IN TOUCH WITH NATURE

Otago Witness, Issue 3613, 12 June 1923, Page 7

IN TOUCH WITH NATURE

By

J. Drummond, F.L.S., F.Z.S.

The harrier hawk's services in respect to the rabbit nuisance are demonstrated to some extent by Mr O. Caldwell, Apiti, Pohangimv County, Wellington Province. Last spring he found a harrier’s nest in a very dense swamp near his home. Apparently, the young were fed exclusively cn young rabbits, as many remains of rabbits were found about lf;e nest after the young birds had flown away. Mr Caldwell adds: “These hawks do net trouble much about comfortable nests—just a few leaves of the bull rush and grass. I think that it is unusual to find harriers’ nests. I am past 77 years, and this is ony the second one I have found in 70 years, and have been all my life in the wild parts of New Zealand, and have taken a deep interest in native birds ever since I settled down to farming here 25 years ago. I never lose touch with cur bird friends but in the past they were present in unlimited numbers —bellbirds, tuis, parrakeets. and ducks in thousands. I have seen thousands of parrakeets in flecks in Maori cornfields.’’ “On May 4, which seemed to be a summer day in every sense, I heard a cicada singing to its heart's content,” a Takanini, Manuka;! County, correspondent writes. “I never heard a cicada sing in May before, and I think that it must be unusual. I do not know if it sang all day, but I heard it for some time in the morning. It will be interesting to know if any other correspondents have had the same experience.” The same correspondent corroborates Mr Cadwell s evidence in the harrier hawk’s favour: “H hen I was travelling to town by train, as the train was leaving Southdown. I saw a hawk rising from ra.upo in a swamp. It had a large rat in its bill. The rat had been <eized by its head, and its tail was hanging down. The hawk, flying over the train, alighted on. the other side with its prey, but as the train had gathered speed I did not witness the result.” Scent-producing organs possessed by some male butterflies for the purpose of artractlng females cf the same species -are the objects of investigations made by Mr G. V. Hudson, a Wellington entomologist, who has studied New Zealand insects for many years. Attention first was directed to those organs by Fritz Muller almost 50 years ago. He emphasised their significance in connection with Darwin’s theory of sexual selection, which then was gaining ground steadily. Mr Hudson has found in New Zealand several good illustrations of scentproducing organs. Males of a strongflying. widely-ranging butterfly. Dana id a plexippus, have a pocket-like structure on the liind wing, which, Mr Hudson believes, is a scent-producing organ. Males of a beautiful New Zealand moss-green morh. Erana grair.inosa, have a large fold on the edge of the fore wings, which conceals a tuft of long pink hairs. The hairs when stirred with a pin emit a very agreeable perfume, resembling vanilla. Mr Hudson states: “A remarkable lobe in the liind wing of males of e. curious genus of New Zealand butterflies, Tatosonia, is a pocket-like organ which, in the absence of anv evidence to the contrary, must be regarded as scent-producing Males of Declana leptomera have large tufts of hairs on the tipiaa of the hind legs. Similar tufts are found amongst some of our smaller lepidoptera. It is almost certain that these structures are for the purpose of emitting perfumes agreeable to the females. Many observations have been made on scent organs and scent; omitted bv tropical butterflies and the use of those special structures hv males, to attract females, has been placed practically beyond a doubt. At the same. time, it must- I>. remembered that roomhSas of some specie? of butterflies emit disagreeable odours, which protect them from the attack? of birds and of other enemies, but in those cases the scent emitting power is net confined to the males. In a fair number of our moths there are considerable differences in the colours and the markings of the sexes, but, except in a few dav-flying moihs, the males are not more brilliant or more beautiful than the females. In one species the sexes are almost identical in colour, but have very different markings. The sexes of two beautiful forest-dwelling moths differ in dze. colour, and outline. In a brilliant dav-flying species, which almost certainly mimics a distasteful snacies belonging to another genus, the males are much more brilliantly coloured ihan the females, and this certainly is due to the operation of sexual selection. “New Zealand’s largest member of the lepidoptera, TTepialis vireseens, shows striking sexual differences in the outlines of the wings, the colours, and the markings. The general colouring of both sexes of that species is equally protective when (he moths are resting amongst foliage, but the colour-

ing of the male probably is more beautiful, certainly is brighter, than that of the female, and it may have arisen through sexual selection.” Mr Hudson adds: “Experiments have been made to discover the means by which male lepidoptera find females that are far away from them. The theory that they track by scent is not a satisfactory explanation. There seems to be little doubt that the mysterious faculty is located in the heavily branched antennae, and that seme sort of communication is set up in the nature of wireless telegraphy.”