During the afternoon of Tuesday 04 July 2000, a colony of more than
10,000 pairs of Banded Stilts were located on Ibis Island at Lake Eyre
North, South Australia. This is the third Banded Stilt breeding event
recorded at Lake Eyre since the floods of February and March earlier
this year when Dr. Clive Minton first located them there.
The current colony may well represent the entire remaining adult
breeding population of this species and if not, is probably the whole of
the eastern population. There were also two separate colonies of
Caspian Terns totaling about 450 pairs on two nearby islands
Of major concern is that also in the vicinity of the Banded Stilt
nesting site are six separate colonies of Silver Gulls each comprising
from about 1,500 to 5,000 pairs and totaling at least 16,000 and
possibly more than 20,000 pairs (More than 40,000 Silver Gulls at Lake
Eyre), with the potential to produce more 100,000 young from repetitive
nesting events.
The Banded Stilt is a unique species, endemic to Australia. Up until
now, they have been considered to be relatively abundant. Frequently
observed in large flocks at salt lakes and salt works in temperate
southern and western coastal areas, the breeding behavior of these birds
is considered somewhat mysterious in that it has seldom been seen by non
aboriginal people. The reason for this is because Banded Stilts breed
at remote, normally dry inland desert salt lakes and then only after a
very occasional flood (perhaps less than once each decade). The flood
must be sufficient to stimulate their food source and provide suitable
island habitat. The Banded Stilt is completely defenseless against
predators, its only developed protection strategy appears to be mass
breeding events and nesting colony isolation.
This years two previous nesting attempts at Lake Eyre have been
completely decimated by Silver Gulls and it appears that from the total
of more than 25,000 Banded Stilt nests recorded in these two previous
breeding events so far, not a single juvenile has successfully fledged.
Silver Gulls prey on Banded Stilts in at least two different ways.
While the Stilts are sitting on eggs, the gulls form loose flocks of up
to thirty birds or more and swoop continually, knocking them from their
nests and then others gulls charge in and take the eggs. When
incubation is complete, hatching occurs mostly over a 48 hour period .
The chicks take to the water almost immediately and raft into groups of
sometimes hundreds forming crèches and soon after swim away from the
island, shepherded by just a few adults. This is probably a disease
avoidance strategy but at this time the chicks are completely vulnerable
and are picked off by large marauding flocks of Silver Gulls.
It needs to be understood that current levels of Silver Gull impact on
Banded Stilts cannot be considered a simple event of nature, or just
nature taking its course, because the population of Silver Gulls have
exploded in the last two decades due to the proliferation of garbage
dumps, aquiculture sites and other man made developments that provide
the ideal habitat to support their breeding and as a result, gull
numbers have exploded and are causing an extreme unbalance in the prey
predator relationship. Also of great concern is a possibility that
Silver Gulls raised from the results of preying upon Banded Stilts may
be imprinted by this behavior and because the current Silver Gull
colonies at Lake Eyre are likely to produce more than 100,000 birds if
left unchecked, the effects of this would be serious and hard to
estimate.
During the 1930's Banded Stilts were located at Lake Callabonna by
McGilp and Silver Gulls were not prominent in his report. From his
series of published photographs, almost no gulls can be seen. During
1971 and again in 1974, the author of this note studied Banded Stilts
after flooding at Lake Callabonna. There were more than 100,000 Banded
Stilts seen but the gulls were counted at less than 200 birds. At Lake
Eyre in 1984, two day old Banded Stilt chicks were found, and although
Silver Gulls were not counted at this time, it appeared their numbers
were insignificant compared to the population of Stilts. In 1989,
Banded Stilts bred twice on Lake Torrens, and although the first event
was preyed upon by Silver Gulls, tens of thousands of stilt chicks were
seen to fledge. However only a few weeks later, the second breeding
event was all but destroyed by Silver Gulls, the numbers of which had
increased to several thousand over the short period since the first
successful event.
Now that Banded Stilts are making a third attempt to nest on Lake Eyre
this year, it is imperative that those concerned about the future of
the Banded Stilt consider supporting an urgent Silver Gull control
program. There is no time to procrastinate on this issue and time is of
the essence because the colony is already established and may only be
days away from hatching. It is completely predictable that the Silver
Gulls gulls will attack and decimate the Stilts unless a major campaign
of control is immediately undertaken at Lake Eyre.
During the last recent Banded Stilt breeding event, The National Parks
and Wildlife (NPW) which is a section of the South Australian Department
of Environment and Heritage, attempted a trial control program targeting
the gulls, however when the work crew arrived ,the Stilts had already
been decimated by the gulls and so because of perceived concern about
political backlash from those people who oppose the culling of the
gulls, the project was canceled subject to any future Banded Stilt
breeding attempt.
Within 24 hours of locating this latest Banded Stilt colony, NPW has
deployed a control team of highly trained and skilled workers, however
they have been sent out again with a restricted term of reference; only
to control gulls in the immediate vicinity adjacent to the Stilt
colony. While they must be congratulated for their rapid deployment,
their action will almost certainly be an insufficient response resulting
in little overall impact on the vast population of Silver Gulls at Lake
Eyre with all the consequences associated with that.
The minimum response urgently needed must include targeting Silver Gulls
at the the six known concentrations at Lake Eyre using alpha-chloralose
baiting techniques. The method of baiting should include aerial
baiting to cover the vast areas involved and to maximize the limited
resources available. This baiting should be targeted at specific
isolated gull colonies and concentrations only over land and be followed
up by hand dispersion of baits on the ground where necessary.
This method using alpha-chloralose in bread baits to control gull
eruptions is a proven technique and its effects are as humane as
possible. Using bread baits avoids any non target effects. The use of
alpha-chloralose for gull control has recently been discussed on this
site by others (Ref. John Nankervis; Richard Johnson;, Mon.12 June) and
no further attempt is made here to explain it. During the period of
Stilt colony occupation there should also be a strategically placed
marksman stationed in a hide near the Stilt colony, equipped with a .22
cal. silenced rifle for the purpose of destroying gulls that are
attacking the stilt colony. This tactic should only be deployed as a
last resort and its effects closely monitored. Fortunately Banded
Stilts are not easily disturbed from their nests and in some cases will
sit to a point of allowing human contact before moving, so silenced
shooting is practical and unlikely to disturb them. In any case the
gulls would likely become very wary and keep their distance. Gull
carcasses should be collected where possible and placed into pits and
incinerated before covering, to avoid spread of disease
It is realized that the content of this note to the group is
unpalatable, however to do nothing will almost certainly be to witness
the demise of the Banded Stilt. They rely on mass numbers to survive
extended drought and to breed successfully. The breeding population
appears to have suffered a massive decline reduced from more than
100,000 pairs in 1989 to a current estimated breeding population of not
much more than 10,000 pairs.
There are few of us that would intentionally hurt any animal, and while
the Silver Gull control program will seem extreme to some, in this
instance there are no other viable methods known to control gulls in
this situation and if the program does not proceed immediately, we may
well see Banded Stilts diminish as a viable species. It is that
serious.
It is unlikely that we will get another chance in the near future to
anything effective towards the conservation of Banded Stilts. The
prevailing weather conditions at Lake Eyre will begin to deteriorate
soon due to hot dry winds which often occur from the middle of August
and this will probably prevent any further successful breeding attempts
after this one. It may be many years before conditions are suitable
for Banded Stilts to breed again and when that happens, what will be the
future of Banded Stilts when Silver Gulls attack them again?
It has even been suggested by some that the cause of unsuccessful
breeding attempts so far is just nature taking its course and by others
that the cause could have been human intrusion into the stilt colony,
but this clearly is not the case here. As stated above, Banded Stilts
do not readily leave their nests and it appears more likely that the
decision makers are more concerned (probably unfounded) about the
potential of a political embarrassment if there is adverse reaction to
culling the gulls.
Most of us will feel the dilemma and conflict of interest when
considering this matter. Relating to Australian wildlife management
challenges, never before have I seen an issue that is so threatening to
a species as this one, but in so saying, there has rarely been any other
issue where the action required is so easily identified and plain to
define.
Persons concerned about the future of Banded Stilts could consider
strongly supporting the NPW control of gulls at Lake Eyre and supporting
their actions if any controversy irrupts about controlling gulls. We
should also consider contacting both the Director, National Parks and
Wildlife, Adelaide and Office of Minister of Environment and Heritage,
30 Wakefield Street, Adelaide. South Australia. Tel: 08 82265855
Email and also the Premier of South Australia,
178 North Terrace, Adelaide, South Australia 5000. Tel: 08
83032290. Email: and offer our support and
advise that the current Silver Gull control project at least targets the
six known Silver Gull concentrations at Lake Eyre, preferably with
aerial baiting with the aim of culling as many Silver Gulls as possible.
If the South Australian Government implements this action we should
congratulate them for undertaking their mandate, to protect the wildlife
and the bio-diversity of this remarkable country. It does not bear
thinking about the alternative if the Banded Stilt falls into peril, and
follows the demise of the American Passenger Pigeon, a bird that in its
time could have been saved by competent government action.
Please accept my regret for the lack of editing, inconsistency and
bibliography that probably should accompany this report, but time is of
the essence for posting this report.
Thank you all and regards;
Ian May
PO. Box 666
Enfield Plaza
South Australia
Home (08 81825858)
Mob. (0409474575)
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