Hi consumers of the birding net.
David Geering asked:
Mike Tarburton: Is Dubbo the swift capital of Australia right now? Is this
likely to be the same large flock I saw a few weeks ago? How "resident" are
swifts at this time of year and are these large numbers merely a
concentration of birds near storm fronts, ie are they more spread out when
the weather is fine?
May I start with the last question and work backwards? Swifts will certainly use rising air whether at weather fronts of cliffs, or over fires, to gain an easy ride and to consume the insects being lifted up by the rising air. This means that you can get some large groups feeding on the restricted (in area) rich resource. However, you can also find large groups feeding where there are no storms fronts, the common denominator being that it will be a rich area, or they will be passing through to a rich area.
"Residency" Some swifts appear to stay in areas with reliable food supplies, but they will leave those areas to do a bit of opportunistic feeding, and I suspect that others (particularly if they have had their favourite spot cleared) will be on the move looking for a food supply.
In that there is a trend for masses of WTN to move into Victoria in Jan /Feb and then into Tassie in March (see HANZAB for more details) it is obvious that not all stay put in their favourite haunts in Qld and coastal NSW. There are exceptions to this. Beenak Firetower area gets WTN earlier than most of Vic, and they can be seen there almost every day, as is the case in other parts of Gippsland. However the other parts of Gippsland have not had many in the last year or two.
Are they the same birds? My small experience with radio tracking says they might be, but the flocks break up and merge so there is still quite a bit of fluidity. Bit they could also be a totally different group - very hard to know.
Dubbo? Well unless the Zoo attracts swifts! Actually the only records for Dubbo in my main database are those David has sent in including those from Janice Hosking and Damon Oliver. So if it is the Swift Capital then it has been undiscovered, so keep looking, (and please let me know what you find).
Happy swift watching to you all.
Mike
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Dr Mike Tarburton
Biology
Pacific Adventist University
PMB Boroko
Papua New Guinea
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