Dear Birders
Silver Gulls in the immediate vicinity of the Banded Stilt nesting
colony at Ibis Island, Lake Eyre have been removed, and the good news is
that so far, they have not returned in any significant numbers and are
no longer causing an immediate threat to the Stilts.
The Banded Stilts are likely to commence hatching out in the next
week. The colony estimated to be at least 7 days established was
located on the 4th of July. Banded Stilts have a 22 day incubation
period and so it appears that at least 18 days have passed since egg
laying commenced. It is possible that hatching may correlate with the
approaching full moon.
Currently there are also about 20,000 nesting pairs of Silver Gulls at
Lake Eyre. The assumption being made by the National Parks and Wildlife
(NPW), the South Australian State Govt. wildlife management agency, is
that these Silver Gulls are unlikely to fly the distance across the open
shallow lake to the Banded Stilt colony from their five existing
colonies, (16.3 km to the existing closest gull colony to as far as 33.5
km to the most distant). There are some birders including myself that
are not too confident about this assumption and believe that the gulls
have the potential to cover these distances particularly when motivated
by the need to find increased food sources for their colonies when gull
hatching occurs. And to limit this threat a more direct response would
be to target these five existing large concentrations of gulls at least
until the Stilts fledge.
It must be said however that the NPW are doing a good job with limited
resources and should be applauded for their rapid response so far.
Their current plan is for the Gull Control Team to return to Ibis Island
next Monday or Tuesday and remove any gulls in the immediate vicinity of
the nesting Stilts. And then, determined by the observed feeding
behaviour of the more distant Silver Gulls when the Stilts hatch,
further strategic targeting of gulls may be undertaken.
This is a minimum response but should ensure that the Stilts hatch
successfully without further harassment from gulls. The critical
period for the Stilts will now occur after hatching. This is when the
chicks normally enter the water and swim away in small groups (crèches)
usually shepherded by only a few adults. It is at this stage that the
young stilts are particularly vulnerable to predator attacks. The NPW
intends to monitor the movement of these crèches and if the Stilts are
attacked, a response targeting the gulls will be initiated.
Thank you to all those who directed their concerns about the Banded
Stilt threat to the Premier, the Minister of Environment and Heritage
and to the relevant Government authorities. So far so good. It appears
that this response has provided a constructive environment for the
authorities to make the difficult decisions required so far. Please
consider a further response if an uninformed public debate erupts over
this necessary action to control gulls at Lake Eyre however to this
point in time there has been little if any criticism levelled and it
appears that the general public has a high level of understanding about
this serious problem.
A further update will be posted when more information is received
Regards
Ian May
PO Box 666
Enfield Plaza, South Australia, 5085
Phone/fax (08) 81825858
Mobile 0409 474575
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