If you are currently in the coastal region of Kenya or have visited here in the past few months you may have noticed this black bird in the skies and streets, often bullying people and other birds and animals of their food. The House Crow Corvus splendens (formerly known as the Indian House Crow) has become a menace in this region, rapidly breeding and eventually taking over the coastal skies. But why the coast and nowhere else in the country?
The House Crow is not indigenous to the coast. As its earlier name suggests, it originates from India. It was introduced to East Africa first in Zanzibar in 1891 initially as a form of ‘pollution control’ but by 1917 was rated as a pest with a bounty awarded to any dead crow or crow egg brought in. It later spread to mainland Africa and up to Mombasa where it was first recorded in 1947. From there it spread up and down the coast becoming ‘common’ in Malindi in the late 1980s and is now in all the coastal towns and inland to Mariakani and beyond. It has become a serious pest in many places in Africa from East London in the south to Djibouti in the north. The hot and humid conditions of the Coastal areas are very ideal for the birds breeding, causing its numbers to multiply rapidly over a short period of time.
As with most exotic, introduced species, the House Crow has created a number of problems both in the natural ecosystems and for human communities. While it is true to some extent that they clean up the streets by eating the organic waste, better garbage control measures would greatly outweigh the importance of the bird to our ecosystem. Some of the problems the House Crow poses are;
- It predates on indigenous bird and animal species. It attacks other small birds’ nests eating the eggs, younglings and destroying the nest leading to the decline of indigenous bird species, small reptiles and mammals.
- House Crows harass and mob a wide variety of birds for no apparent reason other than to cause distress. Our A Rocha Kenya National Director, Colin Jackson, has personally seen a House Crow chase a Crab-plover off the beach in Watamu and continue to mob it for 2-300 metres across the water.
- House Crows cause direct and severe losses to agriculture and animal husbandry, taking eggs and chicks of free-range poultry, attacking new-born kids and calves, and feeding on germinating maize, sorghum and other crops
- Pollution & hygiene – a significant proportion of House Crow’s diet is human-generated rubbish which is often carried some distance from the rubbish dump to eat. This spreading of decomposing rubbish clearly increases the risk of spreading disease. Furthermore below the regular roosting and breeding sites considerable ‘guano’ can build up from the droppings – which if in a built-up area can also cause pollution and risk of disease for humans. Crows also make a lot of noise – which for some might be significant ‘noise pollution’. House Crows have also been shown to be carriers of up to eight human parasites.
- Tourists, hotel owners and street vendors are also afflicted by the birds. Despite having a taste for rubbish, the crow also has a taste for coastal delicacies. They have been reported stealing food from tourists’ plates and vendors’ food products. The smart bird is capable of this by employing patience and abundance in numbers to attack unsuspecting people.
“Local residents who own chicken also suffer. The crows use teamwork and cunningness to attack and steal chicks. If the mother hen is aggressive, they will feign friendship, playing with the chicks to gain trust at first, then killing them when they have the opportunity. One crow could also distract the mother-hen while the other crows swoop in and steal the unprotected chicks,” Kirao, A Rocha Kenya avian researcher, explains.
A Rocha Kenya’s expertise in birding is a silver lining in this looming dark cloud. We have been conducting crow counts in order to study their movement and breeding habits. Since the birds are social creatures, they like to roost in great numbers in specific trees around the towns they feed on. They leave this location in the morning to forage and come back in the evening to roost together. By studying these patterns, we are able to know the best way to control the bird population and where to target them.
Controlling their numbers is no easy task. Some people have successfully used traps to capture them but it is a slow process with a very small impact on the large numbers of these birds. A Rocha Kenya has previously been approached to control the bird population and was successful in bringing the numbers relatively low to restore the balance of the ecosystem. We are working with African Fund for Endangered Species (AFEW) and the Kenya Wildlife Service (KWS) towards having a clear coastal sky soon, and hope we can permanently control this avian plague.