July J COOPER, 53 1971 Unusual Behaviour of the Musk Duck by Roy P. Cooper, Melbourne The Musk Duck, Biziura lobata, is seen usually as a low silhouette, floating motionless on the surface of the water, far from the shore. Seldom will they be observed close to the edge of a lake or swamp, as they immediately dive, and swim very fast underwater, at the approach of man. The swims so low in the water that it can dive without any noticeable disturbance of the surface, and the observer is usually unaware of the proximity of the duck until it emerges some distance out on the lake. Most members of the , the family which contains the ducks, geese and , become tame when they are unmolested and fed by man. T his particularly applies to many, but not all , of the European countries, especially E ngland and Spain, where the rivers, lakes and ponds are used each year as stop-over places for the migrating waterbirds. In addition to protection, the are fed, if not by the local authorities, then by the public. Two years ago, in Tokyo, Japan, the migrating ducks, returning to their breeding grounds in northern Asia, were caught in an exceptionally late snowfall. T he lakes had partly frozen and the birds could not continue northward until the weather became warmer. Much food had been put out and the birds were very tame, and were easily photographed. In A ustralia. when the same conditions and protection are granted, we find the same reactions from the ducks. T his not onl y applies to the common species, Black Duck, White-eyed Duck, both species of teal, Black Swans etc., but also to the rarer forms, Blue-billed, Freckled and Pink-eared Ducks. However, the one species that I have never seen taking food in this manner is the Musk Duck. It will be seen, usually, well out on the lake, or on an open-water swamp. Should it come near other birds that are being fed it will remain on the outskirts of the group and not venture into the feeding area. Of course, there is always the exception, but I have had to wait for over thirty years to find it. During this period I have seen many thousand s of Musk Ducks, and they have all behaved in a manner that would indicate that they are severely persecuted. This is surprising as they are not shot at by sportsmen, although they would be disturbed by the roar of the guns during the " duck season". They are unpalatable to humans, as the musky odour, which is a sex characteristic and confined to the male bird, is very strong. One of the early visitors to these shores stated that the bird "smelt so intolerably of musk that it scented nearly the whole ship". On November 1, 1970, when returning from Horsham, I stopped on the banks of Lake Wendouree, at Ballarat, Victoria, to see what waterbirds were present. Black Swans were very plentiful, and many birds were accompanied by cygnets of varying ages. 54 COOPER, Musk Duck [ Bird Watcher

Driving slowly around the shores of the lake I came to an area where the Sunday afternoon visitors were throwing bread, biscuits or other tit-bits to the birds. Black Swans crowded the area, keeping most of the ducks and away, and seeing that their cygnets received their share of the food. I was surprised to see behind the Swans, at a distance of Jess than one hundred yards from the shore, a Great Crested , cristatus, swimming slowly backwards and forwards, but making no attempt to come closer. At another place, on the edge of the lake, I was photographing a pair of Swans with their cygnets when, suddenly, a Musk Duck zoomed up from underneath one of the Swans and grabbed a piece of bread from amongst the cygnets. The bird swam so fast, and came up from under the so rapidly to snatch the food almost from the of the cygnets, that the action can only be described as "zooming". I was not even aware that there was a Musk Duck in the vicinity, and it must have swam for some distance under the water. The bird had surfaced after taking the food , but it dived almost immediately and I could not locate it again. Apparently, it hid amongst near-by vegetation. Some fifteen minutes later, and one hundred yards further along the bank, I saw two children attacking a Musk Duck with sticks. The bird was only five to six feet from the bank but, fortunately, this was too far for it to be harmed by the children. The duck moved out to approximately thirty feet from the bank, and swam strongly and swiftly, on the surface of the water, parallel to the shore. After following it for two hundred yards I was stopped by a fence, but the duck continued onward, still keep­ ing the same distance from the bank. I continued to drive around the lake and shortly came to a place where the birds were being fed by many visitors. The Black Swans were very numerous and would come out of the water and take the food from the hands of the picnickers. There were several hundred Swans and many other waterbirds present, and they were spread out along the edge of the bank for over two hundred yards, being fed by different groups of people. On the outskirts of the feeding birds, 75 to 100 yards from the shore, there were five Musk Ducks, two males and three females, but they appeared to be satisfied to remain quietly on the surface of the water, and did not make any move toward the land. l .. fter watching the Swans for some ten minutes a sudden com­ motion among a small group of birds attracted my attention, and I was amazed to see a male Musk Duck competing with the other birds for the food that was being thrown to them. It was no more than 20 feet from the shore, and appeared to be unafraid of the people. There was only one male bird left out on the lake so, apparently, this was the second bird. The food of the Musk Duck has been analysed from stomach contents as being "almost entirely of origin". Yet, on The speed at which the Musk Duck swims can be gauged by the size of the waves; also the ripples that are created in front of the bird. The large pendulous lobe is used to cut through the water. Plate 14 Photo hy R oy P. Cooper

this Jake, the bird was eating bread, biscuits, cakes or whatever other food was thrown to it. I began to feed the duck and within minutes it had come to within a few feet of where I was stand in g. Its method of obtaining the food was unusual, but very positive. If it had more than three feet to travel it would dive and come up underneath the tit-bit, and snatch it in a manner that was similar to the action of a fish. Seldom would the duck swim more than a few feet on the surface of the water. So fast did it swim under the water that I calculated that if the duck had 15 feet to swim to reach the food and a swan only five feet, then the duck would be successful every time. Occasionally the Swan would be reaching for the food when, sud ­ denly, the duck would snatch it almost from the opened bill, much to the obvious surprise and fright of the Swan. It was evident that the duck could swim much faster under the water, using both feet and wings, than on the surface, where the feet onl y were used. By careful feeding and patience I led the Musk Duck away from the other birds, and, finally, was able to take as many photo­ graphs as I desired. At the beginning I missed out by having too large a telephoto lens on the camera, and l had to return to the car for another lens. T hen the procedure of enticing the duck away from the other birds had to be repeated. Even when the bird was alone, if it had more than three feet to travel it would dive and come up under the food . 56 HINDWOOD, [ Bird Watcher

Only the one Musk Duck came to feed; the other four birds remained in the same position as they were when they were first seen. Although I have observed the display of many Musk Ducks, it has always been from a considerable distance. On September 27, 1970, I was sitting in a car some 30 to 40 feet from the edge of a lake, in northern Victoria, when a male Musk Duck suddenly appeared in a small area of cleared water. Reeds were growing in the water for a distance of some 30 feet from the shore, but they were not dense, and Coots, Fulica atra, were swimming freely among them. There were many pairs of Musk Duck on the lake, and some of them were displaying. The cleared area where the Musk Duck had so unexpectedly appeared was no more than five feet across, but being open to the shore it enabled me to have a clear view of the display. The pendulous lobe suspended under the lower mandible was much enlarged. The bird was crouched low in the water and the head was held back, allowing the lobe to just touch the water. The tail were fanned out and erected over the back, giving the appearance of a mass of erect bristles. Every few second s the bird would kick with its feet, the sound being like a dull "plonk". This leg action was clearly seen by us, with the aid of 8 x 30 field-glasses, and the sound was caused by the kick, not by the throat of the bird. However, as the kick was downward no forward or backward movement occurred; the bird remaining in the same position. This action was continued for some minutes, although no female Musk Duck was seen in the vicinity. Unfortunately, a movement on my part caused the bird to dive and it was not seen again.

Notes on the Cattle Egret By K. A. HINDWOOD, Sydney Cattle Egrets, Ardeola ibis, were liberated near Derby, north­ western Australia, in 1933; the number set free was eighteen ( Serventy & Whit tell, 1948 ). In recent years the species has spread throughout Australia, ranging to all southern States and to Tasmania. It has also reached New Zealand, more than 1,000 miles east of the Australian continent. Following their release no Cattle Egrets were reported until 1948. In that year H . G. Deignan (1964) noted hundreds "if not thousands" in the Oenpelli District, Arnhem Land. Whether the considerable numbers then present in the Northern Territory had descended from the few set free in 1933, or were from self-intro­ duced immigrants of an earlier, and perhaps later, period is a matter that was discussed by J. M. Hewitt (1960) in 1960. A rookery of Cattle Egrets on the Adelaide River, Northern Terri-