Hydriomena nubilofasciata

Distinguished from other winter-flying geometrids by its association with oak habitat and flight period in late January to February. The specific epithet 'nubilofasciata' refers to the cloudy-banded wing pattern. Separation from congeneric species requires examination of genitalia or detailed wing pattern analysis.

Adults have a wingspan of 24–30 mm. Wings are grayish with darker transverse lines and a somewhat mottled appearance. The species lacks bright coloration, consistent with its winter-active habit. Resting posture typical of Geometridae, with wings held flat or slightly overlapping.

Associated with oak trees (Quercus spp.). Adults are found in woodland and forested areas where oaks are present. Specific larval host plant microhabitat not documented in available sources.

Recorded from North America, with confirmed presence in the northeastern United States including Vermont. Distribution likely broader within eastern North American oak forests, but precise range boundaries are not well documented.

Adults are active in late January and February. This represents an unusually early flight period for a temperate North American moth, with activity occurring during winter months.

Adults fly during winter months when temperatures permit, an uncommon trait among North American Lepidoptera. Activity is centered around oak trees, suggesting either adult feeding or oviposition behavior associated with this host.

• Other Hydriomena speciesMany congeners occur in similar habitats but differ in flight period; most Hydriomena fly in spring or summer rather than mid-winter
• Operophtera brumata (winter moth)Also a winter-flying geometrid, but occurs later (November–December in North America) and shows sexual dimorphism in wing reduction

• winter active
• oak associated
• geometrid moth
• early season

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life