Black-billed Flycatcher vs Concentric Boulder Lichen

Aphanotriccus audax compared with Porpidia crustulata

Key Differences

Black-billed Flycatcher is Near Threatened while Concentric Boulder Lichen is Vulnerable.

Taxonomic Classification

Rank	Black-billed Flycatcher	Concentric Boulder Lichen
Kingdom	Animalia (Animals)	Fungi (Fungi)
Phylum	Chordata (Chordates)	Ascomycota (Sac Fungi)
Class	Aves (Birds)	Lecanoromycetes (Lecanoromycetes)
Order	Passeriformes (Songbirds)	Lecideales (Lecideales)
Family	Tyrannidae	Lecideaceae
Genus	Aphanotriccus	Porpidia
Species	Aphanotriccus audax	Porpidia crustulata

Conservation Status

Black-billed Flycatcher

NT — Near Threatened

Concentric Boulder Lichen

VU — Vulnerable

Physical Characteristics

Attribute	Black-billed Flycatcher	Concentric Boulder Lichen
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Black-billed Flycatcher

Habitat

Inhabits tropical and subtropical moist broadleaf forests and tropical and subtropical dry broadleaf forests within the Neotropic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Distributed across Colombia, Norway, and Panama. Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

Concentric Boulder Lichen

Habitat

Native to Europe and North America, inhabiting ecosystems characteristic of the region.

Range

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

Black-billed Flycatcher

The Black-billed Flycatcher (Aphanotriccus audax) is a species in the genus Aphanotriccus. It is currently classified as Near Threatened on the IUCN Red List. Inhabits tropical and subtropical moist broadleaf forests and tropical and subtropical dry broadleaf forests within the Neotropic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Concentric Boulder Lichen

<em>Porpidia crustulata</em>, commonly known as the Concentric Boulder Lichen, is a crustose lichen in the family Porpidiaceae formed through a symbiotic relationship between a fungal partner (mycobiont) and photosynthetic green algae (photobiont). Like all crustose lichens, it grows tightly appressed to its substrate—typically siliceous or acidic rock surfaces including boulders, cliff faces, and pebbles in open, well-lit habitats—forming thin, grayish to pale thalli marked by scattered black apothecia (reproductive discs). <em>Porpidia crustulata</em> derives nutrition entirely through photosynthesis conducted by its algal partner, requiring no external organic food source. The species has been documented in Denmark, Norway, Portugal, Sweden, and the United States, suggesting a broad boreal to temperate distribution across the Northern Hemisphere. It is currently classified as Vulnerable by the IUCN, indicating significant conservation concern, likely linked to threats including air pollution, acidification, quarrying of rocky habitats, and changes in land use that reduce the availability of suitable substrates. Crustose lichens are typically slow-growing, long-lived organisms with limited capacity for rapid range shifts in response to environmental change. Biological traits such as individual lifespan, growth rates, and reproductive output remain poorly documented at the population level.