I've been having some issues with my last three recently bloomed watermelons. Some critter has been biting the tips off. They always leave half the watermelon and don't seem to bother anything else. I have a lot of squirrels, birds, and a few rabbits. The birds are too occupied by eating all of my tomatoes and this doesn't look like their handy work. Anyone know what is doing this and if I can do anything to stop it? I'd like to have more than the one or two watermelons I have currently growing this year.