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Dr. Charles Walcott
on Homing Instincts
Dr. Charles Walcott
Dr. Charles Wolcott is professor and chairman of the Department of Neurobiology and Behavior at Cornell University in Ithaca, New York. He recently was a featured speaker at the invitation of the Lafayette Racing Pigeon Club, and drew a large crowd. His slide talk lasted nearly two hours, and he fielded a great many questions from the audience. What follows is my summary of what he discussed concerning the Cornell studies and the big question of what makes pigeons home.
Dr. Walcott’s research on homing pigeons began at Cornell in 1962. During the high point of the studies in the 1970s and early 1980s, there were from 1,200 to 2,000 homing pigeons in the test group. In addition to the large group, they conducted many experiments on individual birds.
Their data gathering methods included using binoculars to watch the birds as they disappeared from sight following the release. "Vanishing bearings" is the term for the point at which they disappear from sight as they turn toward the direction of home. The researchers also used radio transmitters attached to feathers on the back, so that the researchers could track the birds in a small plane or from the ground via radio transmissions. Most of their experiments were done using a distance of 100 miles.
Dr. Walcott shared a funny story about flying into airspace above Boston’s Logan Airport. As the research plane followed a flock along a path close to the airspace above the airport, the control tower radioed to the plane to find out why it was approaching the airport. The Cornell researchers radioed back that they were just following a flock of pigeons. The air traffic controllers seemed a little skeptical, Walcott said.
Cornell researchers found that vision is not essential for finding the
way home over a long distance.
conclusions were drawn from thousands of hours of tracking the pigeons’
flights home. First, individual birds over a familiar course took a slightly
different route each time. Second, if a bird has been taken away from
a familiar release point and taken to be released from an unfamiliar release
point, he’ll start out in the direction of where he’d go from a familiar
release point, and then make adjustments.
The researchers sometimes masked the birds’ eyes with frosted lenses to see how vision affected the homing ability. They found that the birds come in "high" and sort of "helicopter" down. But most end up near the loft even though their vision is impeded. Thus, the Cornell researchers found that vision is not essential for finding the way home over a long distance.
The researchers did find that to home, the pigeons compare something from the home loft to the release point. To illustrate, Dr. Walcott cited an example of how Cornell birds could not home from a point called Jersey Hill, which raised the question of whether or not there are inherently bad release points. They found, though, that the Jersey Hill release point was difficult only for birds from Cornell raised in Ithaca, New York!
The influence of how magnetic fields affects the homing ability is something that the Cornell researchers explored in depth. They took birds out to places where known magnetic anomalies exist, of which there are many in and around Boston. One especially rich site was one where there is a huge deposit of iron just below ground level, called Iron Mine Hill. The birds could not orient well from this release point. Walcott said you’d expect that the stronger the magnetic anomaly, the worse the pigeons’ disorientation. This was true in Boston. But in Ithaca, the birds homed better from places with magnetic anomalies! Walcott’s only possible conclusions were that either the birds were different, or the magnetic anomalies were different.
To the discussion of the influence of magnetic anomalies, Walcott added that it’s worrisome to scientists when results can’t be duplicated. It implied that birds from one loft were bothered by magnetic anomalies, and birds from another loft are not bothered, even when their training experience is the same. These two different groups of birds had been raised only a mile or two apart. He added that magnetic fields change daily, albeit a small amount, relative to the orientation of the earth to the sun. He added that solar storms cause small problems, generally altering the vanishing bearings slightly.
are extraordinarily sensitive to low frequency sounds, which travel very
suspects, but cannot prove, that some birds learn early on that the magnetic
field is useful in homing. Perhaps the circumstances birds are raised
in determine what cues they use to home.
Walcott emphasized that the birds have a wide menu of homing cues to choose from.
One such cue is the possibility that homing pigeons are born with what Walcott termed a "position finding system." In other words, they have an innate take on what is north, south, east, or west. The Italians, he said, believe that the birds rely heavily on olfactory cues gained from the sense of smell. And Walcott believes that olfaction has something to do with homing, but we don’t understand how it works.
Walcott was asked from the audience if he believes that cellular phones and their transmission towers have an effect on pigeons’ homing. He answered that he doesn’t think they have an effect and that they haven’t been the cause of "smashes." He also said that there’s no evidence that radar disturbs homing pigeons.
Another audience member asked if the Cornell studies concluded that any physical characteristics are associated with good homing ability. Walcott answered that nothing conclusive has come out of those studies. Walcott went on to say that many stories are indicative of individual birds’ abilities. Some birds have great orienting ability. They get close to the loft but cannot find it. Some birds will always head toward a mountain.
Dr. Walcott believes that homing is related to migratory instincts of other animals, which use the same list of potential cues. But different animals weight the cues differently. Pigeons are extraordinarily sensitive to low frequency sounds, which travel very long distances. These low frequency sounds are among the many, many cues that homing pigeons use. But experiments have been conducted plugging the ears of the pigeons, and this has no effect on their homing ability!