Hook: Wide-gap, short-shanked, sizes 10 to 16
Body: Egg yarn
How simple is the egg fly? Put it this way: If you’re too clumsy to tie one of these, stay away from all sharp objects, let alone a flowing river. Just fasten an inch of egg yarn to the hook, tease and fluff it out, then shape it into a ball using scissors. Useful colours range from pale yellow to hot pink (the colour of the pictured Egg Fly is, hilariously, Oregon Cheese). If you want to get a little fancier, you can add an extra dot of colour with a marker, or by twisting in a strand of yarn in a different shade.
Egg patterns are so effective that some fly purists consider them cheating, which is a pretty good endorsement. They’re best when dead-drifted near the bottom, often under a strike indicator. These flies are generally associated with steelhead and West Coast salmon fishing, but inland river trout will bite them as well, especially in cold water when other foods are scarcer. Even stillwater rainbows will have a go, and I’ve heard of anglers nabbing such surprise catches as suckers and carp. Wherever you fish it, this is a fly to warm up a cold spring day.