They migrate hundreds of kilometres throughout the ocean with out getting misplaced.
The Arctic tern, for example, spends summer season within the UK, then flies to the Antarctic for the winter.
But, scientists are nonetheless uncertain precisely how birds carry out such excessive feats of migration, arriving in the proper place yearly.
In response to new analysis, scent performs a key position when birds are navigating lengthy distances over the ocean.
Researchers from the colleges of Oxford, Barcelona and Pisa quickly eliminated seabirds’ sense of scent earlier than monitoring their actions.
They discovered the birds may navigate usually over land, however appeared to lose their bearings over the ocean.
This implies that they use a map of smells to seek out their approach when there aren’t any visible cues.
Earlier experiments had steered that eradicating birds’ sense of scent impairs homing means. Nonetheless, some had questioned whether or not sensory deprivation would possibly impair another operate, comparable to the flexibility to seek for meals.
”Our new research eliminates these objections, that means it is going to be very troublesome in future to argue that olfaction just isn’t concerned in long-distance oceanic navigation in birds,” mentioned research researcher Oliver Padget of Oxford College’s Division of Zoology.
He mentioned seabirds had been amongst “nature’s biggest navigators”, discovering their approach over large distances.
The researchers studied 30 Scopoli’s shearwaters dwelling off the coast of Menorca. The birds nest within the Mediterranean, however spend the non-breeding season within the Atlantic, together with areas off the west coast of Africa and the east coast of Brazil.
A few of the birds had been made to quickly lose their sense of scent via nasal irrigation with zinc sulphate; one other group carried small magnets; and a 3rd group acted as a management.
Tiny GPS units had been connected to the birds as they nested and incubated eggs on the rocky shoreline.
The birds had been then tracked as they went about their every day enterprise.
The birds with no sense of scent made profitable foraging journeys to the Catalan coast and different distant websites. Nonetheless, they’d issues navigating once they had been out of sight of land.
Once they approached land, their orientation improved, suggesting birds use an olfactory map when there aren’t any visible landmarks.
The query of how birds navigate and carry out long-distance migrations has lengthy been of scientific curiosity.
Birds’ sense of the Earth’s magnetic subject and their olfactory talents are among the many elements thought to play a job.
The analysis is printed within the journal Scientific Reviews.
Observe Helen on Twitter.