Birds were not particularly plentiful in the forest. There were, however, a number of interesting forms, particularly among the tanagers. One species (_Psittospiza riefferi_) was about the size of a robin and of a deep grass-green color, with a chestnut-colored face and abdomen; these birds live singly and in pairs in the tall trees and are of a wary disposition. Another tanager (_Sporathraupis_) has a bright-blue head and olive-green back; the breast is deep, dull blue merging into golden yellow on the legs. The natives called this bird _jilguero_, a name applied to the solitaire in other localities. It lives in the lower branches of trees, travelling in pairs or small flocks and feeds on fruit; the song is not unpleasant, but cannot compare with any solitaire known to me.
While collecting one morning my attention was attracted by a chorus of chirps and screams, and following up the sounds I reached a tall tree where a peculiar bird drama was being staged. A number of California woodpeckers (_Melanerpes flavigularis_) had drilled numerous holes in the tree-trunk, from which sap trickled in small streams. A dozen or more buff-tailed hummers (_Boissonneaua flavescens_) had apparently come for their daily jag, for the sap very evidently had an intoxicating effect. Arriving in a bee-line, newcomers landed against the trunk, where they clung like so many moths, the buff-colored tail spread wide and against the bark for support. Their antics as the different stages of hilarity were reached were most amusing. They twittered, fought, turned, and tumbled in the air; others dozed on small twigs, and several fluttered toward the ground in an exhausted condition. This performance continued daily for a week, until the sap suddenly ceased to flow; then the tree was deserted and silent, the capricious band having no doubt sobered up from their debauch and gone back to their normal and more profitable pursuits in life.
In getting water from the brook, one of our men discovered a narrow trail under a giant log. We justly surmised that animals of some sort used the runway in journeying to and from the water. A trap was set in the path, and next morning a fine white opossum of large size had been safely ensnared. In the days that followed we secured an even dozen of the animals. They proved to be a form unknown to science that now bears the name _Didelphis paraguayensis andina_. The cook said that they were delicious eating, and prepared for us an unusually fat individual; but we found the meat of rather strong flavor, and not very palatable. A solitary weasel (_Mustela affinis costaricensis_) was also taken in the same spot. It would be interesting to know whether this animal came down to drink, or was in pursuit of some of the other creatures that frequented the runway. Weasels are courageous, active, and bloodthirsty little animals; their eyesight is poor, but their sense of smell is keen and they will tirelessly follow their intended victim until it falls into their clutches. I have frequently heard that they attack and kill small deer by clinging to the neck and doggedly chewing their way through the skin until the jugular vein is severed; this does not seem probable to me, however, and it is far more reasonable to believe that rats, mice, frogs, and other small creatures form the bulk of their prey. On account of their slender proportions, they can trail the quarry through small holes and crevices; in addition, they are also expert climbers. On one occasion, while “squeaking” to attract a bird, a weasel came instead, looking for the supposed helpless creature, and ran over my feet without suspecting the fraud.