Ear-tipping alerts other volunteers that the cat is sterilized and can be spared the stress of being trapped and anesthetized for a surgical procedure that has already been performed.

The practice, called "ear tipping," is a common method of distinguishing between sterile and fertile cats in order to keep stray populations down. Christopher Furlong/Getty Images ...

When I step out my front door, the first thing I usually see is a feral cat soaking up the sun. Some may view community cats as a nuisance, but these… Animal Life: The Benefits Of Ear-Tipped ...

Q: A new friend invited me to her home, and I was surprised that one of her cats was missing an ear tip. What was left of the ear looked normal, except that it had been cut in a straight line. I&#8… ...

Ever seen feral cats with a distinct cut on the tip of their ears? This isn’t from their tough life on the streets or from fighting, but rather a way to identify that they have been sterilised ...

Stray cats in Guthrie with tipped ears mean they have been trapped, spayed or neutered, then released to help control the feral cat population. Photo: KFOR.

These cats have been ‘ear-tipped’ or ‘notched’. This is a surgical alteration showing that a free-living, feral cat has been spayed or neutered and returned to the streets.