But in many of the tropical forests there is not this convenient natural heat. Another method is employed. The birds take advantage of the heat generated by rotting vegetation. They scratch up the surface litter of the forest floor into mounds--structures that may be a yard or two high and five or six yards across. Some much larger have been observed. It is into these the hens burrow and lay their eggs. The temperatures in them have been recorded as 95° to 96° F., which compares with normal bird temperatures of just over 100° (bird temperatures are a few degrees higher than normal human temperature). The bush turkeys from Queensland have been bred in captivity, and have given some extremely interesting data, according to an article by Mr. Coles in the proceedings of the Zoological Society of London for 1937. It was the male who did all the building of the mound. Though the female started to cover the eggs laid singly in burrows in the mound, the male finished this. And it was the male that looked after the nest mound during the incubation period, continually scratching over the surface layer. Both parents helped the young emerge, by digging burrows into the mound which the emerging young, who had started to burrow out, could use. The young are in a very advanced state and apparently are able to fly and look after themselves upon emerging. On the day after hatching one chick is reported as able to flutter up to a perch six feet high. In the captive birds mentioned above, the parents, though they were attending to the mound and helped the chick out, appeared to take no further interest in the chick once it was out. There are a few other cases when birds cover or bury their eggs. With the grebes it has been said they covered them and left them to be incubated, but that is doubtful. Certainly the megapodes are the only ones to present a dear case of "artificial" incubation. This burying of eggs by the megapodes of course brings to mind the way some reptiles, such as turtles, bury their eggs. And considering that from an evolutionary viewpoint birds are really only modified reptiles, it is perhaps not surprising that they too have this habit. But that it is really an ancestral trait retained by the megapodes is doubtful. Rather I'm inclined to think it's another example of the many ways birds have evolved, or changed their habits so as to utilize as much of the environment as they can in as many ways as possible. CORMORANT FISHING [Illustration] In western Europe, when falconry was in favor for taking game on land and in the air, there was a certain vogue for training cormorants to take fish. Like the falcons, the cormorants were hooded and carried on the wrist, but of course where the falcons flew to their game, the cormorants swam to theirs.