Harteman Wildfowl - Pink-eared duck in captivity

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Pink-eared duck in captivity

By Tom Spence, Perth Zoo

This story was written by Tom Spence, Perth Zoo director from 1967-1984.

It was shared with us by Trevor Andersen, Australian Avifauna in 2015.

This droll little duck which is found only in Australia has rarely been kept in captivity. Although Delacour notes in his monograph, (1. The Waterfowl of the World), - That the Pink-eared duck (Malacorhynchus membranaceus) has been kept by certain Australian zoo’s, I doubt this. However, Frith (2) and his team maintained several pairs at the C.S.I.R.O Field Station at Gungahlin years ago, where they lived under semi- natural conditions on a large pond. Frith also succeeded in hatching this species under conditions of artificial incubation but has made no claim to fully – rearing the ducklings. We have had considerable experience with this species in captivity in the Perth Zoo and I offer these notes which may help others to rear and maintain this attractive species.

We have succeeded with specimens acquired in three different ways; namely, hand –reared ducklings hatched from eggs taken from the wild, flightless young taken from the wild, and trapped or rocket-netted adults. In addition, two specimens have been received which have been injured during duck shooting. Our early attempts with all categories were unsuccessful and the reasons will be divulged in this report.

Eggs taken from the wild are easily hatched under standard artificial conditions after an incubation period of a little more than 26 days. The nests are easily found and their presence usually betrayed by the anxious parents attending in the vicinity and by the conspicuous and copious white down which is used to cushion and cover the eggs. In contrast with many other Australian waterfowl, the nests of the Pink Eared are not found in tree holes but are most commonly found in the crotches of paper-bark trees or flooded gums, invariably surrounded by water. I have found them in other sites quite commonly, including a hollow gate post, old nests of coots and Little Pied Shags, and even on the flattened nest of a babbler. Careful precautions must be taken in transporting the eggs, as with the eggs of other waterfowl. Not only must the eggs be protected from heat loss if the incubation has begun, but they must be carefully guarded from vibration. We wrap the eggs carefully but firmly in thick cotton wool which has been previously warmed by leaving it in the hot sunshine for some time and the eggs firmly placed in an insulated box. On all of the occasions when we have taken eggs, a companion has carried the box on his lap on the return journey to the Zoological Gardens. I believe this is necessary to reduce the jolting and vibration on country roads. We have successfully transported eggs over a distance of 200 km, both fresh and partly incubated and yet have had excellent hatchings, in some cases 100%. Naturally, before the egg hunting expedition is undertaken, the incubators should be in action and calibrated. We have used forced – draught incubators for the major part of the incubation, transferring the started eggs to a still air incubator until hatched. The newly- hatched young are returned to a drier atmosphere and are kept for some 24 hours in the drying box of the incubator and transferred to rearing boxes.

Experience has shown that solid walled rearing boxes about 1.0m x 0.65m x 0.3m are suitable. Sheet hessian or a clean hessian bag is laid on the floor with food dishes at one and a raised platform on the other. We find an upturned feeding dish suitable to achieve this elevation [see sketch]. Above the elevated end, a 275 watt inferred lamp is suspended at the height of some 45cms and adjusted as the ducklings grow. This arrangement of food dishes at one end and brooding area at the other keeps the ducklings dry. The ducklings are very messy indeed in their feeding behaviour and the hessian soon becomes saturated, making it necessary to change the hessian once a day. The breeding boxes have a frame mesh top and this is essential for the newly-hatched ducklings sometimes attempt to jump out. When a large brood has been hatched the young should be divided so that there are four ducklings per chamber; if more are accommodated together, they tend to climb upon one another and the down becomes fouled. Ducklings are kept in these rearing boxes until they are about four weeks old when the flank and mantle feathers are well developed. At that stage, if the weather is suitable, they are transferred to outside enclosed rearing runs of traditional type, made of mesh, with overhead cover and shelter. Because of their sensitive feet, it is essential that the ducklings are reared on a lawn and moved regularly to clean ground.

The food of the ducklings is critical. Our early attempts to rear ducklings by the traditional method of offering a gruel of turkey starter crumbs, invariably ended in failure, for the ducklings became impacted with the fibre content of the diet and died at 7-9 days. After several attempts with turkey starter, supply of live food was undertaken and the brood of six was successfully reared to maturity. This entailed a great amount of effort from zoo staff with twice daily collections of fresh water crustacea such as daphnia and larval Hemiptera. The supply of fresh water nekton is very erratic and dependant on wind and many other factors. Because of this unreliability, later attempts at rearing ducklings with live food failed, and unfortunately, broods of ducklings consequently died of starvation. However, at this stage the use of trout chow was investigated and proved to be highly successful. Indeed the last two broods, one of seven and one of six were fully reared on this substance alone without any live food even from the day of hatching. The trout food used was “Trout Starter, grade 3 c, the crumb size being suitable for newly hatched ducklings. For the first few days, small feeding dishes, only about 1.5cm deep and only small amounts of trout starter sprinkled on the surface. Once the ducklings have found the food source and can negotiate the rim of the feeder, shallow baking dishes about 20x30 cm and about 3cm deep are substituted. The feeding dishes must be placed at the end away from the heating lamp. The trout starter soon disintegrates in the water and it is important the trays be emptied and recharged with water several times a day, with fresh trout starter sprinkled on each time. The ducklings soon come to recognize this operation and begin feeding as soon as fresh food is offered. The down of the ducklings becomes pink stained with the trout food, but this is of no concern and is not noticeable after the first moult. Once the ducklings begin to feed, they consume a surprising amount of feed. No other food, grit or green food should be offered. Attempts at feeding ducklings on sieved hard boiled eggs invariably ended in failure with the down being fouled, the ducks losing their waterproofing and dying in wet misery. Since the supply of the trout starter crumbs may be irregular, I recommend strongly, that a stock be taken in before attempting to collect eggs for incubation.

Once the ducklings have been transferred to the rearing runs outdoors, then the turkey starter crumbs can be gradually introduced to the diet so that by the time they are fully feathered at about seven to eight weeks, they are then on a diet of turkey starter only. In contrast with other waterfowl, no mention has been made of pinioning in the downy stage: I recommend the birds be left full winged and accommodated in aviaries.

Single wild- caught adults are easily reconciled to captivity and the artificial diet, if they are confined to the rearing boxes described above and subjected to a minimum of disturbance. Heating lamps are of course unnecessary. Only gruel like mixture of turkey starter and water should be added and no separated water dish should be provided to begin with. To satisfy its thirst, the duck with forced to use the thin gruel material and ingest the artificial food. Very soon it will feed readily on the turkey starter. Soon after this, the bird can be enlarged into an aviary and several feeding dishes of turkey starter distributed around.

We have had Pinkeared Ducks which have been trapped in a funnel trap and when treated as above have quickly responded and become reconciled to captivity. However, on one occasion a rocket net was used and some twenty eight birds captured. This proved to be a totally unsuitable method of capture for many of the ducks were injured in the capture and subsequent handling. The survivors, about 16, were enlarged on a small pond and although they fed continuously in the pond, they refused to try the dishes of turkey starter gruel which were distributed around the margin. The pond did not support any small animal life and most of the ducks succumbed to starvation before action was taken. The ultimate survivors were treated, one to a rearing box, until they become reconciled to the new diet and these birds did, indeed, survive.

Pinkeared ducks are rather awkward on land, although they perch freely on low branches. Accordingly, I recommend they be kept full-winged in aviaries than on opened ponds. They are unable to compete with the more aggressive waterfowl but can be kept safely with pygmy geese. However, I recommend that wild- caught adults or fully grown juveniles be wing clipped when they are first introduced into their aviary: compared with other waterfowl, they have an exceedingly fragile skeleton and if they dash against the mesh, they will suffer injury. Likewise, they must be carefully handled for there appears to be a weakness in the lumbo-sacral region and posterior paralysis is a common sequel of careless handling. The most common causes of death include septicaemia following bumble-foot which afflicts them when they are kept on an unsuitable substrate; kidney failure when the turkey starter was unauthorisedly en-riched with minced lean raw lamb’s heart; and injury to the fragile skeleton.

The small rose-pink patch of feathers which gives then their name, is poorly coloured under our conditions of captivity and I suspect that the birds may require canthaxaanthin or some similar substance to maintain this colouration. However, their attractive feather pattern, their grotesque bills and their engaging voices with their pipes and trills, make them very engaging subjects for zoo exhibition