Crows are birds belonging to the order Passeriformes. There are about 40 species, distributed mostly throughout Europe, Asia , North America and North Africa. The best known species are the common crow and the raven. Ravens are particularly large birds which can reach 69 cm in height with a weight of 1.5 kg. Almost all crows have black legs , beaks and plumage, but some varieties, such as the hooded crow, have light patches in some areas of their body. Crows are omnivores: their diet consists of fruits, seeds, fish and even small rodents. They kill their prey with the slightly hooked tips of their beaks.
But they also feed on carcasses and rubbish, which is why crows are often seen around rubbish dumps scavenging for food .
Considered among the most intelligent birds , they are able to adapt to different types of habitats, including human settlements. Many species have a strong herd instinct that drives them to live in flocks, in order to defend themselves from predators such as birds of prey. Several species, including the raven, are monogamous. The mating season begins in late winter when males perform demonstrations of aerobatic flying and offer food to females . The male and female build a nest together, weaving it from twigs and blades of grass. The female lays an average of 3 to 7 eggs, which are incubated for about 3 weeks . The offspring take their first flight from the nest after 5 or 6 weeks. The bird’s dark color and hoarse croak has led to the raven to be associated with negative values or to be perceived as a messanger of doom and death. This disturbing imagery often associated with ravens appears in the poem “The Raven” by Edgar Allan Poe. In northern mythology, however, ravens are faithful companions to the god Odin. Two of these birds, Hugin and Munin , represent "thought" and "memory"; they fly across the world then return to Odin’s shoulder to report back what they’ve witnessed .