When Kitty FC used to go outside many moons ago, if the back door was shut
she used to fling herself at it to make a huge bang so I knew she was there
and wanted to come back in.  She cannot meow, never has done.  She opens her
mouth but only the tiniest little sound comes out.  Meh.  Not much use for
alerting the meowmie.
It's a stable type door with windows in the top part and in her younger days
she would not only bang the door but would hang off the bottom part with her
claws and peer in if she didn't get an immediate response.
Imagine my surprise just now when that old familiar "let me in before the
door comes off it's hinges" bang came.
Yes, the nicer weather we've been having had obviously tempted her to go out
for a stroll (I thought she was upstairs, snoozing..) and she hasn't
forgotten what to do to get back inside and is still strong enough to do it.

She amazes me.  She is well over 20 and I don't remember that she's gone
outside for 2 years or so.  She always liked to be semi-feral so I won't
stop her if she wants to have a bit of a stroll around her garden where once
no cats dare come for fear of her.  She does have some cognitive impairment
now though, I am very aware of this.  I have to balance what she wants to do
versus what I think is safe.
Banging the door tonight means she is safe for the moment.

Tweed