(KRON) — Some people demonstrate their love for their significant other by leaving a padlock – or a “love lock” – on a fence. The National Park Service says you should not do that.

“Love is strong, but it is not as strong as our bolt cutters,” the NPS said.

According to the NPS, love locks are a form of graffiti and are considered littering.

People who leave love locks also often carve the couple’s initials into the lock before throwing the key away. This is where danger can lie, the Grand Canyon NPS said.

Rare and endangered condors inhabit the Grand Canyon, and they are drawn to shiny things. When lovebirds chuck their key into the canyon after leaving the lock on a fence, a real bird might swallow it.

“Condors love shiny things. They will spot a coin, a wrapper, or a shiny piece of metal, like a key from a padlock that has been tossed into the canyon and eat it. Condors are not meant to digest metal and many times cannot pass these objects,” the National Park posted on Facebook.

The post included an X-ray of coins lodged in a condor’s digestive tract. The park said the bird had to have an operation and could have died.

Love locks are not specific to the Grand Canyon. In fact, they can be seen in the area around the Golden Gate Bridge as well.

While condors are rarely seen in the Bay Area, the Grand Canyon recommends not discarding keys regardless of where you are.

“Do your part to not contribute to these bad habits and inform others of what can happen to the wildlife if these behaviors continue,” it said.