common door snail vs Eurasian Skylark

Clausilia bidentata compared with Alauda arvensis

Key Differences

• common door snail is Least Concern while Eurasian Skylark is Vulnerable.

Taxonomic Classification

Rank	common door snail	Eurasian Skylark
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Chordata (Chordates)
Class	Gastropoda (Gastropoda)	Aves (Birds)
Order	Stylommatophora (Stylommatophora)	Passeriformes (Songbirds)
Family	Clausiliidae	Alaudidae
Genus	Clausilia	Alauda
Species	Clausilia bidentata	Alauda arvensis

Evolutionary Relationship

common door snail and Eurasian Skylark share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

common door snail

LC — Least Concern

Eurasian Skylark

VU — Vulnerable

Physical Characteristics

Attribute	common door snail	Eurasian Skylark
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

common door snail

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Eurasian Skylark

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, tundra, and tropical and subtropical moist broadleaf forests spanning the Australasia and Oceanian realms.

Range

Widely distributed across Europe (5 countries), North America (Canada, United States), and Oceania and the Pacific (Australia, New Zealand). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

common door snail

<em>Clausilia bidentata</em>, the common door snail, is a terrestrial gastropod mollusk in the family Clausiliidae. This species is distributed across Belgium, Denmark, Norway, and Sweden, where it typically inhabits moist terrestrial environments including deciduous woodlands, rocky slopes, hedgerows, and the margins of freshwater habitats. The common door snail is recognized by its elongated, sinistral (left-handed) shell, which is a distinctive trait of the family Clausiliidae. The shell is typically brown to gray and reaches approximately 12–15 millimeters in length. <em>Clausilia bidentata</em> generally feeds on algae, lichens, fungi, and decaying plant material by rasping food with a radula. It often shelters under bark, stones, and leaf litter during dry or cold conditions. Like many clausiliids, it possesses a complex internal shell structure called a clausilium that closes the shell aperture to reduce desiccation. The species is assessed as Least Concern, reflecting stable populations across its European range. Detailed biological traits beyond those noted here are not extensively documented in the current scientific literature.

Eurasian Skylark

Celebrated across European literature and poetry for its complex, melodious song sung on the wing during spectacular display flights, Eurasian skylarks soar vertically hundreds of meters above open farmland, grassland, and heathland across Europe and Asia while producing an uninterrupted torrent of song lasting up to an hour. Males can produce over 700 distinct song phrases. Once enormously abundant across European farmland, skylark populations have declined over 70% since 1970 due to agricultural intensification.

Shared Countries

Both species can be found in 4 countries:

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