Australian brush-turkey population, Nandewar and Brigalow Belt South bioregions - endangered population listing
The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the population of the Australian Brush-turkey Alectura lathami Gray, 1831 in the Nandewar and Brigalow Belt South Bioregions as an ENDANGERED POPULATION in Part 2 of Schedule 1 of the Act. Listing of endangered populations is provided for by Part 2 of the Act.
NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. The Australian Brush-turkey is not currently listed as an endangered species in Part 1 of Schedule 1 and as a consequence populations of this species are eligible to be listed as endangered populations.
2. The Australian Brush-turkey, Alectura lathami Gray 1831, is a large ground-dwelling bird of length 85 cm, wingspan 60-70 cm and approximate weight 2.3 kg (Marchant and Higgins 1993). The species is mostly black with a bright red head and neck which is almost entirely bare in male birds but the head and neck of females are covered with small dark bristles. A yellow pouch occurs at the base of the neck in both sexes, and in breeding males this pouch becomes enlarged. The tail is prominent and laterally flattened, and the legs are strong and powerful.
3. The Australian Brush-turkey has a largely coastal distribution from Cape York south as far as the Illawarra in NSW (Marchant and Higgins 1993, Barrett et al. 2003). It occurs in forested and wooded areas of tropical and warm-temperate districts, particularly above 300 m to at least 1200 m altitude. The species is commonly associated with closed forest, including rainforest and vine thickets, as well as dense woodland habitats. More open dry woodland habitats are also used including open woodland dominated by Spotted Gum, Corymbia maculata, Brigalow, Acacia harpophylla, and Belah, Casuarina cristata (Marchant and Higgins 1993). In NSW the inland vegetation type preferred by the Australian Brush-turkey is a dry rainforest community that is found within the Semi-evergreen Vine Thicket in the Brigalow Belt South and Nandewar Bioregions Endangered Ecological Community.
4. In recent years the Australian Brush-turkey has colonised urban areas along the east coast of NSW and south-east Queensland (Jones and Everding 1991; G&uoml;th, Nicol, Ross, Shields, unpublished data). During this time, active hunting by humans ceased in these areas and the birds quickly lost a prey-reaction to human presence. The abundant food and nesting resources in forested suburbs have proved to be suitable habitat for the species, where they are now common and often troublesome residents (G&uoml;th, Nicol, Ross, Shields, unpublished data). However, recruitment within these urban populations may be insufficient to make them self-sustaining and they may be reliant on colonisation by non-urban birds (Jones and Everding 1991).
5. Male Australian Brush-turkeys build and defend large incubation mounds constructed by scraping plant material and soil from around the mound site (Marchant and Higgins 1993). Mound sites are commonly in areas of dense vegetation, both to provide ample litter for building, and for shade to reduce moisture loss from the mound. Egg incubation is entirely dependent on the heat generated from the decomposition of plant material within the mound.
6. A population of the Australian Brush-turkey is known from the Nandewar and Brigalow Belt South Bioregions. Recent records for the species show the population to range from north east of Warialda, to Narrabri, approximately 115 km to the south-west, and occur within the local government areas of Yallaroi, Bingara, Narrabri, Barraba and Moree Plains. The majority of records are from Mount Kaputar National Park and nearby Deriah State Forest, with a smaller cluster of records from Warialda State Forest. An outlying 2003 record is also known from just north of Severn State Forest, approximately 75 km north-east of Warialda, in the Inverell Local Government Area. It is thought that a western expansion in the range of the Australian Brush-turkey followed the spread in the early 1900s of the exotic weed Prickly Pear, which the species used for food and mound construction (Marchant and Higgins 1993). Currently, records nearest this population are north of the Queensland-NSW border, approximately 40 km to the north-east. There are no records between the population and the eastern escarpment, a distance of at least 120 km. The population of the Australian Brush-turkey in the Nandewar and Brigalow Belt South Bioregions is therefore both disjunct and at the western limit of the species' range in NSW.
7. The population of the Australian Brush-turkey in the Nandewar and Brigalow Belt South Bioregions is vulnerable to habitat loss and modification. Large areas of both bioregions have been cleared for agriculture and remnant vegetation is considerably fragmented. Grazing by introduced herbivores within forest and woodland areas reduces the density of vegetation and the availability of leaf litter for mound construction. Similarly, alterations to natural fire regimes, by the increased frequency and decreased patchiness of fires, decreases the availability of leaf litter and promotes the growth of fire-tolerant plant species.
8. As a conspicuous ground-dwelling animal, Australian Brush-turkeys are vulnerable to predation from introduced predators. The Feral Cat, Felis catus, and European Red Fox, Vulpes vulpes, are the main predators of chicks, while wild dogs, Canis lupus familiaris, occasionally prey on adult birds (Marchant and Higgins 1993). Feral Pigs, Sus scrofa, are also known to disturb incubation mounds. Further, habitat loss and modification reduces the availability of shelter, and increases the abundance and facilitates the movement of generalist, open-habitat predators such as foxes (Bider 1968; Angelstam 1986).
9. As a result of its limited extent, habitat specialisation and isolation, the population of the Australian Brush-turkey in the Nandewar and Brigalow Belt South Bioregions is vulnerable to extinction from stochastic events. Although a portion of the population is known to occur within a formal reserve, this may not ensure the population's continued survival in the long-term.
10. In view of the above the Scientific Committee is of the opinion that the population of Australian Brush-turkey, Alectura lathami, in the Nandewar and Brigalow Belt South Bioregions is facing a high risk of becoming extinct in nature in New South Wales and it is of conservation value at the State or regional level for the following reason: it is disjunct or near the limit of its geographic range.
Dr Lesley Hughes
Chairperson
Scientific Committee
Proposed Gazettal date: 21/10/05
Exhibition period 21/10/05 - 16/12/05
References
Angelstam P (1986) Predation in ground-dwelling birds' nests in relation to predator densities and habitat edge. Oikos 47, 365-373.
Barrett GW, Silcocks AF, Barry S, Cunningham RB, Poulter R (2003). 'The New Atlas of Australian Birds'. (Royal Australasian Ornithologists Union, Hawthorn East).
Bider JR (1968) Animal activity in uncontrolled terrestrial communities as determined by a sand transect technique. Ecological Monographs 38, 269-308.
Jones DN, Everding SE (1991) Australian Brush-turkeys in a suburban environment: implications for conflict and conservation. Wildlife Research 18, 285-297.
Marchant S, Higgins PJ (1993) (Eds) 'Handbook of Australian, New Zealand and Antarctic Birds: Volume two, raptors to lapwings.' (Oxford University Press, Melbourne).