Ooh! Thats a hard one Staffan,at times of the year there can be 50 in 100 HA, at other times there can be 2 in the same area.
When the blackberry leaves turn brown the deer come into the creek systems where the berries are thick and flog them for a month,they mob up then and then disperse when the berry bushes change again.They only eat the leaves and not the berries.