clouded magpie vs Common Oak Fern

Abraxas sylvata compared with Gymnocarpium dryopteris

Key Differences

• clouded magpie is Vulnerable while Common Oak Fern is Critically Endangered.

Taxonomic Classification

Rank	clouded magpie	Common Oak Fern
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Arthropoda (Arthropods)	Tracheophyta
Class	Insecta (Insects)	Polypodiopsida (Polypodiopsida)
Order	Lepidoptera (Butterflies & Moths)	Polypodiales (Polypodiales)
Family	Geometridae	Cystopteridaceae
Genus	Abraxas	Gymnocarpium
Species	Abraxas sylvata	Gymnocarpium dryopteris

Conservation Status

clouded magpie

VU — Vulnerable

Common Oak Fern

CR — Critically Endangered

Physical Characteristics

Attribute	clouded magpie	Common Oak Fern
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

clouded magpie

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Oak Fern

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 4 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found across Europe (6 countries) and North America (Canada, United States). Currently classified as Critically Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

clouded magpie

The clouded magpie (Abraxas sylvata) is a geometrid moth in the family Geometridae found across temperate Europe, extending eastward through Russia to Japan. The adult wingspan measures approximately 32–42 mm, with white wings bearing a distinctive pattern of yellow-orange and dark grey to black spots and patches arranged in rows across the forewing and hindwing, creating a striking patterned appearance resembling the magpie coloring of the related magpie moth Abraxas grossulariata, but with a more yellowish, muted tone and less black — hence 'clouded.' Adults fly in one generation from June to July, resting on leaf surfaces and attending woodland flowers for nectar. The larvae feed on wych elm (Ulmus glabra) and occasionally other Ulmus species in mature deciduous woodland and woodland edges. The clouded magpie has become less common in parts of its European range due to the widespread loss of mature elms from Dutch elm disease, which devastated European elm populations from the 1970s onward. Conservation of this species requires the protection of surviving mature elm trees and management of regrowth elms in woodland ecosystems.

Common Oak Fern

<em>Gymnocarpium dryopteris</em>, the common oak fern, is a delicate terrestrial fern in the family Cystopteridaceae (or Woodsiaceae, depending on classification). Despite its common name, the species is not specifically associated with oak trees; rather, it typically grows in cool, moist, shaded environments including boreal and mixed forests, rocky woodland slopes, stream banks, and shaded cliff faces. <em>Gymnocarpium dryopteris</em> spreads by rhizomes and forms low, spreading colonies with characteristic triangular, three-pinnate fronds that emerge from a slender creeping rootstock. Its geographic range spans Europe and North America, with populations in cool temperate and boreal zones. The species is currently assessed as Critically Endangered in certain regional assessments, suggesting that particular populations face severe decline, likely due to habitat loss, forest fragmentation, and altered hydrology, even if the species retains a broader global range. Biological traits such as lifespan, body size, and diet remain poorly documented at a standardized population level. <em>Gymnocarpium dryopteris</em> is a characteristic indicator of undisturbed cool woodland habitats and is valued for both its ecological role in forest understoreys and its aesthetic appeal.

Shared Countries

Both species can be found in 4 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden