[Illustration: FIG. 155. (D) FEMALE HOATZIN CROUCHING TO AVOID OBSERVATION.] Of all my pictures that of Fig. 157 is the prize. We came upon a flock of Hoatzins late in the afternoon and were fortunate enough to get into a clear space and to photograph eleven on the same plate; the confused mass near the centre of the picture containing four individuals. Fig. 148 shows the character of the country where we found the Hoatzins on Abary River, with the line of dense growth on one side and the level savanna on the other. A study of an individual pair of birds is given in Figs. 152 to 156, and the actions of these two birds were so typical of Hoatzins that an account of them will apply to the species in general. I made these photographs from a boat, standing on the thwarts while Milady guided it through the brush. We flushed the female from her nest (marked by a circle in Fig. 150) and she flew to a branch some eight feet higher (Fig. 152). The male then appeared from a tree beyond (centre of Fig. 152). We remained perfectly quiet, and the next photograph shows her tail-on, looking about, while the male, who has flown nearer, is watching us suspiciously. Fig. 154 shows the male on another perch, still more alarmed, and a moment later he thrashed his way out of sight. Meanwhile the female had rediscovered us and crouched down (Fig. 155) hoping to avoid observation, but as we pushed closer to the nest, she rose on her perch, spread tail and wings to the widest (Fig. 156), her scarlet eyes flashing, and uttering a last despairing hiss, launched out for a few yards. At this moment, as may be seen in the same picture, a second pair of birds left their nest in the next clump of undergrowth and raised their discordant notes in protest at our intrusion. The assertion which we made last year—Milady having been the first to observe it—that Hoatzins use their primaries as fingers, in the same way that the chicks and partly grown young use their wing claws, has been received with some doubt, and I am glad to offer a photograph (Fig. 156) as evidence. In the right wing of the Hoatzin, the thumb feathers are plainly visible, with their inner edges fretted away, while the first six primaries also show signs of severe wear, such as would be expected from the rough usage to which they are put. Attention is called to the apparent immobility of the crest, which is as fully erect in the crouching Hoatzin (Fig. 155) as in the same bird a minute or two later, alert and about to fly (Fig. 156). Thus it was that we took the first photographs ever made of these most interesting birds. [Illustration: FIG. 156. (E) FEMALE HOATZIN TAKING FLIGHT, WITH WINGS FULLY SPREAD; A SECOND PAIR OF BIRDS LEAVING THEIR NEST, IN THE BACKGROUND.]