How do birds fly long distances? This complex issue has been the subject of many controversies and controversies among scientists for decades, and the potential factors include the Earth's magnetic field and bird's sensation.
Scientists from the Oxford University, Barcelona and Pisa have shown in a new experiment that sensation is almost certainly a key factor in navigating on large overseas distances, thereby eliminating existing doubts in this hypothesis.
The research was published in the journal Scientific Reports .
"Oceanographic navigation is likely to be an extreme challenge for birds, given the long distances, the changing environment and the lack of stable orientation," said study leader Oliver Padget, a PhD candidate at the Oxford Zoology Department. "Previous experiments focused on the physical displacement of birds combined with some form of sensory manipulation, such as magnetic or olfactory deprivation. Evidence from these experiments suggested that removing the bird's feelings of hay made it harder to return home, while the removal of magnetic sensation gave rise to unpredictable results. "
"But critics have always wondered if the birds behaved as if they were not artificially moved, as claiming that sensory deprivation or deprivation senses does not necessarily disturb the bird's navigational ability, but perhaps some other aspect, such as motivation for return home or ability search for food. "
"This study eliminates those objections, which means that in the future it will be very difficult to advocate that the smell of smell is not involved in oceanic long distance navigation."
In this experiment, scientists were observing the movements and behavior of 32 free-range birds on the Spanish coast. Birds are divided into three groups: one group temporarily removed the sensation by injecting zinc sulphate through nasal openings, the other group has small magnets attached, and the third group is controlled, ie unchanged conditions. Miniature GPS devices are attached to birds as they nest at the shore. Instead of moving or relocating, they were tracked while doing their usual flight to look for food.
All the birds went on a flight looking for food as they did, and they came back to change the incubation period with their partners. Thus, removing the smell of birds in birds did not significantly affect their motivation for return or ability to successfully search for food.
However, although the birds with temporarily removed snout have successfully crossed the Catalan coast and other distant areas, they have shown significantly different orientation behavior from the control group during the overseas return journey. Instead of good orientation towards the house at a time when there was no land in sight, they came to a surprisingly flat but poorly oriented flight over the ocean, as if following a compass indicating the way of return, but not in line with their current position
Their orientation improved when land is approaching, suggesting that birds use their olfactorial maps when they are out of sight, and then are able to find a path using known environmental features.