Here in NW Iowa I've had my best luck from mid February through most of the month of March. Just as Lady Forge mentioed, I've also had my best luck around thick bedding areas and trails to feeding areas. fence crossing are also good. (The impact when the deer jumps the fence will sometimes jar a loose antler off.) South facing slopes where the deer often bed in the sun and out of the wind are a good starting place in my opinion.

Jon
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