DistributionRead full entry
Range DescriptionBotaurus 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 individuals (R. Loyn in litt. 2008) and is probably between 247 and 796 (Birds Australia in litt. 2011). Birds Australia (now BirdLife Australia) estimated the number of adult birds in 2009-2010 to be 3-16 in Queensland, 82-162 in New South Wales, 86-248 in Victoria, 12-100 in Tasmania, 26–116 in South Australia and 38-154 in West Australia (Birds Australia in litt. 2011). 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 2003-2008 (J. O'Connor in litt. 2008). 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 1980 (Marchant and Higgins 1990), 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 habitat (Pickering and Gole 2008). There are now only occasional records from Queensland (Garnett and Crowley 2000) 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 owing to changes in regional drainage, has probably had a large impact in the last 10-20 years (R. Jaenesch in litt. 2003). It is now known from just one site, Hirds Swamp, in Victoria (G. Dutson in litt. 2008). In Tasmania, the species is now recorded from only a 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 and 725 individuals in 1980 (Heather and Robertson 1997); numbers may be greater, given the lack of targeted survey work, and the large size of suitable swamps (G. H. Sherley in litt. 1999). 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 individuals (N Barré in litt. 1999, Ekstrom et al. 2000).