Hi All,
We have had such a fascinating time in Caloundra this week, and I feel
compelled to share it with you all. I told you last week that we had more
than 42,000 terns on our 7/2/02 survey.
This week we have been out for our regular survey, but also did a second
outing last night. The objective of last night was to try to verify the
proportions of individual species in the flocks that we count against the
sky as silhouettes in the fading light.
Thursday's 14/2/02 regular survey was one of the strangest we have ever
done. During the afternoon we dealt with a mixed flock of about 12,000
terns, which bit by bit flew out to sea. This is not remarkable, as there
seems to be a consistent summer pattern of resting and then afternoon
feeding at sea. What was remarkable was that from 5.50pm, when the sandbanks
are usually starting to groan under the weight of thousands of terns, there
was not a migrant tern on the sandbanks. (The three resident species were
there.) We sat there, twiddling our thumbs, theorising, wondering. The odd
flock came in from the sea, wheeled and performed aerial acrobatics, and
flew out again to the ocean. By 6.15pm even the sky was empty. This changed
abruptly at 6.56pm when birds started to arrive low over the entrance to the
Passage. Our count was halted by poor light at 7.15pm, by which stage we had
regained about 8000 terns.
The weather was fine, the moon was new, we hear there is an abundant
baitfish season....................
And so last night (which was the following evening) I took the opportunity
to go out at 5.30pm with a generous boat person. Barb Dickson was to have
come with us, but the excitement of a due grandchild took her mind off the
game and she clear forgot. This was a blessing, because, unknown to me, she
realised her error and took herself down to our regular survey spot and did
a count of the terns flying in, whilst we were out on the sandbanks. The
evening seemed at first like a rerun of the previous evening - no terns. In
fact I felt like a fraud dragging poor Dennis Evans out in his boat.
At around 6.55pm everything changed and terns came in with the last light of
the day, flying low. They landed all around us in their thousands, with the
peak at about 7.10pm, when light faded. However, being out on the sandbanks,
we were able to see more, with the lights of Caloundra to illuminate the
arriving flocks. We finished at 7.45pm, with the odd small flock still
arriving. We had no idea how many birds were around us, but it was, well, I
am struggling to find the right words - mind blowing. I said to Dennis that
our figure of 42,000 for last week was quite credible in view of what was
around us then.
Later I learned that Barb had been out counting, and that light had stopped
her at 7.10pm with 23,000+ terns. We knew for a fact that easily as many
came in after that time as she had counted to that point.
The result?
1.
We were unable to separate the species in good light, but what I saw until
light faded gave me confidence that the species coming in at dusk are no
different from those we see during the day. I still can't say what happens
after dark.
2.
I can't really put a number on the total of birds last night. However, it
does show that a hell of a lot of birds may come in regularly after light
stops our regular surveys.
Cheers
Jill
--
Jill Dening
Sunshine Coast, Qld
26º 51' 152º 56'
Ph (07) 5494 0994
--
Jill Dening
Sunshine Coast, Qld
26º 51' 152º 56'
Ph (07) 5494 0994
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