Nebbie does that, when she sees birds or squirrels or something that she wants to go hunt.
One of the cats at the sanctuary has a meow that sounds more like chirping. Her name was Tabitha, but we already have at least half a dozen Tabithas in our database, so the supervisor wanted to rename the cat. So for a couple days I was calling her Birdie...but then figured she's not a bird, just sounds like one - then I called her Chirpie.
For anybody living in Utah (or heck, anywhere!) that wants an orange tabby that chirps, she's only $25! LOL