An intruder recently beat security and broke into the Calgary Zoo, killing a peacock.

A staff member discovered the partially-eaten carcass of the exotic bird in April. The prime suspect? A red fox.

Wild birds can fly onto St. George's Island while skunks, weasels or beavers occasionally find their way into the zoo, said spokesperson Trish Exton-Parder.

But this was an unusual case.

Red foxes — a species found in Alberta — are carnivores and would eat a bird such as a peacock if it came across its path, says a zoo spokesperson. ( Jim Cumming/Shutterstock)

"Having a fox on the grounds is something that just has not happened in my time and so we take it very seriously," said Exton-Parder.

Peacocks are allowed to move freely about the zoo property through much of the year. After the discovery of the carcass, the zoo's seven remaining peacocks were quickly rounded up and placed in an enclosure.

Why would a fox take down a peacock? Red foxes — a species found in Alberta — are carnivores.

"It's definitely on their menu," said Exton-Parder. "I imagine it just crossed the path and took the opportunity so. Unfortunate for the peacock obviously, but it is a natural behaviour for a fox."

It turns out the female fox settled into a non-public area of the zoo and gave birth to a litter of kits.

Zookeepers are monitoring the situation. Until the young ones are a bit older, they'll be left alone.

Exton-Parder said in a few weeks, the fox family will be trapped by zookeepers, taken to a rural area and released.

Until that happens, the peacocks will have to strut their stuff and display their bright plumage inside the safety of an enclosure.