Invasive of the month: House Crow

The House Crow (Corvus splendens (Vieillot, 1816) is an aggressive and often invasive bird that originates from the Indian Sub-Content and parts of South-East Asia. It has been introduced to many tropical and sub-tropical countries (and there is even a small colony in The Netherlands) where it has become an urban and domestic pest, stealing human food, polluting human habitation, spreading human diseases, delighting in garbage and living in noisy colonies.

 Flocks of introduced birds prey upon domestic chickens and other poultry and their eggs as well as upon native birds, reptiles and small mammals.  They have spread along the eastern coast of Africa to its extremes in northern Egypt and in South Africa – occupying most coastal towns and moving hundreds of kilometers inland.  House cows are now present in most countries of the Arabian Peninsular and in some warmer localities of the Mediterranean.  They have also spread eastwards into East Asia and are occasionally found in Western Australia where (so far) they have been eradicated before being able to establish their presence.

The habits of these crows when invading new territory are extremely detrimental to native biodiversity in a range of invertebrate and vertebrate groups – but especially in passerine birds.  They also have serious impacts on infrastructure such as the insulation of electrical wiring and wireless installations and can seriously affect tourism(and urban living) because of their noise and nuisance value.  Eradication of small groups is possible through trapping, hunting and chemical means, but control of large infestations is almost impossible as the crows learn quickly how to avoid human attempts to catch or kill them and they even attack people trying to manage their flocks.  This is an invasive species for which it is imperative to act fast upon first arrival of these birds before they breed and spread – a classic case for the need for rapid response and direct action.  There are many situations where this action has not been taken – to the detriment of urban environments, human habitation and livelihoods as well as native biodiversity.

• http://www.isg.org/database/ enter “Corvus splendens”
• http://www.housecrow.com
• http://www.agric.wa.gov.au/content/pw/vp/bird/housecrow_nht.pdf

Reference: Meier G.G. and Ryall C.  The House Crow (Corvus splendens), an invasion without limits. Aliens (The Newsletter of the Invasive Species Specialist Group of IUCN) 26: 21-22.