Page:The Emu volume 18.djvu/326

 of the female. Fish seemed abundant everywhere, and my boatman caught a good many crayfish.

Pandion leucocephalus. White-headed Osprey.—This fine species is the most prominent bird of prey inhabiting Dampier Archipelago. Few islands are without a pair, and some of the larger islands, like Fortescue Island or Sholl Island, possess as many as three occupied eyries. As a general rule the large, massive nests are placed on rocks or on low sand-hills immediately above the high spring-tide line. On some islands a few stunted and very woody bushes grow immediately on the inner side of the sand-hills. It should here be noted that most of the islands are saucer-shaped, and in the hollow interior vegetation is more prolific than on the surrounding sand-hills. Ospreys not infrequently pile their huge nests on the tops of these bushes. In one or two instances I found nests built on the ground in the interior of an island. All were very elaborately constructed of sticks, seaweed, and sponges. Very often a piece of deal or other soft wood was added. Near Legendre Island I saw an Osprey staggering along with a stick that must have been four feet long, and fairly thick in proportion; it was just about as much as the bird could manage. The majority of the nests appeared like the work of several seasons, and, being constantly added to, attained a height of three feet or more. The top of the pile, on which the eggs rest, was always flat, and composed of a cushion of brown seaweed and small pieces of sponge, with fragments of coral and shells. The eggs varied from one to three, and in the latter case a considerable time seemed to elapse between the laying of the first and last egg. It might be thought that such richly-marked eggs would be conspicuous in the nest. This is far from the case, the rich chocolate markings on a white background harmonizing very well with the brown seaweed and bits of broken shell or coral usually found in the nests. Generally one of the parent birds watches near the nest, even before the eggs are laid; but it is never left unguarded once the female has begun to lay. On landing near a nest, one or both parents fly to meet the intruder, uttering querulous whistling notes whilst hovering overhead. If the nest contains eggs both birds fly anxiously about. After a little experience one knows pretty well where to search from watching the flight of the parents. All avian intruders, especially Sea-Eagles, are jealously driven from the neighbourhood of the nest. The female is not a close sitter, and leaves the nest often before it can be detected. On the extensive Barrow Island, which has a coastline of over 40 miles, Ospreys are not plentiful; but on the neighbouring Double Island, which is simply an island of steep, conical sand-hills with occasional flats clothed with snake-wood and other vegetation, three or four pairs were nesting. Some of these conical sand-hills were clothed with a species of convolvulus, locally called "shore-runner," right up to their summits; and in several cases Ospreys had wisely chosen these particular sand-hills for nesting-sites. The growth of convolvulus did much towards making the nest inconspicuous; one was so well concealed as to be only revealed by observing the sitting bird spring from the nest some distance away. A pair of Ospreys I had under observation on an islet not a quarter of a mile from my camp at Barrow Island behaved in a very erratic manner. I first noticed them continually bringing building material to an old nest in a solitary mangrove. After much labour had been expended they suddenly started to repair an old nest in the sand-hills