Much has been written and studied regarding the world’s bird populations in an effort to identify how and why birds act the way they do, particularly during migration.
As one of the most impressive feats in the animal kingdom, researchers have long been fascinated by our feathered friends’ ability to navigate long distances, often at night, as they head to their southern wintering grounds.
From astronomy to the earth’s magnetic field, there are many theories out there to suggest how birds make these long journeys, but as research continues, ornithologist and other researchers continue to push the envelope to uncover more about this unique behaviour. In a large-scale study, researchers with Oxford University’s Department of Zoology designed an experiment that would test the olfactory response among seafaring birds as they migrate, to determine what, if any affect their sense of smell had on their migration.
Capturing and fitting 32 Scopoli’s shearwaters; a long-distance migrating European seabird, with GPS tracking units, Oliver Padget and his team divided the birds into three groups. The first group was a control group, one without any outside influences, the second was fitted with magnets and the third, a scentless group.
It was this third group that would be the basis of the study, seeing each of the subject birds receiving a nasal irrigation of zinc sulfate to cause them to temporarily lose their sense of smell.
Monitoring the birds for a month as their raised chicks and foraged for food, the presence of magnets or the loss of their sense of smell had zero impact on the birds’ day-to-day life. When it came to long-range foraging expeditions, particularly over large expanses of water, that is when the data suddenly became interesting.
The flight patterns recorded over bodies of water were exponentially different in nature. While both groups did manage to successfully find their way, it was the birds without their olfactory senses that seemingly had a more difficult time returning back to their colony.
The birds that had their sense of smell inhibited took to more linear pathways and did not seem to stray from their path while over the water. Those with their olfactory senses in tact, however, confirmed previous studies that found that birds will use their sense of smell to create olfactory maps over large bodies of water to aid them in navigation.
“Our new study eliminates [objections to past work], meaning it will be very difficult in future to argue that olfaction is not involved in long-distance oceanic navigation in birds,” Padget told the BBC.
The research does not, however, necessarily translate to smaller songbirds, who unlike larger seafaring birds, are without the large olfactory brain structure related to smell.
Read the full study here.