They are easily targetted in the spring when they come in to spawn I guess. They are extremely aggressive. It just so happens it coincided with shed hunting and everything else. We tied flies that were a pain in the arse to throw, with tails that were 8 inches or so long. It brings a new meaning for slogging flies. They had a popper design for the head. Used lots of material. I'll have to see if I have any left.