Habitat – The House Crow is typically a tropical species, but even in its native range can be found living at high altitudes such as the slopes of the Himalayas, where the climate is more temperate, and this ability to withstand cooler climates is confirmed by the presence of the growing colony in the Netherlands.
They inhabit any area where humans live and reach highest numbers in dense human settlements where there is plentiful access to garbage, crops and livestock; whereas they are absent where humans are few or absent, for example, deserts and dense forests.
Feeding strategies – House Crows are versatile and abundant commensals of man. They are omnivorous and feed primarily on refuse supplemented by stolen food, carrion, crops, young domestic fowl, nest-raiding and predation of small animals, including terrestrial and marine invertebrates. Like most other species of crow, House Crows have the intelligence to use a very wide variety of additional foraging strategies, such as searching for insects, picking ticks and opening up wounds on livestock, and picking discarded fish from the water surface.
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 in their 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 need to drink regularly.
Behaviour – 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 perceived threat is soon mobbed by a throng of shouting and wheeling crows, swooping, dive-bombing and defaecating. Birds of prey and other large birds wandering into House Crow territory are harassed mercilessly. Humans are sometimes attacked, usually during the breeding season when they inadvertently get close to a chick that has fallen from the next, for example.
They frequently exhibit play behaviour, such as aerobatics, particularly as they head for their communal roosts at dusk, which may contain thousands of birds. These roosts are sometimes shared with other bird species including mynas, parakeets and egrets. Though non-migratory, some altitudinal movements occur in colder regions in the north of their native range.
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, noise, potential health risk through fouling of human living space, and they are serious predators of native birds, to the extent that control programmes have or are being attempted at many locations – usually with limited success. Introduced House Crow populations have, however, been successfully eradicated in some areas, namely, Durban, SA, the Seychelles and the Yemeni island of Socotra.