I have 3 happy (ex-)male cats, all just over a year old. I love them dearly. They spend probably 75% of their time indoors; I don't let them outside at night (raccoons) or when I'm not here. They adore exploring outdoors, though, so I do let them run free as often as I can. My problem is that I also love the birds; there are many here at my idyllic spot on the Oregon coast. But one of my dear boys has discovered he's proficient at catching HUMMINGBIRDS! This is breaking my heart; wish I could come up with a way to protect the birds! My cats all have collars with bells; but this doesn't seem to help. Aside from keeping the cats inside ALL the time, which I am loath to do, does anyone have other techniques that have worked???