We have trouble with a cat from down the street...
We have a nice little koi pond w/ waterfall in the yard and the birds like to bathe and drink the water. The neighbors cat was catching our birds and leaving the remains.
Cat didn't care that Tink would come out...cat was bigger.
We found one of the boys old super soaker water gun...it goes at least 30 ft....the face on that cat was priceless! It only took a couple of times getting blasted for the cat to go elsewhere.
(Works on Possoms, too)