Actually the difference in sounds, jack is usually more raspy, is a good thing. It will sometimes evoke a response when others won't. The same goes for snowshoe hare, it works. Your swamp rabbits are likely similar to the jack as they are much larger than most cottontails... I've never heard a swamp rabbit distress but I would imagine it to be very loud and raspy, but then again maybe not. Every animal is unique.
Predators respond to distress of any kind. They are after an already hurt or injured easy meal! Almost any "hurt" sound will work!
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