Page 27 - State of Biodiversity 2019-2020

The surveillance of the distribution of House Crows within EM, serves as a precursor to actual control. This step of controlling the species is aimed at understanding where these birds roost, forage, breed and which places they frequent. Such information is then fed into the actual control, which is undertaken by a registered service provider. Several options are available for dealing with these birds, for instance, they can be trapped, baited and/or euthanised on the spot, while eggs in nests can be compromised to ensure no hatchlings results from that breeding episode.
While interventions do have pros and cons, some prove better than others.Trapping, for one, is tedious in that traps must always be checked, moved around and refreshed. Once birds are caught, the next part is not always easy! Baiting, on the other hand, is hard to measure until such time as the birds are no longer found. Once a bird takes the bait, there is no control of where it will end up unless a highly potent substance is applied. Furthermore, there is no guarantee that a House Crow will take that bait. So, finding a potent, species-specific chemical is always a challenge. Shooting, by a qualified, disciplined, registered and experienced service provider, proves a better option, with a good indication of success. Shooting minimises collateral damage and the number of euthanised birds is always known, with a very small margin of error. During 2018/2019, a total of 57 birds were euthanised within eThekwini Municipality.
Collaboration and/or complementary projects should be implemented in neighbouring municipalities, including King Cetshwayo (Richards Bay). Otherwise, efforts in one municipality will be fruitless until there is a coordinated, sustained approach. In other countries such as Zanzibar,Tanzania and Uganda, etc., these birds have established themselves and occur in thousands.While the species has established in more than 20 countries, outside of their native range (Asia, native to countries such as Nepal, Bangladesh, India, Pakistan and Sri Lanka), these birds spread diseases such as paramyxoviruses, Cryptococcus neoformans, which can cause cryptococcosis in humans. They are also a vector for pathogens that cause cholera, typhoid, dysentery and salmonella poisoning. Big populations of these birds are also a threat to primary production industries, causing severe damage to agricultural and horticultural crops. They occasionally destroy vegetable gardens in
informal settlements. They create a nuisance for people through scattering rubbish, causing noise and damaging urban and electrical infrastructure. They have been reported to regularly mob humans, especially children and pets.
House Crow are considered a major pest of the environment, preying on chicks and eggs of indigenous birds and destroying their nests as well as eating small indigenous animals like frogs.
Given the impacts of the species on both native biodiversity and on the economy, control efforts in curbing the establishment of the species should never be done on an ad hoc basis. A provincial, if not national, strategy on the management of the species should be implemented. Resources should be made available to make sure that projects aimed at controlling the species are maintained within and between financial years. Lessons learnt should be documented and used to inform future management interventions.
House Crow sightings can be reported to: Mmatjie.Mashao@durban.gov.za
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