322 NATURAL HISTORY. 



" During gloomy weather it is often very active ; and sometimes even in the bright sunshine a 

 score of them may be seen together, flying and circling about high above the tree-tops, uttering their 

 loud screams, and apparently bent on convivial amusement. When the shades of evening bring a 

 deeper gloom into the depths of the forest, and all sounds are hushed, save the low hoot of the waking 

 Morepork, or the occasional cheep-cheep of the startled Robin, the Kaka becomes more animated. It 

 may then be heard calling to its fellows in a harsh rasping note, something like the syllables ' t-chrut, 

 t-chrut,' or indulging in a clear musical whistle with a short refrain. It is strictly arboreal in its habits, 

 and subsists to a large extent on insects and their larvse, so that it is probably one of our most useful 

 species. Where they exist in large numbers they must act very beneficially on the timber forests ; for 

 in the domain of Nature important results are often produced by apparently trivial agencies. Like all 

 the honey-eaters, while supplying their own wants, they do good service with their brush tongues by 

 fertilising the blossoms of various trees, and thus assisting in their propagation ; while, on the other 

 hand, the diligent search they prosecute, for insects and grubs, and the countless numbers daily 

 consumed by each individual, must materially affect the economy of the native woods. On this 

 latter point Mr. Potts has furnished the following valuable note : ' Although so often accused of 

 injuring trees by stripping down the bark, from careful observation we do not believe a flourishing 

 tree is ever damaged by its beak. It is the apparently vigorous, but really unsound, tree that is 

 attacked, already doomed by the presence of countless multitudes of insects of many varieties, of 

 which it is at once the food and refuge, either in their perfect or larval state. In the persevering 

 and laborious pursuit of this favourite food, the Kaka doubtless lends his assistance in hastening 

 the fall of decaying trees ; the loosened strips of bark dissevered admit to the exposed wood rain 

 and moisture collected from dews and mists, to be dried by evaporation by the heat of the sun, 

 by the desiccating winds, only to become saturated again. Under this alternation the insidious 

 fungi take root, decay rapidly sets in, the close-grained timber gives place to a soft spongy texture, 

 branches drop off', and gradually the once noble-looking tree succumbs to its fate ; but its gradual 

 decay and fall, the work of years, has proved beneficial to the surrounding plants : the dropping 

 of the branches admits light and air to the aspiring saplings, assists in checking the undue spread 

 of lichens and epiphytes ; and when the old stem falls, tottering down from its very rottenness, 

 its place is supplied by vigorous successors.' 



" In estimating the value of the labours of the Kaka as an insect-eater, it should not be for- 

 gotten that the family of Woodpeckers is entirely absent from our bird -fauna, and that upon this 

 indefatigable climber devolves some share of the duty of representing that peculiar group of 

 forest birds. How diligently the insects are sought for by the Kaka may be judged from the 

 heaps of bark chips that lie beneath the decaying trees. Often it may be noticed on the ground 

 tearing away the mossy clothing of the huge gnarled roots that spread around ; even the soft 

 rotten boughs are gnawed to obtain the larvse of some of the larger bush insects." 



The Nestors vary immensely in colour, so that many of the plumages now known to be only 

 occasional varieties have been supposed to be specifically distinct. They are birds of large size, and 

 have the cere, or fleshy portion at the base of the bill, rather strongly developed, the bill being large 

 and powerful. The colour is of an olivaceous brown, with a dash of dark red, the crown grey, and the 

 ear-coverts shaded with orange, the cheeks with dark red, as also are the lower back, rump, and 

 upper tail-coverts and abdomen. 



The structure of the bill of the Parrots is so remarkable as to be worthy of a more extended 

 description than could be given to it when it was incidentally referred to in our account of the 

 osteology of birds in general. The way, however, in which the upper and lower jaws are con- 

 nected with the skull was there explained, and a reference to the description on pp. 241-2 will 

 save the necessity of much repetition now. That account embraced all members of the class of 

 birds ; here we are dealing only with certain peculiar modifications. 



If the skull of an adult bird of any familiar type, such as a Crow, be examined, it will be seen 

 that the bones of the upper jaw are apparently continuous, and form one piece, with those of 

 the forehead and sides of the head. There is nothing that looks like a joint, or " articulation," 

 between the bill where it is attached to the forehead above, or to the long jxigal arch ( " quadrato- 

 jugal ") that runs each side to reach the quadrate bone, or to the flattened bones that help to 



