Well-meaning humans keep moving owls, but the side effects are hitting entire ecosystems hard.

Owls show up in all kinds of unexpected places these days. Some are moved on purpose to control pests. Some hitch a ride on climate shifts. Others escape from captivity and quietly stake out new territories. It all sounds harmless until the ripple effects start showing up. Native species lose ground fast. Hybrid owls complicate conservation. And entire food webs shift in ways no one predicted.
This is not a theoretical problem anymore. The barred owl’s expansion into the Pacific Northwest is one of the most studied examples, but other cases are popping up across Europe and North America. Little owls introduced to Britain, barn owls released to vineyards, eagle owls reintroduced to parts of Europe — the list keeps growing. The trouble is, owls are highly efficient predators. When they land in ecosystems that were not designed to handle them, things can unravel fast. Here is what tends to happen next.