A fox runs past the door of 10 Downing St. on Jan. 13, 2015, in London. Urban foxes have been a major nuisance for many years in London, though some residents found a recent napping fox in Notting Hill to be quite cute. AFP/Getty Images

A fox was discovered napping on a second-floor windowsill in London's Notting Hill neighborhood on Thursday. Residents across the area who wondered how it got up there received a theory from nearby resident Rachel Johnson, sister of Boris Johnson, the mayor of London.

"Urban foxes are notorious for being bold opportunists – but the residents of the Tory stronghold of Notting Hill in London were still surprised," reported British newspaper the Independent.

Rachel Johnson said the neighborhood had recently been overrun with foxes who seemed to "own the place." She said she felt less animosity toward the sleeping creature in comparison with his furry brethren that had run amok in local gardens. "Luckily no one decided to shoot it!" she told the Evening Standard newspaper. "It was rather a sitting duck there on the ledge," she said.

Most foxes only come out at night. Curled up on a ledge in the middle of the day, however, the fox could easily have been mistaken for a household cat. Foxes have made their homes in London since the 1930s and authorities estimate their number in the city to be somewhere in the tens of thousands. Residents are warned not to feed the foxes and to call the police to shoot them if they pose a threat.

Foxes are a nuisance but not a danger to most Londoners. On two occasions in the past five years, however, sleeping babies have been mauled by foxes that came in through the window. In one instance, the fox bit off a baby's finger.

The fox in Notting Hill appeared quite peaceful. “It must have got up via the scaffolding on the house next door," said Johnson.