Effect of rainfall on Blue Cranes in the Eastern Karoo

Example of a project conducted by the Population Ecology Group at SANBI.

Photo: Mark Anderson

This project was undertaken in collaboration with Mark Anderson of BirdLife South Africa. Blue Cranes were colour ringed and resighted.

Some of the ringed birds were found dead. We estimated survival using statistical models that account for the fact that not every surviving crane was resighted and only a fraction of dead cranes are found.

We used the number of young cranes seen during road counts as a measure of reproduction. Survival and reproduction were related to rainfall during different times of the year. We used matrix population models to gauge the effect of rainfall on Blue Crane populations. This gives us a tool to predict the fate of Blue Cranes in the eastern Karoo should rainfall change in the future.