(I’ll just type that out, mostly for the benefit of search engines.)
Some birds can fly into a wind with a greater velocity than their own maximum speed and still move forward, although the reasons for this are not known. Meinertzhagen once saw a small group of common eider (Somateria mollissima) perform this remarkable feat in South Uist, Outer Hebrides during a 90-95 mile/h 145-153 km/h gale. ‘This particular wind was so strong’, he writes, ‘that shooting was out of the question, wild swans were grounded and unable to rise and we experienced the greatest difficulty walking against it. Eider duck had come inland from the sea and were sitting about on the short grass. When disturbed they would rise into the wind and make headway against it at ground level, doing about 15-20 mph except one bird who actually achieved a minus ground speed and slowly backed towards us.’
There is also a record of a flock of wood pigons (Columba palumbus) moving forward at 40 miles/h 64 km/h in the face of a 110 mile/h 177 km/h gale when they should have been moving backwards! (McNabb, 1953).
Wood elsewhere gives the maximum speed of the eider duck (Somateria mollissima) as 30-35 mph 48-56 kmh, so the ducks in Meinertzhagen’s story were doing something north of three times their usual maximum air-speed.
Unfortunately, the reference corresponding with the McNabb 1953 citation is extremely uninformative: “McNabb, D (1953). Field (22 Feb).” That’s it. Anyone know what it means?
Anyway, my question is: this is complete nonsense, isn’t it? Birds fly by pushing against the air, not the ground, so surely — surely — the only speed that matters is air-speed?
Am I missing something? Is this possible? Has it been documented under laboratory conditions? Has it been observed in the wild other than by Meinertzhagen and McNabb?