these fox-colored birds hitching up a great trunk is one of the commonest sights. There is remarkable adaptiveness in the bills, some being stout and blunt, others long and curved.