From Tropical
Topics newsletter, No. 73 May 2002, produced by Stella
Martin at the Queensland Environmental Protection Agency. Download
the PDF to read the whole issue.
The tropical savannas of northern Australia are home to a large
number of seed-eating birds — 55 of Australia's 90
seed-eating species are found there. They include parrots, quails,
pigeons and a particularly large representation of finches; 14 of
Australia's 18 finch species inhabit the savannas.
However, studies have shown that many of these birds are in
trouble than any other group in the savannas and savanna
seed-eaters are in more trouble than those elsewhere in Australia.
Intensive studies of selected species have indicated some common
problems.
The early wet season is a particularly stressful time for
seed-eaters. Most grass seeds germinate with the early rain, making
it difficult for the birds to find food. Many juveniles die at this
time of year if they have not developed strategies for finding new
food sources and learned to quickly identify ripe seed.
A common theme in seed-eater decline seems to be changed fire
regimes. In the past, according to historical records indigenous
people lit fires at almost any time when it wasn't raining. Areas
burnt at any one time tended to be relatively limited, resulting in
a complex mosaic of small burnt and unburnt patches. The steady
removal of fuel meant that fires over extensive areas were fairly
rare. This pattern suited the seed-eaters well, leaving pockets of
seed at different stages of maturity to sustain them through the
year.
Fire regimes have changed with the advent of pastoralism, though
patterns vary amoung landholders. The concentration of fire during
the dry season means that areas burned are often extensive. This
limits the amount of food available to the birds. As studies of the
birds' requirements illuminate the need for patchy burning,
landholders are beginning to adopt new burning regimes. For
graziers, this also has the advantage of halting the loss of
grasslands, which are being invaded by woodland in many places. For
the birds, it could mean a future.
No fewer than 13 species, plus 10 additional subspecies, of
seedeating birds are endemic to the savannas, meaning that they
live nowhere else in the world.
Click on the species below to see a recent list
of research findings or see the links below for Tropical
Savannas CRC research projects related to the birds in bold.
Sub-species:
Articles
Fire, grazing and partridge pigeons
Partridge pigeons are one of a large number of tropical seed-eating birds whose abundance and distribution have declined this century Fiona Fraser one of the TS-CRC’s PhD students has been studying the needs and habits of the… [
read more...]
