Birds just aren’t migrating the way they used to. And why should they? Climate change has made winters warmer, meaning they don’t need to travel as far in order to make it through the brutal temperatures.
But it’s not just climate change that’s giving birds—particularly white storks—reason to stay. New research published in Movement Ecology this week suggests that land fills provide enough food for the birds to stick around throughout the year. What that means, though, is that they’re literally eating garbage.
“It’s gross, actually,” Aldina Franco, an ecologist at the University of East Anglia in Norwich, England and lead author of the study, told Quartz. “When a truck arrives, they all congregate behind it. Sometimes they eat computer parts, but what they are really looking after are our leftovers.”
Franco explained that ordinarily, white storks live all over Europe in the summer, breeding months, and migrate to either southern Europe or sub-Saharan Africa over the winter. They typically eat a diet of small insects or spiders, though they also have been known to eat crayfish in rice fields.
Now, however, Franco says that of the population of about 14,000 white storks in Portugal, an increasing number are becoming residents of the areas near landfills. She and her team had been tracking the movements of over 50 of these storks in Portugal, and for this study looked at the movements of 17 birds they knew had set up colonies near the landfills. They found that even with their unusual new dietary patterns, storks that stayed over the winter had the advantage of starting to breed earlier in the season and raise more chicks per nest. “The good consequences of having extra food override the bad ones [of the diet],” she said. Franco added that in this particular study, she and her team didn’t look at the effects of consuming atypical food.
Until these landfills are gone, that is. The European Union Landfill Directive mandates that all states in the EU phase out their landfills entirely by 2018. Franco does not know what will happen to the birds in the coming years as the landfill sites close over time. “Probably these birds will struggle,” she said, adding that she expects they will either have to start migrating once more, or they will die.