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My orange tabby is a happy and friendly indoor (ONLY - THIS IS IMPORTANT AS SHE NEVER GETS A CHANCE TO HUNT ANYTHING - bugs, birds, or anything else) middle-aged female. I have a glass slider in my kitchen that leads to a deck. I had put up an acrylic see-through bird feeder on the outside of the glass with the included suction cups. Eventually the birds started showing up and cat was very interested. She would stalk and hunt as the birds came and went. She would jump up to try and attack (feeder was about 5 foot above the deck) -- obviously never succeeding at the catch but often making a huge racket as she careened through the vertical blinds.
I don't speak cat, so it's hard to tell but it almost seemed like she would be stressed during/after these "hunts".
Is this stressful to her? To be able to see all these critters; to stalk and jump at them - coming within the thickness of double-pane glass from success to no avail time and time again? She has plenty of toys inside - scratch pads, fake mice, balls, towers. It really seemed to be a big interest while it was up, but I am concerned that the fun/excitement of the hunt might be outweighed by never making the catch.
Am I just anthropomorphizing this or is there any evidence that this might actually be harmful?
Another fact is that I adopted her when she was at or around 2 years old. Her history prior was/is unknown so it is possible that she survived by hunting for most of the beginning of her life. I suppose it is possible that having this memory could be cause for stress if were able to hunt/watch but never get a kill.