Indian crows have wings clipped
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Cape Town - Big Brother is on to aliens of a feathered kind and can now track their movements more accurately thanks to co-operation from an unexpected source.
The Indian house crow is the cocky, smaller cousin of our indigenous pied crow and Cape crow.
Now the Indian bird will have its wings clipped by the city’s Invasive Species Unit after the unit negotiated a partnership with the National Ports Authority that allows it access to Table Bay Harbour.
And that is because it has been established that the Indian house crow prefers sea travel to air travel.
“House crows are ‘hitchhikers’, travelling by ship from their native range of India, Pakistan and Burma to countries where they do not naturally occur, such as Tanzania, Mozambique and South Africa,” said Johan van der Merwe, mayoral committee member for the environment.
“We have a better chance of winning the battle if we are able to prevent them from entering the country. The ability to monitor the birds from the harbour affords the Indian house crow team a better chance of detecting house crows.
“Over the past six years the city, in partnership with the national Department of Environmental Affairs’ Natural Resources Management Programme, has worked tirelessly to control the Indian house crow population and to prevent the establishment of new roosts.”
Since the start of the Indian house crow control programme in December 2009, the population has been reduced to fewer than 500 birds. They are regarded as one of the world’s 100 most damaging invasive species, first arriving in SA in the early 1980s.
Indian house crows are known to be aggressive, opportunistic feeders. They have a negative impact on indigenous bird and animal populations, agricultural crops and domestic poultry. They also pose a health hazard to humans as they are carriers of enteric (intestinal) diseases that are transmitted through their beaks or claws.
Louise Stafford, manager of the Invasive Species Unit, said: “The impact on indigenous crows may be negligible, but is more significant on other smaller birds such as Cape white eye and sugarbirds.
“However, studies were not conducted to quantify the impacts, so it will be difficult to give numbers. What we know is that house crows prey on fledglings of indigenous birds and destroy their nests.”
The species is listed in the National Environmental Management: Biodiversity Management Act 10 of 2004 regulations as category 1a, which is a species requiring immediate steps for eradication.
Van der Merwe said he believed that, thanks to co-operation with bodies such as the ports authority, a 2017 target date for complete control of the house crow was realistic.
Invasive Indian house crows should not be confused with indigenous Cape crows or pied crows, the latter of which are common in Cape Town suburbs. Pied crows are the only crows with a white breast, while the Cape crow is black and is larger than the invasive Indian house crow.
All sightings of house crows, together with GPS coordinates, can be reported to www.ispot.org.za.