Animals become easier to hunt during mating season.
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If you want to preserve the local game resource, you do not hunt them during at season, absent a government agency setting rules. Also remember during that time humans were few and animals were plentiful and very dangerous to hunt.
No...
hunting the males ...of which there are always an excess... reduces both competition between males and the stress on the females in breeding season, making the females more successful in rearing young. When there are too many males there is more fighting, more injuries, and of course, nearly constant pursuit and harassment of females, which limits the amount of grazing they can get in a day, and can leave them underweight.