There are many species of blue-winged olive mayflies. Hatches begin as early as late September and continue until April, with the best activity in February and early March. Those fly fishermen that only pick up their rod in the late spring and summer months really miss some fine fishing.

The scientific name is genus Baetis (pronounce beet-us) and Diphetor but they are more commonly known as BWOs, blue wing or tiny olives. Hatches normally start just after lunch. Some of the best hatches are on days when it is drizzling. Search out back-eddies on the river. This is where you can normally find blue-winged olive circle endlessly around and around. They like the air currents and this is where you will find the trout ready to suck them down.

This fly also works well in slow run stretches of water. Use your eyes and hunt the swarms. The Pheasant Tail Nymph and Gold Ribbed Hare's Ear nymphs are ideal imitations for the blue-winged olive's early stages. Drift them near the bottom any day between September to April that is if your part of the world is not covered in ice.