Hi All,
I went to the Kakadu Beach artificially constructed wader roost on Friday
night to see what the waders do at night. I know one night does not allow a
conclusion, but you have to start somewhere.
I chose the night before full moon to ensure seamless light. I was told that
a pressure system along the east coast was likely to push the tide higher,
so I was expecting a king tide. King tides occur during the daytime in
summer, but at night during winter. I knew that the very high tide would
have covered all the roosts in the area except for the Kakadu Beach roost.
Trying to second guess the birds, I theorised one of two scenarios. Either
all of the birds would be there because their other roosts were inundated,
or else none may be there, because waders may have different habits at
night, and may use areas that they feel unsafe to use during daylight, when
predators and disturbance may be more common. I honestly didn't know what to
expect.
There were no waders at the roost. I did hear a Red-capped Plover, but
couldn't see it. I spent three-quarters of an hour there, and saw no wader
movement.
However, about three hundred terns were using the roost. I counted 281, and
then a few more flew in, so let's say 300. I counted about 19 or 20 Caspian
Terns, and the remaining 280 were Gull-billed Terns. Someone may know better
than me, but I have not seen 280 Gull-billed Terns together in SEQ before. I
contacted Trevor Ford, who frequents the area, and his maximum of Gull-bills
in the area is 112. We had 140 in Caloundra once last year.
Furthermore, I was interested in their behaviour. I have come to expect a
certain behaviour from roosting terns - fairly tolerant of each other, just
standing reasonably peacefully together. Little Terns can be somewhat
aggressive, but not so Gull-bills. On Friday night the Gull-bills seemed
ill-at-ease. There were numerous displays of aggression between individuals,
in the form of one running and attempting to drive another individual away
(no actual fisticuffs). Also, many of the Gull-bills stood swivelling their
bodies from side to side as if continually checking for danger, but not from
above. It appeared that they were on guard against each other. I am really
at a loss to explain it.
Meanwhile, my husband, a birder but not a tern afficionado, took to walking
along the waterfront to pass time, and came back muttering that most people
marry women who do normal things. What a wonderful, patient man.
cheers,
Jill
--
Jill Dening
Sunshine Coast, Qld
26º 51' 152º 56'
Ph (07) 5494 0994
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