At 17:26 14/01/2002 +1100, Kym Bennet wrote:
Leg flags are in fact uncontrolled rudders with no
bearings. On a small bird such as a Red-necked Stint,
the leg flags have a combined surface area greater
than 15% of the total surface of the bird. This is
most significant. Now I don't claim to be an impartial
aeronautical engineer however one does not need to be
an intellectual giant to assume that combined with
their additional weight, attaching numerous large
uncontrolled rudders to a small flying object would
have a radical influence on it's control, particularly
in strong winds.
Where do you get 15% from? A leg flag for a Red-necked Stint is a max 1cm
long and less than 0.5cm high. Allowing for both sides this gives about 1
sq cm area. This might be 1% of the total surface area of a Red-necked
Stint. The weight of the flag and the band are about 0.2 to 0.4 grams. A
Red-necked Stint weighs 30 grams plus. Again, the weight is about 1%. The
bird shits more weight than the flag and band!
So the rest of your logic is irrelevant.
The leg flags are loose anyway, and so would face away from the wind (or
are tucked up when the bird is flying). If you have seen Red-necked Stints
in a strong wind, then they sit in low depressions or sometimes they even
squat and so they are out of the wind.
So lets get rid of this myth that leg flags affect birds in flight or roosting.
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