Funck, who also visited the cavern above described, states that the Guacheros leave their nests after darkness has completely closed in, and that their harsh, raven-like cry may then be heard as they fly about in quest of food. Fruit forms their usual nourishment, and this they will swallow, even if as large as a Pigeon's egg; but the seeds and kernels they reject as indigestible. The nest is constructed of clay, and the brood consists of from two to four eggs. Grosz also gives an account very similar to that of Humboldt respecting another stronghold of the Oil Birds, called the Ravine of Iconongo, that he visited in New Granada. This extensive nesting-place is about half a mile long, and from thirty to forty feet broad, and had to be entered by means of a rope let down from above. Grosz fortunately succeeded in obtaining many Guacheros, both dead and alive, and made valuable observations relative to their demeanour and habits. Their movements in the air, he tells us, are light and rapid, the pinions and tail during their flight being held fully expanded; upon the ground their gait is extremely awkward, their feet requiring assistance from the wings, even to sustain the creeping hobbling motion to which their progress when on _terra firma_ is restricted. Whilst thus attempting to walk the tail is slightly raised, and the head and neck bent forward in a constant succession of serpent-like movements, in order to maintain their balance. When perched they keep the body erect, supporting it slightly upon the wings, and hang the head droopingly. If much excited whilst in flight, the cry of the Guachero becomes positively unearthly, so dismally hideous are its tones. Both parents brood alternately upon the eggs, which, according to Grosz, are white and pear-shaped. No preparations whatever are made for the reception of the young family, the eggs being merely deposited in the clefts of the rocks. The nestlings, when first hatched, are extremely ugly and uncouth, and completely helpless until they are fully fledged; so extraordinarily voracious are they that, if other food is not on the spot, they will fall furiously upon each other, or even seize and drag at their own feet or wings. * * * * *