The Pacific Black Duck Anas superciliosa is one of the most commonly seen ducks in Australian parks. There are many black ducks in the world, hence the Pacific in this bird’s name. However, it is hardly black, unless you look at them against the setting sun, in which case even white cockatoos look black. It is also called the Brown Duck (but the hardhead is more evenly brown), the Grey Duck (not that really either) or the Wild Duck (among a dozen or so other species of wild duck). This should be a lesson for you all. Firstly, common names are available and usable to most people, who often intensely dislike the mumbo-jumbo of scientific names. In any case, how many people can understand any Latin or Greek these days? Secondly, common names (and even scientific names) are often a pretty unreliable means of identification.
Black ducks can be most readily identified by their distinctive yellow and black striped faces. They have a greenish grey beak, smart dark brown body feathers with pale brown edges, and a purple-green “window” (called a speculum) in the hind wing that is readily seen when the duck is flying, and sometimes when it is walking. Black ducks are monomorphic: the males and females look pretty much the same.
Black ducks eat a wide range of foods including water insects and water plants and seeds, which they obtain by filtering water through their beaks, though they will also graze in moist grassland. As a result they have an ideal habitat — permanent waterways with dense vegetation nearby — that they will leave any less satisfactory waterhole to seek. In the Goulburn Wetlands black ducks were very common in the wet years between 2011 and mid 2012. There they were surrounded by masses of water ribbons, floating ferns and water peppers (knotweed), together with shores entangled in long weedy grasses. As weeds were removed and burned off and as the wetlands dried out, the black duck population declined until they were virtually absent, though there is usually at least one pair nearby.
Black ducks are often very confident, almost tame, in large established public parks. They will readily take food offered by people but are usually savvy enough to avoid dogs and small children. In the wild, however, it is a very different situation. Black ducks too often fall victim to illegal hunters and have, through necessity, become very wary indeed. It is not uncommon for canoeists, for example, to first become aware of black ducks when they fly loudly quacking away from them. And this brings up another point. Black ducks are very closely related to domestic ducks, or rather, their wild ancestor the Mallard. This is one of the few duck species that actually does quack, and so do black ducks. The bad news is that mallards and black ducks readily interbreed, and female mallards look very similar to a rather pale version of the black duck. This hybridisation may have long term impacts on the integrity of black ducks as a species. In places where both species are present there can be extensive hybridisation. For this reason it is strongly advisable not to let people dispose of their unwanted domestic ducks in the nearest river or pond.
Black ducks nest in secluded places, usually amongst dense vegetation beside permanent water holes, often on the ground. Breeding took place in the wetlands in 2011 when weeds, high water levels and a diversity of water plants was available. Since then, with clearing of weeds (they are being replaced with native plants of similar structures) and lowering water levels, no breeding has occurred of this species in the wetlands. Hopefully that will change in the not-too-distant future. They produce many young and, in ideal conditions, can reproduce rapidly and repeatedly. Unfortunately they have a high mortality rate. Ducklings have to survive predation from eels, musk ducks, large fish (when and if they occur), water rats, black rats, cats, foxes and dogs, not to mention the occasional sadistic human. Adult ducks suffer such high mortality rates from shooters that in some places where shooting has been permitted (such as Victoria), black duck numbers are in decline. Another very serious by-product of shooting for human entertainment is the increasing risk of lead poisoning. Popular shooting places often have sediments that are all too rick in lead pellets from shotguns and other weapons of mass destruction. These are often dredged up by waterfowl such as ducks and swans. The pellets are used as gravel would be. Since birds have no teeth they swallow grit or gravel which grinds the food up in their churning gizzards. As a result lead poisoning is becoming an increasing problem,and it is unrealistic to expect shooters to retrieve every pellet. There has, moreover, been a move in recent years to replace lead with dense plastic that could resolve at least one of the problems facing the black duck.