It appears that some white storks have put off their trip to Africa to feed on discarded human food, no thanks to the lure of landfills. A new research says feeding on trash dumps instead of migrating makes them more likely to survive the winter.
These findings are yet another show of how humans influence the migration and behavior of animals.
The researchers, reporting their findings in the journal Science Advances, used GPS to track 70 young storks born in Armenia, Poland, Greece, Spain, Russia, Germany, Tunisia, and Uzbekistan.
All white storks in Europe – which breed from Europe to northwest Africa and western Asia – migrated toward south for the winter, but have recently been flying shorter distances to snack on “junk food” or food found on dumps.
In recent decades, increasing numbers have opted to stay closer to their home as they were being drawn to discarded food located in landfills.
"There is some sort of human impact that causes these birds to change their migration strategy," said lead author Dr. Andrea Flack from Germany's Max Planck Institute for Ornithology in an interview.
The scientists discovered that birds from Russia, Greece, and Poland pursued the usual migratory route, flying south as distant as South Africa.
Birds from Spain, Germany, and Tunisia, however, stayed north of the Sahara desert and fed on rubbish dumps, allowing them to get food without the effort of flying long distances. Birds from Armenia flew short-distance, while birds hailing from Uzbekistan stayed home and likely acquired food from fish farms.
Dr. Flack warned that it’s a convenient yet very risky diet for the birds – one whose long-term effects are still unknown.
“The birds can easily eat pieces of plastic or rubber bands, which can get stuck in their throats, and they can die,” said Dr. Flack, adding that something toxic could damage the birds’ health.
Discarded human food, according to the scientist, may be benefitting migratory species now, but long-term consequences still exist.
White storks, for instance, typically eat a wide range of prey – from locusts to frogs to snakes and lizards. These insects can turn into pests once their numbers get out of hand.
“[Storks] provide a useful service.” Flack reminded.
In a comment, Birdlife International’s Stuart Butchart highlighted the decrease in many more migratory species due to habitat loss, breeding pattern changes, and events driven by agriculture, logging, and degradation of coastal mudflats due to land reclamation.
Photo: Bill McChesney | Flickr
