Their wing tendons were cut so that they were unable to fly, a process known as pinioning.

Of course, pinioning also made sure that the birds stayed on the lagoon where visitors could admire them.

Pinioning means that birds are less likely to escape from predators such as coyotes, raccoons, off-leash dogs, and even humans.

The official reason for pinioning the Lost Lagoon swans was to prevent the birds from travelling to other places and reproducing, since they aren't native to North America.