I've had outdoor cats -- at one point two brothers.
One was a complete terror for birds. He'd go after them all, including hummingbirds. Left bits everywhere. Then we lost him due to something bigger and sharper.
The other one couldn't be arsed to hunt anything, until we moved a couple miles into the country and the house had rodents (due to the previous owner feeding birds). Over the course of the first year, he got 25 and I got 2 with traps. Never saw any evidence of dead birds.
One was a complete terror for birds. He'd go after them all, including hummingbirds. Left bits everywhere. Then we lost him due to something bigger and sharper.
The other one couldn't be arsed to hunt anything, until we moved a couple miles into the country and the house had rodents (due to the previous owner feeding birds). Over the course of the first year, he got 25 and I got 2 with traps. Never saw any evidence of dead birds.
So, it varies. By the cat.