The common raven is a large all-black passerine bird. It is the most widely distributed of all corvids, found across the Northern Hemisphere. It is a raven known by many names at the subspecies level; there are at least eight subspecies with little variation in appearance, although recent research has demonstrated significant genetic differences among populations from various regions. It is one of the two largest corvids, alongside the thick-billed raven, and is possibly the heaviest passerine bird; at maturity, the common raven averages 63 centimetres in length and 1.47 kilograms in mass. Although their typical lifespan is considerably shorter, common ravens can live more than 23 years in the wild. Young birds may travel in flocks but later mate for life, with each mated pair defending a territory.
Common raven
In sunlight, the plumage can display a blue or purple sheen which is a result of iridescence.
Two juveniles in Iceland
Common Ravens panting to cool down in 110 °F (43 °C) heat in Palm Desert, California
A passerine is any bird of the order Passeriformes which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their toes, which facilitates perching.
Passerine
Pterylosis or the feather tracts in a typical passerine
Male superb lyrebird (Menura novaehollandiae): This unique songbird shows strong sexual dimorphism, with a peculiarly apomorphic display of plumage in males.
Wieslochia fossil