Waterlands
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.

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Mayfly
Hatching Now

Gray Drake

Siphlonurus occidentalis

A big swimmer mayfly with a twist: it crawls out to hatch, so the dun barely matters. The evening spinner fall over slow water is the whole event — and it is a good one.

Order
Mayfly
Family
Siphlonuridae
Genus
Siphlonurus
Hook
#10-12
Season · Peak Jun spinner falls
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Gray Drake
Emergence Triggers
Water Temp
52–60°F
Flow
Slow sloughs and side channels
Light
Evenings
Water Type
Slack water, eddies, slough mouths
Lifecycle
How Trout Eat It — Stage by Stage
1
Nymph
May-Jun

Fast-swimming nymphs dart through slow water. Twitch-retrieve a slim gray nymph near slough edges.

Match It
Gray Drake Nymph#10-12
$3.25
Pheasant Tail#12
$2.75
2
Spinner
Evenings, Jun

Clouds of spinners assemble over riffles and fall at dusk. Big fish line up in tailouts — this is the moment.

Match It
Gray Drake Spinner#10-12
$3.25
Para-Spinner Gray#12
$3.25
Cross-Reference
Where This Bug Matters
≋ Waterlands · Hatch data blends USGS gauges, NOAA temps & regional emergence records
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