Courtship Ceremonies

New Zealand Herald, Volume LXXIV, Issue 22909, 11 December 1937, Page 14 (Supplement)

Courtship Ceremonies

Habits of the Great Crested Grebe Specially Written for the New Zealand Herald by R. A. FALLA, M.A.

THE sport and recreation of flyfishing takes many people to the shores of lakes and streams at this time of year, and the leisurely opportunities for observing plants and animals make many good anglers also good naturalists. CHANOES MISSED

Published accounts of the crested jjrebo in New Zealand are scrappy an" barely sufficient to piece together the elementary facts of its lite history. .But as the species is almost cosmopolitan a great deal is known from observations made elsewhere; indeed, in Great Britain the crested grebe is almost the most-fully-studied of the much-studied British birds. As the grebe is a poor flier, the isolation, of the various geographic units of this widely-scat-tered species must have existed tor ages. Nevertheless, so fixed is the pattern of habit in birds that the smallest details of its behaviour seem to be the same everywhere. To say that "be-haviour-pattern" may be more fixed than plumage pattern is to enunciate a theory that has much evidence to support it. NESTING PLACES Crested grebes' nests are built in vegetation overhanging water, or actually floating in the water, moored. Occasionally they arc on dry land. The nesting material is weed brought up from tho lake-bottom, and on account of the situation of the nest it often remains extraordinarily wet. From three to five eggs are laid; I have seen live, but Mr. E. F. Stead informs me that four is more usual in his experience. Young grebes leave the nest soon

There must still be a few, however, who are missing the chance of making their recreation as enjoyable as it coukl be and of finding some compensation for the inevitable delays and disappointments associated with trout fishing. I met one such recently on the shores of a. South Island lake, and as neither of us knew the other our conversation can bo reported quite impersonally. RICH PLUMAGE

A great crested grebe, probably the most ornamental of our native waterfowl, was sitting on a nest of w£eds at the edge of the lake, and her mate, swimming anxiously near, was giving a good display of his rich and striking plumage. A remark to my chance ac-

quaintance on the beauty of tbe group brought the reply, "Oh, yes; but they're no use—not a sporting bird, and they clean up a lot of trout." It should be said that he had no intention of disturbing the birds; but his attitude of indifference to their points, and slight grievance at thdir supposed feeding habits, is not removed as far as it should be in 1937 from the days when tho crested grebe was more actively persecuted. VANDALISM AND IGNORANCE In tho early days of settlement feminine fashions made grebe hunting popular and profitable. Writing of a lifetime of observation in South Westland. the late Charles Douglas said that at one time the birds were almost exterminated in country that had been opened up. According to his account they increased gradually under legal protection until another war was declared in order to protect introduced trout fry from their alleged depredations. Now they are again on the protected list, and in danger only from occasional vandalism and ignorauce. They may be seen on lakes throughout the South Island, but are certainly, very rare in the North, where the little grebe or dabchick holds its own much better. HEAD PLUMES Apart from its larger size the crested grebe differs from the dabchick in tho ornamental head plumes that adorn both sexes. The crest from which the bird takes its name consists of black ear-tufts and a ruff of which the upper part is white, then vivid chestnut, deepening gradually to glossy black. For the rest, the plumage is blackish brown above and white below, the close-fitting body plumage having the appearance of satin. With its lobe-toed feet set well aft the bird has all the essential structure of a diver. On land it is the most awkward of all aquatic birds; its normal attitude of repose is an easy swimming position with neck erect.

after hatching. They swim well and can take rest or shelter perched on the backs of the old birds. As they reach maturity they must move off to fresh haunts, as pairs in the nesting season seem exclusive in the matter of territory. "DUNDREARY ATTITUDE" The study of the courtship ceremonies of tiie crested grebe made more than twenty years ago by Julian Huxley was one of the narliesf. of a series that has since set a new standard in scientific ornithology. He found that certain attitudes and actions occurred so regularly that they could be exactly defined. One frequent attitude he called "shaking," a frequent pose the "Dundreary attitude," and so on. Thus the "penguin-dance" is described as the gradual converging of two birds until their breasts touch, after which the continued paddling with the feet forces the two bodies, balanced against each other, almost out of the water. The two then gradually subside backwards to their original swimming positions. *\ll these actions and more are in the nature of ritual performances associated with mating, and it is significant that in crested grebes, of which both sexes are equally decorative, the displays are equally reciprocal. The Darwinian theory of sexual selection based on a consideration of briglitly-plumaged males and drab females must be modified to meet such a case. CENBUS-TAKINQ Another modern study in which the crested grebe has figured is that of bird census-taking. In" 1931 a complete census of the species was taken in Great Britain, and about 1240 species were found in England, Scotland, and Wales. From a sample count taken in 1935 it was estimated that there had been a decrease of 6 per cent in breeding pairs, and an increase of 78 per cent in non-breeding birds. The actual results are of less significance than the fact that it has been shown to be possible to make a tally of wild birds and to record their fluctuations exactly without having to depend on mere opinion as to their welfare.