Islands are often attractive destinations for bird-watchers because of their high proportion of endemic species (species that occur nowhere else). Australia is no exception, as it has among the highest number and proportion of endemic bird species of any country. This proportion is particularly high in Tasmania. Of the 140 native bird species that breed in Tasmania, 12 are endemic, and another two migratory species breed exclusively in Tasmania. This situation contributes to Tasmania’s being one of the five most popular places for bird-watchers to visit in Australia.
One of Tasmania’s 12 endemic bird species is threatened with extinction. This is the forty-spotted pardalote Pardalotus quadragintus, which is listed as endangered in the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 and the Tasmanian Threatened Species Protection Act 1995. The distribution of this tiny bird has contracted from a wide area across eastern and northern Tasmania and the central highlands, to just a few offshore islands and adjacent coastal areas on Tasmania’s east coast. The largest populations are on Maria and Bruny Islands, with smaller numbers on Flinders Island and the Tasmanian mainland near Bruny Island.
Estimates of the forty-spotted pardalote’s population size indicate that the species’ abundance is continuing to decline. A survey done in 2009-2010 estimated the total population at 1500 ± 300 individuals, indicating that it had declined by around 60% in the preceding 17 years. This decline included apparent disappearance from two areas that it had inhabited 17 years earlier: Taroona, near Hobart; and Lime Bay on the Tasman Peninsula. Of the 102 colonies surveyed in 2009-2010, only five did not show a decline in abundance in the past 17 years. The largest colony that had not declined was at ‘Inala’, a private nature reserve in the south of Bruny Island and base for an ecotourism business specialising on bird- watching tourism. This colony comprised 68 individuals, making it the largest population on Bruny Island.
The persistence of the forty-spotted pardalote colony at ‘Inala’ can be attributed to a number of factors:
(1) The species feeds almost exclusively from one species of tree, the white gum Eucalyptus viminalis, which has been extensively cleared for agriculture. Over 50% of the grassy white gum forest in south-east Tasmania has been cleared since 1800. At ‘Inala’, however, ongoing planting of this species (in areas that were cleared for agriculture in the 1840s) is increasing the food resource available to forty-spotted pardalotes.
(2) When foraging from white gums, forty-spotted pardalotes mostly gather a sap exudate called manna from the young shoots of the trees. Many of the stands of white gum where forty-spotted pardalotes occurred have declined in health, and now have sparse canopies with few young shoots. In contrast, at ‘Inala’ the white gums have dense and actively growing canopies that clearly provide abundant manna. While feeding chicks, the birds at ‘Inala’ can be seen with manna in their bills.
(3) Inala is providing nesting habitat for forty-spotted pardalotes. The species nests in tree hollows, a resource that is scarce in the young regrowth stands of white gums planted at ‘Inala’, and there is competition for nesting sites between forty-spotted pardalotes and slightly larger striated pardalotes. To overcome this shortage of nest sites, wooden nest boxes have been installed in the white gums and these have been found to be readily used by forty-spotted pardalotes.
(4) In addition, the owner of ‘Inala’, Dr Tonia Cochran, recently purchased 400 ha of land adjoining ‘Inala’, which supports forest that includes white gums likely to be suitable habitat for forty-spotted pardalotes, as well as cleared land on which white gums grown from seed collected on ‘Inala’ will be planted.
Inala’s efforts to protect forty-spotted pardalotes date from the early 1990s when Dr Cochran first acquired the property. They depend heavily on the success of Inala’s ecotourism business, a fundamental objective of which is to generate the income required to protect the reserve. The business provides the majority of funding for conservation work at Inala. Personally tailored and scheduled bird- and wildlife-watching tours with expert guides are offered, including tours of ‘Inala’, Bruny Island, Tasmania, across Australia; and international tours to New Zealand and South Africa. Guests can also stay in two cottages on the Inala reserve, and from there, roam around ‘Inala’ on kilometres of maintained walking trails. A canopy platform for viewing forty-spotted pardalotes has been constructed among the white gums on ‘Inala’ within sight of four of their nests. In addition to forty-spotted pardalotes, another five threatened bird species (swift parrot, the Tasmanian subspecies of the wedge-tailed eagle and masked owl, white-bellied sea eagle, and the white morph of the grey goshawk) and all of Tasmania’s endemic bird species can be seen at ‘Inala’. Hides have been constructed for guests to view these and other species. The property is also a base for rehabilitation of orphaned and injured wildlife, and also has a garden which comprises 400 species of plants illustrating the biological links between continents that were once connected, forming the supercontinent Gondwana. Learn more at:
Dr Andrew Browne supplied the photographs for this article. He is a bird photographer and retired veterinary surgeon.
Dr Andrew Hingston is a tour guide at Inala Nature Tours and research ecologist who has studied the effects of forest harvesting and fire on Tasmanian birds, pollination of Tasmanian plants, and impacts of an invasive species of bumble bee.
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