Bare-legged Swiftlet vs Clustered Stonewort

Aerodramus nuditarsus compared with Tolypella glomerata

Key Differences

Bare-legged Swiftlet is Least Concern while Clustered Stonewort is Vulnerable.

Taxonomic Classification

Rank	Bare-legged Swiftlet	Clustered Stonewort
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Chordata (Chordates)	Charophyta (Charophyta)
Class	Aves (Birds)	Charophyceae (Charophyceae)
Order	Apodiformes (Apodiformes)	Charales (Charales)
Family	Apodidae	Characeae
Genus	Aerodramus	Tolypella
Species	Aerodramus nuditarsus	Tolypella glomerata

Conservation Status

Bare-legged Swiftlet

LC — Least Concern

Clustered Stonewort

VU — Vulnerable

Physical Characteristics

Attribute	Bare-legged Swiftlet	Clustered Stonewort
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Bare-legged Swiftlet

Habitat

Typically found in various aerial, terrestrial, and aquatic environments.

Range

Found in Norway.

Clustered Stonewort

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

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

Bare-legged Swiftlet

The Bare-legged Swiftlet (Aerodramus nuditarsus) is a species in the genus Aerodramus. It is currently classified as Least Concern on the IUCN Red List. Typically found in various aerial, terrestrial, and aquatic environments.

Clustered Stonewort

Tolypella glomerata, the clustered stonewort, is a charophyte alga in the family Characeae, found in calcareous, nutrient-poor freshwater habitats including lakes, ponds, ditches, and slow-flowing water in northwestern and northern Europe. Charophytes are macroscopic green algae with a distinctive whorl-like arrangement of branches and a complex, plant-like structure that distinguishes them from other algae. T. glomerata is encrusted with calcium carbonate deposits (hence 'stonewort'), giving it a pale, grey-green appearance and rough texture. The species colonizes clear, low-nutrient water over fine sediment or gravel substrates where competition from vascular plants is reduced by nutrient limitation. It is listed as Vulnerable by the IUCN, reflecting significant declines driven by eutrophication (nutrient enrichment from agriculture and sewage), which promotes the growth of vascular plants and phytoplankton that shade out stoneworts. Drainage, water abstraction, and peat cutting also threaten its habitats. Charophyte diversity has declined substantially across lowland Europe and North America over the past century, with many species becoming locally extinct from sites they once colonized.