While thinking about the flock of needletails I watched circling over
Mt Gravatt yesterday, I came to consider the question of what the
appropriate collective noun would be for a flock of swifts circling
around for a feed. The way they circulated reminded me a bit of a
whirly whirly or dust devil. Typically, a flock of swifts is like a
small intense low pressure cell that moves in fits and starts. It is
interesting the way the cell hangs over a place for a few minutes than
suddenly shifts to another spot, and so on.
Working my way through the copious pictures I took of the cell, I was
struck by the variation in the needletails wing and tail shape. As
the birds were not moving at high speed, many didn't have the long,
pointed, swept-back wing shape and pointed tails that I normally
associate with needletails. Rather, many had shorter, broader, more
rounded wings, and a number had their tails spread. In some cases,
the spread tail had the profile of a cauliflower. In that respect,
needletails have a fair bit in common with F1-11s and other swing-wing
aircraft.
Another thing I noticed was the body shape when viewed side on -
needletails have a fair bit in common with an ideal skipping stone -
the type that would bounce a dozen times across the water if you threw
it correctly. In effect, the side profile was almost symmetrical
along the longitudinal axis - a bit like the proverbial flying saucer.
Clearly the Needletailed Swift is a bird that feels the "need for
speed".
Regards, Laurie.
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