The House Crow is a versatile and abundant human commensal.  They are omnivorous and feed primarily on refuse supplemented by stolen food, crops, young domestic fowl, nest-raiding and predation of small animals, including terrestrial and marine invertebrates.  They need to drink regularly.

They forage around houses, parks, gardens, markets, among livestock and along the seashore. House Crows are typical Corvids in being intelligent and resourceful, but are unusual in being highly gregarious and commitment to life alongside human beings.  They can reach high population densities in urban areas, especially within their introduced range and large groups may gather at sources of food.  They frequently exhibit play behaviour, such as aerobatics, particularly as they head for their communal roosts at dusk, which may contain thousands of birds.  Though non-migratory, some altitudinal movements occur in colder regions.

They are noisy birds and can be very aggressive over food or when defending nest territory or young.  If alarmed their insistent “kaaa-kaaa-kaaa”s quickly summon support from nearby crows so the apparent threat is soon mobbed by a throng of shouting and wheeling crows, swooping and dive-bombing.  Birds of prey or other large birds wandering into House Crow territory are harassed mercilessly.

House Crows’ close association with man often leads to them achieving pest status as numbers build up, due to food theft, damage to crops and livestock, predation of native birds, noise, potential health risk, to the extent that control programmes have or are being attempted at many locations – usually with limited success.