As we passed the solstice our bees hopefully are approaching their greatest size with a huge amount of wonderful honey/beebread/brood smells wafting out of the hive. Bears have an excellent sense of smell. Conservative estimates range from 1-2 miles, with some estimates are much farther, in upwards of 20 miles... I saw the most healthy beautiful big black bear a few days ago. It had just come from a sniff around my apiary. That said, check your electric fence regularly to make sure it is free of overhanging weeds and branches that could ground out your fence reducing or eliminating it's effectiveness. Check the voltage on the fence to make sure your fence charger is delivering the required jolt. Do not bait the wire with a titbit that may act as a reward. Check your charger battery for full charge if you have a solar charged fence. Once a bear finds food, it will come back, you can count on it.