This post got me interested because I mainly hunt Bobcat and am certain that they come in heat in late winter/early spring, and don't see why Bobcat would be any different than Lion or House Cat. I had dinner with my hunting partner who is a Veterinarian and his neighbor that's a retired wildlife biologist and asked what they thought.
They both agree that cats (all) come in season in late winter so the kittens have a full summer to learn survival before winter. They said a cat will continue the estrus cycle every 30 days (approx.) untill they are bred but that seldom happens because they usually get bred the first cycle.
This makes alot of sence to me, and makes me think that Lions, because of their solitary lifestyle, might cycle a few more times before being bred. That would lead some to believe that they come in heat at any time.
I may be completly off base but it's pretty common knowledge that most wild animals give birth in spring for obvious reasons, and stands to reason that cats would be no different. Maybe some of the wildlife biologists on this board will jump in.
Charlie