B. G. Thomson/SCIENCE PHOTO LIBRARY
The migration of thousands of kilometres across the sea, without getting lost.
The Arctic tern, for example, spends the summer in BRITAIN, and then flies to the Antarctic for the winter.
However, scientists are still uncertain exactly how the birds accomplish such feats extremes of the migration, arriving in the right place, every year.
According to new research, the sense of smell plays a key role when birds are navigating long distances over the ocean.
The researchers from the universities of Oxford, Barcelona and Pisa temporarily removed sea-birds’ sense of smell before to follow their movements.
You have found the birds are able to navigate normally on the ground, but seemed to lose their bearings on the sea.
This suggests that the use of a map of smells to find their way when there are no visual cues.
Previous experiments had suggested that the removal of birds’ sense of smell alters the ability of homing. However, some had questioned whether the sensory deprivation may impair other functions, such as the ability to search for food.
“Our new study eliminates these objections, which means that it will be very difficult in future to argue that the sense of smell is not involved in the long distance oceanic navigation in birds,” said study researcher Oliver Padget of the University of Oxford Department of Zoology.
He said that the seabirds were between “nature great navigators”, they find their way to enormous distances.Magnetic compass
The researchers studied 30 Scopoli’s shearwaters that live off the coast of Menorca. The birds nest in the Mediterranean, but spend the non-breeding season in the Atlantic, including areas off the west coast of Africa and the eastern coast of Brazil.
Some birds were made to temporarily lose their sense of smell through the nasal irrigation with zinc sulfate; another group carried small magnets; and a third group acted as a control.
Small GPS devices were attached to the birds are nested and incubated eggs on the rocky coast.
The birds were then tracked as they went about their daily business.
The birds without the sense of smell, foraging success, trips to the Catalan coast and other distant sites. However, they had problems of navigation when they were out of sight of land.
When he approached the earth, their orientation has improved, suggesting that birds use an olfactory map when there are no visual references.
The question of how birds navigate and perform long-distance migration has long been of scientific interest.
The birds sense the earth’s magnetic field and their ability to smell, are among the factors thought to play a role.
The research is published in the journal Scientific Reports.
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