The Great Grevy’s Rally (GGR) was conceived by members of Kenya's Grevy's Zebra Technical Committee as a means to census the endangered population of Grevy's zebra. A census is a methodical count of a species' population.  Grevy's Zebra Trust, Mpala Research Centre, Lewa Wildlife Conservancy, Marwell Wildlife and Northern Rangelands Trust's community conservancies constantly monitor Grevy's zebra populations and demographics across northern Kenya. However in order to accurately estimate the population, we need to conduct a thorough ground census.

Using sophisticated stripe recognition software to analyze the number of sighted and re-sighted individuals over two consecutive days, the population size of Grevy’s zebras in northern Kenya will be estimated.  This methodology will also provide insights on the age and sex structure of the Grevy’s zebra population in each area to assess whether or not the overall Grevy’s zebra population is stable, growing or decreasing. The population estimate and distribution determined by the GGR will inform future conservation and management initiatives.

What is the Great Grevy's Rally?

The GGR is a national census of Grevy's zebra. The rally brings together scientists, landowners, conservancies and members of the public in driving through designated areas and photographing  the right side of each individual Grevy's zebra observed with a provided GPS enabled digital camera. Each Grevy's zebra has a unique stripe pattern, which allows us to identify each individual. The photographs will then be processed by the Image Based Ecological Information System (IBEIS), which will identify the individual and its age and sex, and will record the observational time and location. The IBEIS results will estimate the size of the Grevy's zebra population throughout Kenya.  

How does this help Grevy’s zebra?

In addition to providing an updated population estimate, each photograph will contribute to the current population age and sex structures. The age and sex structure of a population indicates its potential to grow. For example, if the total number of juveniles and foals account for 25% of the total population, then the population is on the rise. As for sex structure, if there are three females for every one male, then there is high potential reproduction and overall population growth. The population's distribution and age and sex structures will indicate areas of high and low growth potential. With this information, Grevy's zebra conservation partners will investigate what factors are contributing to these results.