There was a lot of clucking outside the window just after dawn. Two magnificent cock pheasants were head-to-head in dispute. Occasionally this erupted into a brief but fierce skirmish and they flew at each other, meeting chest to chest with claws raking and feathers flying. This was the only time I have seen two pheasants in the garden. One is a resident and he is seen every day stalking across the lawn unchallenged, the next best thing to having our own peacock. A pheasant's territory covers a large area which is maintained by patrolling. Hence the appearance of our pheasant in a dignified procession of one, as P.G.Wodehouse put it. To reinforce the message, he gives vent to a loud, two-syllable crow, followed almost invariably by a burst of whirring wingbeats. The pheasant's crow is audible to human ears over a mile so the much quieter wingbeating appears to be superfluous as a signal to rivals or prospective mates. But it may be that the wingbeats are creating infrasound – a noise that is too low-pitched for our ears to register. This is known to be true for the American ruffed grouse. The value of infrasound to a bird is that it carries farther than the higher-pitched sounds that we can hear. That it is audible to pheasants is suggested by their reaction to far-off sounds. On January 24, 1915, the ornithologist T.A. Coward recorded an unseasonable amount of crowing and wing-whirring. After receiving similar reports from around the country and reading the newspapers, he realised that the pheasants must have been hearing distant ships' guns at the Battle of Dogger Bank which were inaudible to human ears.
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