Your excerpt made me read the article. For those who haven’t or just don’t want to read it, ducks aren’t the only “crazy” birds. Crows and Magpies have been using these spikes and other dangerous human liter as defense from predators. What type of dangerous liter you might ask?

In 1933, a South African museum reported a crow’s nest fashioned from hard-drawn copper, galvanised iron and barbed wire. Nails, screws and even drug users’ syringes have all found their way into birds’ nests.

Some have even ripped metal off nearby factories to build their nests. These birds are on another level.