In article ,
"Ron Herfurth" wrote:

Around here it's called ear tipping because the tip of the ear is cut off.

I think tipping is better than notching. It's easier to see in dim light
(cats are crepuscular, not truly nocturnal as commonly believed--that's
why cats are such good alarm clocks) and it's less likely to be torn in
a fight.

snip

Alley Cat Allies has a sketch showing a fairly large tip being removed,
enough so it would be evident at 10 or 20 feet which may be as close as
you'll ever get to the cat again. It doesn't say anything about which ear
gets tipped.

I wish we as rescuers would come up with a standard for
eartipping/notching. I think it would be very handy (for anal people
like me, anyway) to correspond the snipped ear to the cat's gender.

I keep an Excel spreadsheet record of the cats in my feral colony (now
with digital pictures!), their comings and goings, how much food they
eat, anecdotes, observations and so on (I'm trying to be an autodidactic
naturalist, I guess). Anyway, given the number of animals I care for now
and in the past, it sure would be handy to visually reference their
gender by which ear was cut.