A group of researchers found that white storks in Spain and Portugal apparently completely forgot about their annual winter migration to gorge on trash in landfills. Apparently, the strange phenomenon is due to the fact that the big birds may have developed a full-blown junk-food addiction.
Aldina Franco of the University of East Anglia and lead researcher involved in the study noted that it is highly unusual for storks to skip their annual trip to their wintering grounds in Africa. She added that before the 1980s there was no such thing as a staying bird in winter.
But after that date, more and more storks forgot about their annual trip, and now the number of these birds reached unprecedented levels. For example, in Portugal alone though stork population jumped from 1,187 to 14,000 individuals in just two decades, 80 percent of the birds that decide to ditch migration live in the country’s landfills.
Study authors explained that birds no longer see migration necessary for survival as they have a stable and reliable food source just under their nose.
The team tracked 48 storks through GPS loggers. The data showed that for several years the birds stayed in the landfill sites they now call home all year round.
Plus, their behavior was also greatly altered because of their life in the landfills. For instance, many birds that had their nests in the landfill would only leave their nests to grab food. Other birds living farther would travel up to 30 miles to feast on garbage.
Andrew Farnsworth, a bird researcher with the Cornell Lab of Ornithology who did not participate in the research, was thrilled to learn how the large birds exploited new resources. Farnsworth was also eager to find how living in a landfill would further affect stork population in the two European countries.
Franco noted that skipping migration may have some benefits. For instance, storks can reproduce easier now since they have their nests at their disposal and a constant food source. So they are ready to breed when they find a mate.
But researchers are puzzled by the storks that are not skipping migration, and they plan a separate study.
Nevertheless, storks are not the only animals that canceled their migratory trips for good. The turkey vulture and Canada goose are two other examples.
But white storks are not staying at home just because they have enough food to eat year-round. The climate is now milder due to climate change, researchers explained, so their life is easier in winter.
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