I've heard about hunting rabbits in months with an R in it. My grandpa and father both refused to let me hunt rabbits until first frost. Usually around November. Even then, in north Texas, you would see the dreaded wolves inside the skin during dressing. Mom refused to cook them, so the hounds got them.
My brother raises show rabbits, they sell for hundreds of dollars each. He says rabbits won't breed when the temp is too high, around 90f I think. He has air conditioning window units in his rabbit barn. Dad said months without R the rabbits are breeding and raising their young.
The shrimpers, mud bug harvesters work during months without an R. I think the reverse is true for oysters.