Pied Crow Corvus albus numbers are increasing in many parts of South Africa. Recent work at the Fitz suggests that this increase is attributable to global warming and other anthropogenic factors, including the availability of nest sites on electrical infrastructure and increased food availability in urban areas and from road kills. In combination, these factors have seen the Pied Crow increase its abundance in some regions and expand its range locally. Our project investigates the expansion of this species, sometimes termed a ‘native invader’, and aims to understand what impacts these changes might have for biodiversity. Fitz research has focused on quantifying predation on tortoises and avian nests and suggested that crows may benefit from scavenging on the carcasses of road kills. Our current project builds on that research. In addition, we are examining the impact of Pied Crow expansion in response to powerlines on tortoise populations. We also work to gain a broad understanding of public perceptions of Pied Crows and their potential management.

As a generalist predator, Pied Crows may impose heavy predation pressure on a variety of species. Anecdotal evidence suggests that Pied Crows present a risk to threatened species such as endangered breeding waders and range-restricted tortoises. Because they may prey on species that are important for processes like seed dispersal, increases in crow numbers may influence ecosystems generally. Researchers and conservation organisations have begun drawing attention to the knowledge gap with regard to the ecological impacts of Pied Crows, emphasising the need for more research. Indeed, there is little information about the basic life history of Pied Crows, which is an essential component for understanding the potential impacts of a predator. Our work contributes to filling these knowledge gaps. 

Activities in 2025

  • MSc student Yusra Samsodien, funded by the Joan Wrench Kirstenbosch Scholarship (SANBI), completed her second year in the project. She is investigating Pied Crow range expansion in South Africa using SABAP2 data and exploring how anthropogenic factors influence the changes observed, with a special focus on the Western Cape fynbos. The results suggest that Pied Crows are increasing most rapidly in areas that are cooler, drier, and more modified by human activity. Yusra also examined the biodiversity impacts associated with increasing Pied Crow abundance on tortoise populations.
  • Yusra completed her field work along the Eskom powerline at Sere Windfarm near Lutzville in the Western Cape to investigate the impacts of linear infrastructure on Pied Crow and tortoise numbers. Yusra undertook four 10-day field trips to count tortoises and crows at different distances from the powerline. The results show that Pied Crow abundance was highest near the powerline, with Angulate Tortoise Chersina angulata abundance lowest in the same areas. This suggests that Pied Crow predation may lead to reduced Angulate Tortoise abundance near the powerline.

Highlights

  • Yusra presented a talk in the FitzPatrick’s Annual General Meeting seminar series titled ‘Pied Crows as a native invader in South Africa’.

Impact of the project

This research aims to improve our understanding of the drivers of increasing Pied Crow abundance in certain regions of South Africa and determine the associated implications for conservation, as well as what management actions might be most effective to deal with these concerns.

Key co-supporters
Joan Wrench Kirstenbosch Scholarship (SANBI); Endangered Wildlife Trust; BirdLife South Africa.

Research team 2025
Team leaders and collaborators:
A/Prof. Robert Thomson (FIAO, UCT)
A/Prof. Arjun Amar (FIAO, UCT)
Dr Colleen Seymour (SANBI / FIAO, UCT)
Lizel Tolken (EWT)

Student: 
Yusra Samsodien (MSc, UCT)