Common Merganser vs Common Roller

Mergus merganser compared with Ancylis badiana

Taxonomic Classification

Rank	Common Merganser	Common Roller
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Chordata (Chordates)	Arthropoda (Arthropods)
Class	Aves (Birds)	Insecta (Insects)
Order	Anseriformes (Anseriformes)	Lepidoptera (Butterflies & Moths)
Family	Anatidae	Tortricidae
Genus	Mergus	Ancylis
Species	Mergus merganser	Ancylis badiana

Evolutionary Relationship

Common Merganser and Common Roller share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Common Merganser

LC — Least Concern

Common Roller

LC — Least Concern

Physical Characteristics

Attribute	Common Merganser	Common Roller
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Merganser

Habitat

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

Range

Found across Europe (5 countries) and North America (United States).

Common Roller

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Common Merganser

<em>Mergus merganser</em>, the common merganser or goosander, is a large diving duck in the family Anatidae, broadly distributed across Europe and North America. It is classified as Least Concern on the IUCN Red List. This species is capable of aerial, terrestrial, and aquatic locomotion, but is most specialized for underwater pursuit of prey. The common merganser is typically piscivorous, diving in clear, fast-flowing rivers and lakes to catch fish using its serrated bill, which provides a firm grip on slippery prey. Males display striking breeding plumage with a dark green head, white body, and red bill, while females are grey with a rusty-brown head and crested nape. The species nests in tree cavities, cliff ledges, and artificial nest boxes near freshwater habitats. It requires clean, well-oxygenated rivers and lakes for foraging, making it sensitive to water quality degradation and overfishing of prey species. Common mergansers are migratory in northern parts of their range, moving to coastal and ice-free inland waters during winter months.

Common Roller

<em>Ancylis badiana</em>, the common roller, is a small moth in the family Tortricidae, order Lepidoptera. It is distributed across northwestern Europe, with documented records from Belgium, Denmark, Norway, and Sweden, typically inhabiting woodland margins, hedgerows, scrubland, and areas where its larval host plants are abundant. The species is assessed as Least Concern on the IUCN Red List. Tortricid moths in the genus Ancylis are commonly known as "rollers" or "leafrollers" because their larvae typically roll or fold leaves of host plants to create sheltered feeding structures. <em>Ancylis badiana</em> larvae feed on the foliage of various herbaceous plants, particularly species in the pea family (Fabaceae). Adults are small moths with intricately patterned wings that provide camouflage against bark and plant material. Adult moths are primarily nocturnal and are attracted to light, while larvae are cryptic within their leaf shelters. Biological traits such as lifespan, body measurements, and detailed diet host range remain poorly documented beyond general family-level characteristics. The species typically completes one to two generations per year in temperate European climates, overwintering as pupae. It is considered a minor component of invertebrate biodiversity in European lowland habitats.

Shared Countries

Both species can be found in 4 countries:

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