I've used the can for 2 yrs now while bowhunting. I've called in numerous deer this year. I've had better luck when I can see the deer, but it is out of range. In my experience, it works better on young deer.

P.S. This was discussed on the bowhunting forum a while back. It has not been proven that deer make an 'estrous bleat.' The sound from The Can actually mimics a social bleat made by both bucks and does. Therefore, you can use The Can all season.