Garbage dumps may not be very attractive places for us but they sure are for animals. A study published in Science Advances shows how certain groups of storks modified (and significantly shortened) their usual migration routes to pay a visit to landfills.
Andrea Flack is a postdoctoral researcher at the Max Planck Institute for Ornithology. He is researching and tracking the path followed by white storks coming from Germany. These birds have GPS trackers on their back and he decided to get as close as possible to be able to download their flight data. This led Flack to find himself in an open garbage dump in Morocco.
What he discovered is that these birds were stopping there when usually they would fly over the Sahara Desert during winter. "We don't really know yet how much impact it has on their survival" Flack told Live Science. "We can think of it in two ways: on one hand, they have more to eat, and on landfill sites, some populations may increase in size. But we also don't know what kind of long-term effect this waste-feeding has. They might get poisoned or it might have some other long-term negative consequences like diseases".
Digging deeper he found out that same species from other countries all had different behaviors in the last years. Some storks born in Russia follow the original route to South Africa. Meanwhile, other birds situated in Uzbekistan don't migrate at all and don't travel far from their breeding grounds. "This was really unexpected for us because the winter in Uzbekistan is quite cold" Flack said. "We originally thought they would migrate east, toward China, but they didn't. We think it might be connected to some sort of human-related feeding, that they feed on fish farms or some other source coming from humans, but we don't really know".
This change in migration routes might not seem like a big deal, but if birds are eating our trash, they aren't eating other food sources, like agricultural pests. These are things we rely on when we talk about crops so it could result in damaging them and agriculture. Not to mention the change in ecosystem: birds become more used to eating "human food", discarding their usual source of nutriments. In this way they both modify their routes and their habits.
"Migratory animals can have fundamental effects on ecosystems by altering ecological networks, influencing pest control and pollination, or affecting infectious disease dynamics" the authors write in the paper. "Understanding how human actions alter migratory patterns may be the key not only to protecting migratory species but also to maintaining diverse and stable ecosystems".