How invasive species became Kenya's million-bird menace

It has been nearly eight decades since the house crow was first sighted in Kenya. By June 2024, its population in the country was estimated at over one million. Among the factors contributing to this population boom, the abundance of open garbage is significant.

“The crow loves garbage,” says Hamisi Mwandaro, the municipal manager of Ukunda in Kwale County.

“This is both good and bad. Good, because it helps remove harmful materials from the environment—materials that could cause diseases. Bad, because the crow is an invasive species that harms biodiversity and is destructive to poultry,” he adds.

Dr Colin Jackson, an ornithologist at A Rocha Kenya explains that the crow’s abundance along the coast is, in part, an indictment of the state of garbage management in coastal towns. “If city councils managed rubbish disposal properly, it would deny the bird a steady supply of food,” he says.

However, with a current house crow population exceeding a million, Dr Jackson argues that efficient garbage management alone will not be sufficient to control the species.

The crow family, known scientifically as Corvidae or Corvids, includes six species in Kenya.

“We have three species of the ravens, the rook, the house crow, and the pied crow,” says Paul Gicheru, a wildlife ecologist and Species and Sites Programmes Manager at the conservation non-profit Nature Kenya.

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The house crow and the pied crow closely resemble each other, even making similar sounds. However, there are notable differences.

“The house crow appears blackish from a distance, but has a grey hue starting from behind its neck and extending around its head, chest, and belly,” says Dr Jackson.

“The pied crow—the ‘good’ crow—has white feathers on its chest, belly, and neck. It is native to Kenya and Africa and does not have the destructive habits of the house crow,” he adds.

In fact, the pied crow has suffered due to the house crow. Historically, the coastal region had more pied crows than house crows. However, the house crow has preyed on the pied crow’s eggs and chicks, terrorising it and forcing it to move away from the coast, Dr Jackson notes.

Scientifically, the house crow is identified as Corvus splendens, while the pied crow is known as Corvus albus. Locally, in Watamu, the two species are also referred to by different names: the pied crow is called Kurabu, while the house crow is known as Kunguru.