Tasmanian Native Hen
The Tasmanian native hen (Gallinula mortierri) is a rooster sized flightless bird which shares it's most recent ancestry with the flight-able Dusky moorhen but is unique amongst Gallinules in a number of ways. This bird stands only ½ meter tall but legend credits it with a speed in excess of 50kph. Locals call it 'The Turbo Chook' but Tasmania's native hen is not related to the domestic chicken. It belongs to a group of waterfowl: the Gallinules or rails.

Now endemic to Tasmania, the native hen once occupied large areas of southeastern Australia. Their disappearance from the Australian mainland is most likely attributable to the introduction of the fox and the dingo there. Native hens are a familiar sight throughout much of Tasmania, along river flats, in marshland and open paddocks. Farming since European settlement has in fact appreciably extended their range. Populations thin in highland areas though some do exist at altitudes of over 1000m, and they are scarce too in the densely forested southwest corner of the state.

The species live in multi-generational groups consisting of between 2 and 17 individuals. Each group is a homogeneous and well-integrated social unit. Mating systems are highly variable with monogamy, polyandry, polygyny and polygynandry existing in a single population. Offspring become sexually mature at one year old but two thirds remain in their natal territory for a further year prior to joining other groups, forming new groups or remaining permanently in their natal territory. Single solitary individuals are sometimes seen; these birds are known as floaters, they exist in a state of transition and are effectively without group membership.

The diet of the Tasmanian native hen varies seasonally. Most of the year a variety of green herbage (especially grasses) makes up the main proportion of their food. If green pickings run short during dry summers they may revert to grass seeds : chickweed, danelion, clover and thistle seeds. During the breeding season (September -March) small insects are also taken: earthworms, beetles (mainly weevils) and less frequently tadpoles, and are often fed to chicks.

In contrast to other rails Tasmanian native hens have an extensive vocal repertoire. For an open living flightless bird communication is important. 14 separate calls have been recorded. Most familiar is the low grunt alarm call and a two-syllable aggressive call that is antiphonal; containing responses sung in alternation; (apparently the late Spike Milligan's favorite sound!). This aggressive, "See-saw" call is made by the male and the female in near perfect interpolation and sounds rather like a saw cutting metal. It is thought to function as a mate-guarding signal to neighboring groups. Groups exist side by side in relative harmony, however vigorous territorial disputes erupt when trespassers cross territory boundaries. The owners drive other native hens out of their territories by an elaborate display, or fight them if they remain.

Previous researchers have noted little evidence of dominance hierarchies within groups. Current studies hope to overturn this view that heirarchies are not a feature of group life in Tasmanian native hens. A new working hypothesis is that certain individuals are more successful in defense against certain other trespassers, and when a trespass occurs the chain of command is 'transferred' to the experienced defenders who have had a history of success against those particular interlopers.

When fighting, opponents jab and grasp at each other hard with their bills especially around the head and neck. This can escalate into a series of vertical leaps, 75-150cm high, and include grappling and violent ripping with toes and carpal spurs until the victor noisily chases the loser beyond the territory boundary with a screaming cackle. During such chases defenders often flap their wings to gain extra speed and a wing may be held vertically to assist in executing tight turns.

Prepared by: Martin Pepperday
School of Zoology
University of Tasmania.