Dear Birders
The following information continues on from notes posted previously
dated 07,10,15,23 and 28/07/2000, regarding the Banded Stilt breeding
event at Ibis Island, Lake Eyre.
On Monday, 17 July the first Banded Stilt chicks were observed near the
north eastern corner of the colony. Silver Gull numbers had increased
to more than 150 and were vigorously attacking the stilts so limited
baiting was resumed and almost immediately, the attacks ceased.
Throughout the week, stilt chicks were seen emerging in ever larger
numbers and a wave of synchronous hatching was observed spreading south
within the colony. This event was now proceeding without much
harassment from Silver Gulls.
At about 10.50 hrs on Wednesday 19 July, the first two groups of Stilt
chicks emerged from samphire shrubs at the west side of the colony.
Appearing as highly mobile white fluff balls accompanied by several
chattering adults, they moved in short rapid, almost dotterel like
bursts of motion, across the 100 metres of muddy shoreline to the
surface of the lake and commenced feeding with the adults, while moving
slowly west across the shallow water. By about 11.00 hrs on Thursday,
the rate of departure from the colony increased to nearly 400 chicks per
hour and continued to increase during the warmer period of the day. By
Friday, more than 60% of the remaining nests in the colony contained
chicks and most scrapes at the southern end of the colony contained eggs
chipping out.
By Saturday morning 22 July, masses of chicks were departing in compact
groups of more than 60 each, and aerial observation indicated they were
spreading out across the lake to the south and west moving about 3.5 km
per day, with some groups up to 9.1 km from the colony. Although
accurate counting was difficult about 3 chicks per clutch and totalling
an estimated 50,000 young Stilts were produced from the Ibis Island
colony.
It was feared that the Stilt chicks were dispersing directly towards the
largest Silver Gull concentrations at Dalhunty and Hughes Islands. Lake
Eyre is now drying back quickly but the young birds are fledging rapidly
as they retreat to the deeper water near Dalhunty Island and Jackboot
Bay. Regular aerial monitoring by SANPW has not indicated any major
gull attacks on Banded Stilt chicks after entering the water and
therefore this breeding attempt should be considered a great success.
A fourth Banded Stilt breeding attempt commenced at Ibis Island in late
July however the birds deserted the colony after a few days, probably
due to the rapidly drying lake and the island margin which had receded 8
km in just two weeks joining the island to the mainland.
The South Australian Government should be congratulated for their rapid
deployment of the SANPW and their immediate action to protect the
nesting Banded Stilts. The success of this event is in no small part,
due to the efforts of concerned observers who expressed to the
Authorities, the urgent need to take action, and thus provided a
constructive environment for them to make the required decisions.
This successful breeding event has gained some time for the Banded Stilt
but close monitoring and further management intervention will be
required to ensure their future. Predation at nesting sites from an
increasing population of Silver Gulls is a real threat to the future of
the Banded Stilt and this event has exposed an urgent need to develop
and implement a national Silver Gull management program.
Congratulations and regards;
Ian May
PO. Box 666
Enfield Plaza
South Australia
Home (08 81825858)
Mob. (0409474575)
Birding-Aus is on the Web at
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