Baetis or Blue-winged Olive Mayflies.

What is the Baetis or Blue-winged Olive Hatch? Baetis aka Blue winged Olive Entomology.

by Mike RyanMarch 21, 2019 in Fly Hatches

The Baetis mayfly, also known as the blue-winged olive, little olive, little blue dun or BWO mayfly typically hatch in the spring and the fall, but are available as trout food all year around, and are one of the most abundant mayflies, making appearances in nearly every moving body of water. These small, olive bodied flies with grey to slate wings range in size from #16 - #22, and typically, but not exclusively, hatch on overcast days. 

Baetis Nymph

Baetis Nymph: The nymph lives under rocks, stream plants and in decomposing vegetation.  They are good swimmers, so can move around by crawling or swimming.

A few of our Baetis Nymphs:  See All Baetis Nymphs

Pheasant Tail
Poxyback Baetis Nymph
Crystal BWO Beadhead Nymph
Two Bit Hooker - Dark Olive
Panty Dropper Nymph - Baetis
Mighty May - Baetis

Baetis Emerger:  When mature, the nymph lets go of the river bottom, swimming upward in short bursts. Water’s surface presents a barrier that is difficult and time consuming for the nymph to penetrate.  Trout recognize this stage of the Baetis hatch as an effortless meal, so fishing a Baetis emerger just below the surface is often very productive.  Once the emerging nymph breaks through the water surface, their exoskeleton splits apart, and the adult or dun struggles out.  A decent percent of these emergers get stuck trying to crawl out of the exoskeleton, and are called cripples.  The emerger and cripple are completely defenseless, and are effortless meals for trout. 

A Few Baetis Emergers:  See All Mayfly Emergers

Mayhem BWO Emerger
Jujubaetis Flashback
Last Chance Cripple - Baetis
Baetis Emerger Dry
Cripple Blue-Winged Olive
RS2 Grey
Baetis or Blue-winged Olive Adult Mayfly

Baetis Adult:  After exiting the exoskeleton, the adult rides on the water and dries its wings, then flies off as a dun or adult mayfly.  The dun or adult mayfly usually fly toward vegetation along the bank, and only hours later, molt into a spinner, or a sexually mature mayfly.  Spinners return above the river, flying in swarms and mate.  Some species of females will return to the water, lay eggs on submerged objects in the river, while others will fly along the water surface while depositing eggs into the water.  Once finished, the female dies with its wings flat on the water, and drifts down the river.

A Few of the Adult Baetis Mayflies we offer:  See All Adult Baetis Mayflies

Perfect Baetis Mayfly
Blue-winged Olive - Hatchmaster
Blue-winged Olive Extended Body
Parachute Blue-winged Olive
Parachute Blue-winged Olive Loopwing
Hackle Dun - BWO

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