Leeches in the swamp

This is the story of my father that have taught me to wear boots when going camping. He and 4 companions were hunting birds and decided to do a cookout by the shallow river bank. As usual, the roasted birds was a banquet that late afternoon. They were engrossed in their conversation that they failed to notice the leeches crawling on their feet. One of his companions noticed it because the leech was already attached to his leg. And since my father was wearing his boots, he was safe from the attack.