Lesser yellow underwing
Its bright yellow hindwings stay completely hidden until it flies, flashing into view only when a predator startles it into motion.
| Where | Gardens, woodland and open countryside |
|---|---|
| Size | 37 to 45 mm wingspan |
| When | June to October |
This moth has variably coloured brown forewings, from pale sandy tones to darker forms, and hindwings that are yellow with a black band near the edge, visible only in flight or when disturbed. Wingspan is about 37 to 45 mm.
The caterpillars overwinter while still small and resume feeding on a wide range of herbaceous garden and hedgerow plants the following spring, before the adults emerge in a single generation later that year.
Traits
Habitat
Garden
Colour
Brown, Yellow
Active
Night
To people
Harmless
Activity through the year
Often confused with
The lesser broad-bordered yellow underwing runs slightly smaller on average, at 30 to 40 mm against the lesser yellow underwing's 37 to 45 mm, and needs close examination of the hindwing band width to separate reliably.
Questions
Is the Lesser yellow underwing dangerous to people?
The Lesser yellow underwing is harmless to people.
When can you see the Lesser yellow underwing?
The Lesser yellow underwing can be seen from June to October, at night.
Plate retouched from a photo by Ben Sale from Stevenage, UK, CC BY 2.0, Wikimedia Commons Licence
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Butterflies and moths›Owlet moths›Noctua
Last updated 2026-09-26. Every entry is checked against published sources.