On the small streams I frequent, it is hard to fish streamers. It doesn’t seem like an obviously fly choice. However, once you start using them and catching fish they become a staple in your box. Rabbit Hair leeches and squirrel hair leeches work great. On smaller water I find myself fishing them more and more. I cast across, let them sink, swing, and then “jig” them back upstream. Tie some and you will be happy you did.
