The Australasian Bittern is threatened across its range by loss and degradation of suitable wetlands. This poorly know species is listed as Endangered at the global level (IUCN Red List), but not currently listed under the EPBC Act. The distribution of the species from the first Atlas (1977-1981) and the New Atlas August 1998 to July 2003 and August 2003 to July 2008 are shown below. The number of 10-minute grids in which the species was recorded has decreased between each five year period.
1977-1981 260 10-minute grids
Aug 1998-July 2003 142 grids
STYLE--> Aug 2003-July 2008 61 grids
Click on maps to enlarge
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STYLE--> For the past two years we have appealed for observers to submit their records of Australasian Bitterns to us. We have been surprised by how few reports have reached us and fear that the species may be rarer than has been thought. We feel that there is an urgent need to organise a Bittern survey, looking for both Australasian and Australian Little Bitterns across south-east and Western Australia this spring and summer. In Western Australia surveys are being coordinated by BAWA. We would like observers to get out and check their local wetlands for these species. Due to their skulking nature, they are difficult to detect and two different types of survey are proposed - listening surveys and wetland walks. To get involved download the ID kits at the bottom of the page and contact us for more information.
Listening Surveys
Both Bittern species call at dusk and dawn through the spring and early summer at their breeding sites. Listening surveys should be conducted around sunset or sunrise. The number and location of calling birds should be recorded. At some sites where numerous birds are detected, more intensive techniques may be required to accurately access the number of calling birds.
Wetland Transects
We suspect that many Australasian Bitterns do not breed if conditions are not suitable. Non breeding birds would appear not to call, so the best way of detecting them is by walking through or around the wetland to try to flush the birds.
We are currently going through Atlas data to identify sites where Bitterns have been recorded. If these sites have water, we would like them to be surveyed this spring/summer using the two survey methods outlined. If you have a local wetland that you are able to survey, please contact us and we will send you a survey package. We will also be contacting observers living near potential sites to ask them to assist us with this survey.
Contacts
South-east Australia - Andrew Silcocks 03 9347 0757 Western Australia -
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08 9312 1671
Downloads
Little Bittern call (mp3) recorded by Marjorie Paul near Nathalia VIC Australasian Bittern call (mp3) recorded by Andrew Corrick near Casterton VIC and Roger Jaensch at Lake Pleasant View WA