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Bank Cormorant Conservation Research

Bank Cormorant family. Image: Richard Sherley
A bank cormorant nest at Robben Island.
Image © Richard B. Sherley.

The Bank Cormorant colony on Robben Island, being monitored by remote camera. Image: Les Underhill, ADU
The bank cormorant colony on Robben Island, 
being monitored by remote camera. 
Image © Les Underhill, ADU.
Seabirds, because they feed near to the top of food webs, are indicator species for the health of marine ecosystems. The populations of several seabird species in the Benguela upwelling ecosystem have undergone large decreases in the last 50 to 100 years, linked in many cases to losses of their prey base either through large-scale changes in the ecosystem or the impacts of man.

The bank cormorant Phalacrocorax neglectus 
is a poorly studied, endangered seabird, endemic to South Africa and Namibia. The population decreased by 66% over the last 40 years to around 3 000 pairs. Our project focusses on conservation research for this species. The mechanisms driving the population trends have not been fully explored or elucidated. Human disturbance, displacement by seals, and changes in prey availability have been implicated in the past, while a recent study has indicated roles for climate variability and food quality that have hitherto been unexplored. Little routine monitoring or directed research has been carried out on bank cormorants in South Africa since the 1970's. Starting in 2012, we initiated a three-year study to (1) elucidate the role that changes in prey availability might have played in the past declines in southern Africa and (2) explore the hypothesis that broad-scale changes in climate and the southern Benguela Upwelling System could have contributed to the past declines.

At present, monitoring is primarily based on visual observation. Breeding success, chick-provisioning behaviour and thermoregulatory behaviour are currently being assessed at three colonies in the Western Cape (Robben Island, Jutten Island, Stony Point). Over the coming field seasons, we aim to extend the monitoring to include the deployment of remote-sensing technology (GPS loggers) to study foraging behaviour and the ringing of chicks to allow for survival analysis. Through collaborations with colleagues in Namibia data will be gathered and analysed for the same four variables at Mercury Island, Namibia. This is a site for which some baseline data on bank cormorants exists.

Beyond the time-frame of the initial project, we hope to develop an annual monitoring programme, using a combination of methods above, which will improve our understanding of the factors driving the population dynamics of the species in South Africa. In doing so, we will have initiated long-term datasets to contribute to conservation decision making and ecosystem modelling studies. The ultimate goal is to propose a collaborative management plan for the conservation of this endangered species.

This project is a carried out in collaboration with the Percy FitzPatrick Institute of African Ornithology and funded by a SEAChange grant from the National Research Foundation. Two research students who worked on the project graduated in 2014.