Monday, June 11, 2012
Botaurus poiciloptilus Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_offStatus_en_onStatus_cr_offStatus_ew_offStatus_ex_off Summary Classification Schemes Images & External Links Bibliography Full Account Taxonomy Assessment Information Geographic Range Population Habitat and Ecology Threats Conservation Actions View Printer Friendly Taxonomy [top] Kingdom Phylum Class Order Family ANIMALIA CHORDATA AVES CICONIIFORMES ARDEIDAE Scientific Name: Botaurus poiciloptilus Species Authority: (Wagler, 1827) Common Name/s: English – Australasian Bittern Assessment Information [top] Red List Category & Criteria: Endangered C1 ver 3.1 Year Published: 2009 Assessor/s: BirdLife International Reviewer/s: Garnett, S., Butchart, S., Bird, J. Contributor/s: Herman, K., O'Donnell, C., Blyth, J., Tzaros, C., Bell, B., Garnett, S., Holmes, T., Miskelly, C., Loyn, R., Wakefield, B., Watson, D., Burbidge, A., Jaensch, R., Barré, N., O'Connor, J., Sherley, G., Ford, H., Christidis, L. Justification: This species is listed as Endangered because it has a very small and rapidly declining population owing to loss and degradation of its wetland habitats. Urgent action is a priority to halt declines in Australia. History: 2008 – Endangered 2006 – Endangered 2004 – Endangered 2000 – Vulnerable 1996 – Endangered 1994 – Endangered Geographic Range [top] Range Description: Botaurus poiciloptilus occurs in the wetlands of southern Australia, New Zealand and New Caledonia (to France). In Australia the population is now estimated to number not more than 1,000 mature individuals15. Consecutive atlas censuses in Australia have shown a marked decrease in reporting rate; the species was recorded in 260 10-minute grid squares in 1977-1981, 142 grid squares in 1998-2003, and just 61 in 2003-200816. The declining reporting rate was particularly pronounced in the Riverina (63%), Tasmania (>90%), and south-west Australia (>90%). This decline in reporting rate is thought to represent a genuine population decline over the period. In Australia, most birds are in the Murray-Darling basin and adjacent coastal areas. In Western Australia, the population was estimated to contain up to 100 pairs in 19807, but it is now much reduced, with the largest concentration in the Albany and Lake Muir wetlands. There have been no confirmed records from the Swan Coastal Plain since 1992 and surveys conducted in 2007 and 2008 found that half the wetlands that supported the species in 1980 now retained no suitable habitat17. There are now only occasional records from Queensland5 and there appears to have been no great influx to remnant wetlands after the recent drought, as might have been expected if they were more common inland. In South Australia, breeding is confined to the south-east, however, loss of suitable habitat at Bool Lagoon, arguably the key site in Australia for this species, and other wetlands in the area due to changes in regional drainage, has probably had a large impact in last 10-20 years13. It is now known from just one site, Hirds Swamp, in Victoria18. In Tasmania the species is now recorded from only handful of sites and several of the major lakes that it once occupied have been dry for some years. In New Zealand, the estimated population was between 580-725 individuals in 19806; numbers may be greater, given the lack of targeted survey work, and the large size of suitable swamps9. In New Caledonia and Uvea, there have been just two recent records of single calling males, and the population is not thought to exceed 50 individuals1,3. Countries: Native: Australia; New Zealand Present - origin uncertain: New Caledonia Range Map: Click here to open the map viewer and explore range. Population [top] Population: In New Zealand, the estimated population was between 580-725 individuals in 1980 (Heather and Robertson, 1997). The population on New Caledonia is not thought to exceed 50 individuals. Following apparently rapid declines, the Australian population is now thought to number fewer than 1,000 mature individuals (R. Loyn in litt. 2008). Population Trend: Decreasing Habitat and Ecology [top] Habitat and Ecology: It has fairly specific habitat preferences, preferring shallow, vegetated freshwater or brackish swamps where there is a mixture of short and tall emergent sedges and rushes4. It has been recorded in paddies in the Murray Darling basin, but it is not thought to use such habitats for breeding18. It usually lays four eggs. It feeds, mostly at night, on fish, eels, frogs, freshwater crayfish and aquatic insects6. The population seems to increase rapidly in good years and decline rapidly in poor ones12. Systems: Freshwater; Marine Threats [top] Major Threat(s): In Australia and New Zealand, the main threats are wetland drainage for agriculture, as well as changes brought about by high levels of grazing and salinisation of swamps2,4,5. In Australia, the species appears able to adapt to the availability of ephemeral wetlands, but is likely to be particularly sensitive to the destruction of drought refugia. Loss of these habitats may explain its decline in Western and South Australia5. The Murray-Darling basin, a former stronghold of the species, has suffered consecutive droughts in recent years and over-extraction of water is an ongoing problem14,15. Shooting and flying into powerlines are additional contributory causes2, but hunting pressure is very low11. Conservation Actions [top] Conservation Actions: Conservation Actions Underway In Australia, Bool Lagoon and Lake Muir are managed specifically for the species5. In Australia, recent initiatives by the Threatened Bird Network to survey Painted Snipe Rostratula benghalensis australis will contribute to the information on the distribution of this species10, 18. Conservation Actions Proposed Complete field surveys to determine current global distribution, status and key sites for conservation1,5,8. Develop methods for assessing population trends5. In New Zealand, determine factors that may be limiting populations8. In New Caledonia, obtain legal protection of representative, low altitude habitats1. Protect remaining sites against drainage or salinisation. Rehabilitate former breeding sites5. Citation: BirdLife International 2009. Botaurus poiciloptilus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2.
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