Mystery of disappearing homing pigeons finally solved
Washington, January 31 : Homing pigeons are usually remarkably efficient navigators, however, on rare occasions, things go drastically wrong and they get lost.
When Jon Hagstrum of the US Geological Survey read in his local newspaper about two races when pigeons had been lost in 1998, it reminded him of a lecture by Bill Keeton that he had heard years before as an undergraduate at Cornell University.
Keeton had been studying how birds successfully navigated from distant and unfamiliar release sites. However, the birds almost always had problems selecting the correct bearing home when released from three local sites.
According to Keeton, pigeons released at Castor Hill and the town of Weedsport consistently took the same wrong turn when they departed. Meanwhile, birds that were released from Jersey Hill tended to head off in random directions, but with one exception: all of the birds that departed from the hill on 13 August 1969 returned home successfully having taken the correct bearing.
Explaining that Keeton had already ruled out the possibility of a disturbance in the local magnetic field, Hagstrum recalls, 'Bill asked if we geologists had an idea what might be going on at these sites'.
Several years after Keeton's lecture, Hagstrum came up with a possible solution to the problem when he read that pigeons could hear incredibly low frequency 'infrasound'.
Explaining that infrasound and #65533; which can be generated by minute vibrations in the planet surface caused by waves deep in the ocean and #65533; travels for thousands of kilometres, Hagstrum wondered whether homing pigeons are listening for the distinctive low frequency rumble of their loft area to find their bearing home.
In which case, birds that could not hear the infrasound signal, because the release site was shielded from it in some way, could not get their bearing and would get lost.
Hagstrum decided to investigate the meteorological conditions on the days of unsuccessful releases to find out if there was something in the air that could explain the pigeons' disorientation.
He discovered that Keeton's lost pigeons could not hear the infrasound signal from their home loft because it was diverted by the atmosphere.
Explaining that the birds must use the loft's infrasonic homing beacon to get their bearing before setting the direction for their return flight according to their sun compass, Hagstrum said, "I am a bit surprised that after 36 years I finally answered Bill Keeton's question to the Cornell Geology Department", adding that he is particularly pleased that he was able to use Keeton's own data to solve the mystery.
He publishes his discovery in The Journal of Experimental Biology.