Broad-bordered Yellow Underwing
Noctua fimbriata
A master of hidden brilliance, the Broad-bordered Yellow Underwing conceals a flash of golden sun beneath its camouflaged wings. This robust nocturnal traveler is a quintessential visitor to the moonlit gardens of Europe and Asia.
Quick Identification
Size
Wingspan of 45–61 mm (1.8–2.4 inches); body length approximately 25–30 mm (1 inch)
Colors
Highly variable forewings ranging from pale ochre and olive-green to dark reddish-brown; hindwings are vivid orange-yellow with a distinctively broad black border
Key Features
- Broad black band on the yellow hindwings occupying nearly a third of the wing area
- Variable forewing color with distinct kidney-shaped markings
- Robust, hairy thorax typical of Noctuidae
- Large size compared to other yellow underwing species
When You’ll See Them
Geographic range
Where Does the Broad-bordered Yellow Underwing Live?
The Broad-bordered Yellow Underwing is native to the Palearctic region, boasting a wide distribution across Europe, North Africa, and Western Asia. It is a common and widespread resident throughout the British Isles, thriving in most temperate environments from the Mediterranean to Southern Scandinavia. While it is most frequently encountered in lowland areas, its range extends through the Caucasus and into parts of the Middle East wherever suitable deciduous cover is available.
Basemap © OpenStreetMap contributors
Behavior
The Broad-bordered Yellow Underwing is a nocturnal moth that exhibits a fascinating behavior known as aestivation. During the hottest parts of the summer, adults may enter a period of dormancy, hiding in cool, dark crevices or thick vegetation before becoming active again in late summer to mate and lay eggs. They are strong fliers and are highly attracted to artificial light sources and fermented sugary substances.
When disturbed during the day, this moth utilizes a 'flash coloration' defense strategy. While its earthy-toned forewings provide excellent camouflage against bark or leaf litter, it will suddenly fly away to reveal its bright yellow and black hindwings. This sudden burst of color is designed to startle predators, giving the moth a split second to escape into deeper cover where it disappears again by folding its wings.
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Camera Tips
To capture the Broad-bordered Yellow Underwing on your backyard camera, you should focus on attracting them to a specific 'stage' using light or scent. Setting up a white sheet with a UV or mercury vapor light nearby is the traditional method, but for a trail camera, placing the unit near a 'sugar patch' is often more effective. Mix fermented fruit, brown sugar, and a bit of ale into a thick paste and smear it on a tree trunk at chest height, then aim your camera at the patch with a macro lens attachment if possible.
Because these moths are highly active at night, your camera's infrared flash is essential. However, to see the diagnostic yellow of the underwings, you may need a camera capable of high-speed color night vision or use a very low-wattage external white light to trick the camera into staying in color mode. Position the camera about 2 to 3 feet from the bait station to ensure the moth fills enough of the frame for the AI to identify it correctly.
Pay close attention to the weather; the best footage is usually captured on warm, humid, and overcast nights with very little wind. Moths are far less active during full moons or heavy rain. During the peak months of July and August, try placing your camera near nectar-rich plants like Buddleia (Butterfly Bush) or Ivy, which provide a natural feeding site for the adults.
Similar Species
Species that look similar or are commonly confused with Broad-bordered Yellow Underwing.
Large Yellow Underwing
The black band on the hindwing is much narrower and it lacks the greenish-ochre tint often seen in fimbriata.
Lesser Yellow Underwing
Significantly smaller in size with a more slender body and different forewing markings.
Lesser Broad-bordered Yellow Underwing
Smaller wingspan (38-48mm) and the black border on the hindwing is not quite as thick.
Frequently Asked Questions
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