River Intelligence · Entomology
Read the Water. Match the Hatch.
Every river has an entomological fingerprint — the bugs it grows, when they hatch, and how trout eat them. Learn the bugs, cross-reference live flows, and fill your box before you go.
NEW TO BUGS?Four insect orders feed 90% of trout. Start with Bug School to learn the lifecycle, then come back and browse.
Blue-Winged Olive
Baetis tricaudatus
Blue-Winged Olive
Mayfly
#16-22
Baetidae
JAN
PEAK · MAR-MAY / SEP-NOV
DEC
Pale Morning Dun
Ephemerella excrucians
Active Now
Pale Morning Dun
Mayfly
#14-18
Ephemerellidae
JAN
PEAK · JUN-AUG
DEC
Green Drake
Drunella grandis
Active Now
Green Drake
Mayfly
#10-12
Ephemerellidae
JAN
PEAK · JUN-EARLY JUL
DEC
Trico
Tricorythodes explicatus
Active Now
Trico
Mayfly
#20-24
Leptohyphidae
JAN
PEAK · JUL-SEP MORNINGS
DEC
Mahogany Dun
Paraleptophlebia bicornuta
Mahogany Dun
Mayfly
#12-14
Leptophlebiidae
JAN
PEAK · SEP-OCT
DEC
Sulphur
Ephemerella dorothea dorothea
Active Now
Sulphur
Mayfly
#16-18
Ephemerellidae
JAN
PEAK · LATE MAY-JUN EVENINGS
DEC
Small Western Red Quill
Rhithrogena undulata
Active Now
Small Western Red Quill
Mayfly
#12-14
Heptageniidae
JAN
PEAK · JUN-AUG
DEC
Western March Brown
Rhithrogena morrisoni
Western March Brown
Mayfly
#12-14
Heptageniidae
JAN
PEAK · MAR-APR
DEC
Flav
Drunella flavilinea
Active Now
Flav
Mayfly
#14-16
Ephemerellidae
JAN
PEAK · LATE JUN-JUL EVENINGS
DEC
Gray Drake
Siphlonurus occidentalis
Active Now
Gray Drake
Mayfly
#10-12
Siphlonuridae
JAN
PEAK · JUN SPINNER FALLS
DEC
Callibaetis
Callibaetis ferrugineus hageni
Active Now
Callibaetis
Mayfly
#14-16
Baetidae
JAN
PEAK · JUL-SEP, LATE MORNING
DEC
Mother's Day Caddis
Brachycentrus occidentalis
Mother's Day Caddis
Caddisfly
#14-16
Brachycentridae
JAN
PEAK · LATE APR-MAY
DEC
Spotted Sedge
Hydropsyche cockerelli
Active Now
Spotted Sedge
Caddisfly
#14-16
Hydropsychidae
JAN
PEAK · JUN-SEP EVENINGS
DEC
October Caddis
Dicosmoecus gilvipes
October Caddis
Caddisfly
#8-10
Limnephilidae
JAN
PEAK · LATE SEP-OCT
DEC
Little Black Caddis
Brachycentrus americanus
Little Black Caddis
Caddisfly
#16-18
Brachycentridae
JAN
PEAK · APR-MAY
DEC
Salmonfly
Pteronarcys californica
Salmonfly
Stonefly
#4-8
Pteronarcyidae
JAN
PEAK · LATE MAY-JUN
DEC
Golden Stone
Hesperoperla pacifica
Active Now
Golden Stone
Stonefly
#8-10
Perlidae
JAN
PEAK · JUN-JUL
DEC
Skwala
Skwala americana
Skwala
Stonefly
#10-12
Perlodidae
JAN
PEAK · FEB-APR
DEC
Yellow Sally
Isoperla mormona
Active Now
Yellow Sally
Stonefly
#14-16
Perlodidae
JAN
PEAK · JUN-AUG
DEC
Midge
Chironomidae spp.
Midge
Midge
#18-26
Chironomidae
JAN
PEAK · NOV-MAR (WINTER STAPLE)
DEC
Blue Quill
Paraleptophlebia debilis
Blue Quill
Mayfly
#16-18
Leptophlebiidae
JAN
PEAK · APR-MAY / SEP-OCT
DEC
Brown Drake
Ephemera simulans
Active Now
Brown Drake
Mayfly
#10-12
Ephemeridae
JAN
PEAK · JUN EVENINGS
DEC
Pink Lady
Epeorus albertae
Active Now
Pink Lady
Mayfly
#12-14
Heptageniidae
JAN
PEAK · JUL-SEP EVENINGS
DEC
Spruce Moth
Choristoneura freemani
Spruce Moth
Terrestrial
#12-14
Tortricidae
JAN
PEAK · AUG
DEC
Terrestrials
Orthoptera, Hymenoptera, Coleoptera
Active Now
Terrestrials
Terrestrial
#8-16
Various
JAN
PEAK · JUL-SEP
DEC
Scuds & Sowbugs
Gammarus, Hyalella, Asellus
Active Now
Scuds & Sowbugs
Crustacean
#14-18
Gammaridae, Asellidae
JAN
PEAK · YEAR-ROUND
DEC
Mysis Shrimp
Mysis diluviana
Mysis Shrimp
Crustacean
#16-18
Mysidae
JAN
PEAK · WINTER, ON DAM RELEASE
DEC
Worms & Eggs
Oligochaeta / salmonid ova
Worms & Eggs
Other Food
#12-16
Various
JAN
PEAK · RUNOFF AND SPAWN WINDOWS
DEC
Baitfish & Sculpin
Cottus spp. and forage minnows
Baitfish & Sculpin
Other Food
#2-10
Cottidae, Cyprinidae
JAN
PEAK · SPRING AND FALL
DEC
≋ Waterlands · Hatch data blends USGS gauges, NOAA temps & regional emergence records
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