Selecting for strikes

Between 1990 and 2007, the number of wildlife strikes has tripled from 0.527 to 1.751 per 10,000 jet flights.

Growing populations of birds and humans in the same areas have put the species on a collision course in the air that's almost always deadly for the birds and severely hazardous, if not fatal, to humans, too. Human developments and bird-restoration programs have created new ecological niches that some bird species have jumped in to fill.

In particular, the Canada goose population is proving particularly problematic. Their numbers have ballooned to more than 3.5 million [in the U.S.], and the birds don't migrate, they stick around our cities. Many of the geese along the eastern seaboard are closer to feral than wild. After their forebears were nearly hunted to extinction, many domesticated birds were released into the wild (pdf), creating a specific population of geese uniquely suited to the "current landscaping techniques" of our urban and suburban landscapes.

-- Birds, Humans Increasingly on Collision Course