WAYS OF THE WILD.

Auckland Star, Volume LXIV, Issue 117, 20 May 1933, Page 1 (Supplement)

WAYS OF THE WILD.

BIRDS' FEET.

DIVERSITY OF FORMS

(By A. T. PYCROFT.)

Mr. Tom Shout, of Raetihi, lias sent mo three birds' feet, whieli he asks me to identify. Mr. Shout says that two of them are apparently the feet of sparrow hawks, but they are so different in size and colour that there appears room for doubt. Tlio third foot which Mr. Shout sent me is quite distinct from the other two and is that of a bird which he informs mc he found embedded in the ice of Mangaehuehu glacier on Mount Ruapeku. Mr. Shout states that the glacier is to-day possibly much less than it has been for years, and as the bird from which the foot was obtained was embedded in the ice it may have been there for years. The bird was something liko a godwit and was about as large in the body as a pigeon, perhaps smaller, and it had a whitish grey breast. The back and wings were dark, and the beak was upwards of an inch long. Mr. Shout is correct in assuming that two • of the feet arc those of the bush or sparrow hawk. • The difference in size and colour is due to sex and age. The female bush hawk is usually a larger bird than the male. Many people in New Zealand are familiar with a large bird usually called a hawk, but which ornithologists call a harrier. New Zealand's true hawk, the bush hawk, often called the sparrow hawk, belongs to the order Ealconiformcs, and to the genus, that is, the assemblage of specics, known as falcons. The harrier is a member of the same order, but belongs to the genus Circus, of which there are about 15 species found in most parts of the world. The falcons, of which there are about 25 species, are distributed over the world except Polynesia. The question as to whether there is more than one specics of hawk in New Zealand has not yet been fully established. Oliver in- his book "New Zealand Birds" admits only one species, the bush hawk, and states that it is properly a falcon but is better known as the bush hawk, of which there are apparently two forms, differing only in size. There are no specimens in museums or published records of paired birds sufficient to give definitions of these forms even in terms of size. The few instances of paired birds available indicates that the Large males pair with the large females and the small males with the small females. The White-headed Stilt. The third foot sent by Sir. Shout is quite different from that of the birds of prey. It is a typical wader's foot, and a comparison with the feet of the white-headed stilt and the description of the bird given by Mr. Shout identifies tlie bird found by him to be a white-headed stilt. We find, in the waders that in some families tlie toes may be webbed, or partially webbed, and fully webbed in one family, the Avocets. Stilts' third and fourth toes are united at their bases by a membrane. The plumage is usually of a pied or grey colouring, and there is absence of a distinct breeding dress. Stilts derive their name from the extreme elongation of their slender legs, and are specially distinguished by the length of the metatarsus, which is equal to or greater than that of the long, slender, and, nearly straight beak; by the absence of the first toe, the slight webbing of the front toes, and the black plumage of the upper parts. The wings of these birds are long and pointed, with the first quill the longest. The tail is rounded, a large portion of the tibia is bare, and the beak is slightly curved upwards at the point with the nostrils at the sides of its base slit-like in form. The genus includes six or seven species, distributed over Southern Europe and Asia, Africa, Australia, and a considerable part of America, although wanting in Che northern regions of that continent, stilts are essentially marsh birds, although they always keep to open water, in which they may be seen standing up to their knees on the lookout for insects, molluscs, tadpoles, and so forth, their favourite resorts being lagoons where the water is brackish. They are generally found in small parties, and whether on land, in the water, or in the air, are remarkable for their graceful appearance. They walk with a deliberate step, which may be quickened into a run, and they fly straight but slowly with the neck outstretched and the long legs extended beyond the tail. New Zealand possesses two stilts, the white-headed and the black. The former is generally distributed in the North and South Islands, on the coast and inland, from the far north to the Waikato and East Cape southwards. The black stilt is found in both the North and South Islands, but is not common.

Mode of Life Indicated by Feet. Tho great diversity of form in birds' feet often indicates their mode of life. If birds are separated into two great orders, the flying birds and running birds, there will still be a great diversity of form in either order. Sea birds' feet, excepting those of certain penguins, gulls, and terns, are not adapted for walking, and in most sea birds tho feet aro used for swimming. Some sea birds, tho cormorants, or shags, sometimes use their wings as well as their feet for propulsion under water. Penguins use their feet as a rudder, the flippers being used for propulsion. The grebes, of which New Zealand possesses two species, have feet eminently suited for speed in swimming. The toes are lobatcd, that is, they have lobes, or membranous flaps, 011 tho sides of tho toes. The pukeko or swam]) lien is provided with long toes enabling it to walk with ease over swampy ground. lis food, which consists of soft shoots and roots of water plants, is held up to its beak with one foot as members of tho parrot order do. One of the obvious external characteristic* of the parrot family is that the fourth toe is permanently turned backwards, and. as tl.o first toe lias likewise a similar direction, tho whole foot is divided into a trout and back portion, each comprising two digits. Some of the imwis Jnid tour toc* 011 each foot and others three, but all differed from other birds of the oulci, which inWlilcs the ostiK-hs, lheas, cassowaries, emus, and k.wis. ... having 1 .-v over tiie iui tho exterior tendons of the tibia. _ M ° as aro therefore not so highly specialised.