Curlews - Some Science

Although the species is still relatively common in the north and on islands, the population occurs at a fraction of its former density in southern mainland Australia (Near Threatened). Because most of the population occurs in Australia, global status is also Near Threatened.

Australian Population	Estimate	Reliability
Extent of occurrence	6,000 000 sq km	high
trend	decreasing	medium
Area of occupancy	100,000 sq km	low
trend	decreasing	medium
No. of breeding birds	150,000	low
trend	decreasing	low
No. of sub-populations	1	low
Generation time	5 years	low
Global population share	99%	high
Level of genetic exchange	low	high

(Source: Garnett, S. T. and Crowley, G. M. The Action Plan for Australian Birds 2000 Environment Australia)

Infraspecific Taxa

None described.

Past Range And Abundance

Recorded from all but the most arid parts of mainland Australia, as well as on many offshore islands, although not in Bass Strait and only accidental in Tasmania (Blaker et al, 1984 Marchant and Higgins 1993). A breeding population also occurs in southern New Guinea (Marchant and Higgins, 1993).

Present Range And Abundance

Almost absent south and east of Great Dividing Range between Port Fairy, Victoria and Brisbane (Blakers et al., 1984). Scarce elsewhere in southern Australia. Numbers in northern Victoria apparently decreasing, with counts of 328 birds in 1985 and 141 birds in 1991 (Johnson and Baker-Gabb, 1994, Webster and Baker-Gabb, 1993). Recent records from South Australia mostly from islands (Blakers et al., 1984). Decreasing in south-western Australia from 1920s (Johnson and Storr, 1998). In northern Australia and on many continental islands, species remains common, even within towns (Garnett, 1992). However, decreased near Rockhampton (Wilson, 1993) and in south-east Queensland (R Johnson), largely absent south and east of the Great Divide R. (A. Applemann). Genetic status of island birds is unknown; possibly isolated sub-populations as no evidence of movement across major water. Current Australian population estimated at 15,000 individuals (Watkins, 1993).

Ecology

Bush Stone curlews require sparsely grassed, lightly timbered open forest or woodland. In southern Australia, they persist most often where there is often with a well-structured litter layer and fallen timber debris (Blakers et al., 1984, Marchant and Higgins, 1993, Johnson and Baker-Gabb, 1994), but in parts of northern Australia, seem able to persist where the ground cover is more open (A. Applemann). They are thought to be sedentary, but abundance in central Australia appears to vary with rainfall (K. Johnson). They lay one or two eggs on the ground in open areas, usually well away from trees (Johnson and Baker-Gabb, 1994), and feed on a range of invertebrates and small vertebrates, as well as seeds and shoots (Marchant and Higgins, 1993).

Threats

The rarity and continuing decline of Bush Stone curlews in the southern part of the species range has been attributed to predation by introduced foxes, habitat clearance for agriculture, habitat degradation by pastoralism, and removal of leaf litter and fallen timber debris from habitat remnants (Johnson and Baker-Gabb, 1994). At one site in Western Australia the species re-appeared five years after intensive fox baiting was undertaken (S. McNee). The species was formerly hunted legally and continues to be so illegally (Marchant and Higgins, 1993, G. Graham).

Recommended Actions

1. Develop effective techniques for monitoring abundance.
2. Determine the minimum area of woodland needed to maintain sub-populations and incorporate where necessary into land-clearing guidelines.
3. Develop agreements with landholders to maintain litter layer and fallen timber debris within wooded remnants.
4. Improve fox control around remnant sub-populations.
5. Compare abundance in areas with and without rabbit baiting and, if appropriate, promote baits that are unattractive to stone curlews.

Bibliography

Blakers, M., Davies, S.J.J.F. and Reilly, P. .N. 1984. The Atlas of Australian Birds. RAOU and Melbourne University Press, Melbourne.

Garnett, S. T. (ed.) 1992. Threatened and Extinct Birds of Australia. RAOU Report 82. RAOU, Melbourne and ANPWS, Canberra.

Johnson, G. and Baker-Gabb, D. J. 1994, Bush Thick-knee in Northern Victoria (Part 1): Conservation and Management. Arthur Rylah Inst. Environ. Res. Tech. Report 129(A).

Johnstone, R. E. and Storr, G. M. 1998 Handbook of Western Australian Birds, Vol 1. Non-passerines (Emu to Dollarbird). W. A. Museum, Perth

Marchant, S. and Higgins, P. J. (eds) 1993. Handbook of Australian, New Zealand and Antarctic Birds. Vol 2. Raptors to Lapwings. Oxford University Press, Melbourne.

Watkins, D. 1993. A National Plan for shorebird conservation in Australia. RAOU Report 90:1-162.

Webster, R. and Baker-Gabb, D. J. 1993 Bush Thick-knee in Northern Victoria (Part1): population monitoring between 1985 and 1991. Arthur Rylah Inst. Environ. Res. Tech. Report 129(B).

Wilson, G. 1993. Notes on the Bush Thick-knee on the Capricornia Campus,. Stilt 15:27 - 28

Comments received from: Alex Applemann, Allan Burbidge, Allan Burbidge, Susan Davis, Gordon Graham, Richard Johnson, Richard Loyn, Shapelle McNee.

Published by WPSQ Bayside Branch