Far richer picture of life by pigeons
Pigeons are known to be excellent navigators. For years, scientists have been baffled as to why they get lost when released from a particular place in New York State. New research suggests the birds cannot hear the low frequency sounds at this location and get lost.
The puzzle of the vanishing pigeons began in the 1960s. Professor Bill Keeton, Cornell University, Ithaca, was trying to study the birds’ astonishing ability to navigate their way back home from places they have never previously visited.
He released pigeons from different locations at New York State, but was surprised to discover that whenever the pigeons were released at Jersey Hill, near Ithaca, they became disorientated and flew about aimlessly. This happened repeatedly, except once on 13 August 1969 when the birds’ navigational prowess returned and they flew back.
Dr Jonathan Hagstrum, Research Geophysicist, US Geological Survey, has now come up with an explanation for this baffling phenomenon. He said, “The way birds navigate is that they use a compass and they use a map. The compass is usually the position of the sun or the earth’s magnetic field, but the map has been unknown for decades.” He adds, “I have found they are using sound as their map and this will tell them where they are relative to their home.” According to him, the pigeons use “infrasound,” an extremely low-frequency sound that humans cannot hear, reports BBC.
He elaborates, “The sound originates in the ocean. Waves in the deep ocean are interfering and they create sound in both the atmosphere and the earth. You can pick this energy up anywhere on earth, in the centre of a continent even.” He thinks that when the birds are at their unfamiliar release site, they listen for the signature of the infrasound signal from their home. They use this to find their bearings. However, infrasound can be affected by changes in the atmosphere. Dr Hagstrum used temperature and wind records taken from the dates of the various experimental releases to calculate how the sound would have travelled from the pigeons’ base to Jersey Hill on 13 August 1969.
“The temperature structure and the wind structure of the atmosphere were such in upstate New York that the sound was bent up and over Jersey Hill,” he explained. This meant the birds could not hear it and so got lost -- apart from one exceptional day. “On 13 August 1969, there was either a wind shear or temperature inversion in the troposphere that bent the sound back down so it arrived right back at Jersey Hill, New York, on that day, and that day alone,” he noted.
Tim Guilford, professor of animal behaviour from the University of Oxford, claims: “Access to atmospheric odours is usually necessary, and often sufficient, to explain pigeons’ navigational performance from unfamiliar areas, when combined with the time-compensated sun compass (on sunny days) and perhaps a back-up magnetic compass (on cloudy days).”
Whatever be the explanations, the navigational ability of the pigeons show that they form a far richer picture of the world than average human beings. This is due to their instinctive ability to navigate by the sun, ability to detect magnetic fields using their own inbuilt compass and ability to hear infra-sound. Still humans compensate for their poor sense organs through their intellectual, technical, moral and spiritual abilities. Our awareness that we do not possess some qualities makes us unique. Precisely therein lies our greatness!
(The writer is a professor of science and religion)
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