How to identify the American Dagger Moth
The American Dagger Moth is a fairly large owlet moth with a wingspan of about 2 to 2.5 inches. The forewings are pale to medium gray, finely peppered with darker scales, and crossed by wavy lines. Its name comes from the small black dagger-shaped dashes near the inner (trailing) margin of the forewing, the clearest field mark for separating it from other gray noctuids. The hindwings are plainer and whitish-gray. At rest it holds its wings rooflike over the body, giving the classic bark-mimic look that helps it disappear against tree trunks.
Where it lives
This is an eastern species tied to hardwood forests, wooded suburbs, and parks. In the open GBIF records behind this tool, the heaviest sightings come from New York, Virginia, North Carolina, New Hampshire, and Vermont, but it ranges broadly across the eastern and central US and into eastern Canada. Anywhere you have mature maples, oaks, and other broadleaf trees, you have likely got American Dagger Moths nearby.
When it flies
Peak adult activity runs July, August, and September. You may catch a few stragglers on the shoulders of that window, but late summer into early fall is when this moth shows up most at lights. That timing lines up with prime general mothing season and with events like National Moth Week (July 18 to 26 in 2026). You can check what is likely flying tonight near you for any date in that span.
Caterpillar and host plants
The caterpillar is the showstopper: a plump larva covered in long pale-yellow to whitish hairs, with several longer black hair pencils (tufts) sticking out, two near the head and one near the rear. It feeds on a wide range of hardwoods including maple, oak, birch, elm, hickory, and willow. The hairs can cause an itchy rash or skin irritation in sensitive people, so admire it but do not pick it up. Larvae feed through summer and fall, then the species overwinters as a pupa in leaf litter or loose cocoon before adults emerge the next year.
How to see one at night
American Dagger Moths come well to artificial light. Set up a white sheet with a UV (blacklight) or mercury-vapor bulb on a warm, still, humid night, ideally with little moonlight, and check it through the evening. UV and short-wavelength light pull in far more moths than a plain white LED porch bulb. The leading explanation is that artificial light disrupts the way moths orient in flight, since they try to hold a bright source at a fixed angle the way they would the moon, rather than being lured toward a goal. New to this? Start with our beginner's guide to mothing and learn what makes a good night for moths.
This site does not identify a moth from your photo. It predicts which species are likely flying at your location and date from open records. For photo ID, try iNaturalist or Seek, BugGuide, the Moth Photographers Group, or BAMONA.