>> More than 5 million birds are killed each year in Australia due to
>> land clearing.
>Arguably both are "bad facts", but also both are obviously pretty loose
>guesstimates. The precise number is not so important as the order of
>magnitude, which seems plausible.
I suspect that the figure is derived from RAOU Conservation Statement 10
(issued June 1996): "Conserving Woodland Birds in the Wheat and Sheep Belts
of Southern Australia" by Doug Robinson and Barry Traill. There is a
statement in it as follows:
"Throughout the woodlands region, native vegetation has been removed from an
area more than three times as large as Victoria and, up until 1995, has
continued to be lost from Queensland and New South Wales at the rate of
about 200,000 ha (or 2% of all woodland remnants) every year - that is,
about 548 hectares of woodland cleared and about 8200 birds killed every day
(Bennett 1993; Sivertsen 1993, 1994; Biodiversity Unit 1995). At these
rates, Australia ranks as the eighth-highest clearer of native vegetation in
the world (Biodiversity Unit 1995). "
The figure that comes out of this is about 3 million birds per year, and was
presumably extrapolated beyond woodland clearance to other habitats for a
guesstimate of 5 million. I agree that it is a plausible order of magnitude.
The references given are (more fully):
Bennett, A.F. (1993). Vic. Nat. 110: 15-23.
Sivertsen, D. (1993). Vic. Nat. 110: 24-29.
Sivertsen, D. (1994). Search 25: 5-8.
Biodiversity Unit (1995). Native vegetation clearance, habitat loss and
biodiversity decline. Dept of the Environment, Sports and Territories,
Birds Australia Conservation & Liaison,
Australian Bird Research Centre,
415 Riversdale Road,
Hawthorn East, VIC 3123, Australia.
Tel: (03) 9882 2622. Fax: (03) 9882 2677.
O/s: +61 3 9882 2622. Fax: +61 3 9882 2677.
Web Homepage: http://www.vicnet.net.au/~birdsaus/