Grevy’s zebra defy great odds to register increase in numbers

Tuesday July 3 2018

Grevys zebra, kenya wildlife service

Grevy’s zebra in the Lewa wildlife conservancy in northern Kenya. PHOTO | SUZI ESZTERHASI 

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If your home is steadily shrinking in size, your food supply dwindling and predators are out for your blood, then, increasing the size of your family may not be top on the list of your priorities.

This is the grim reality that faced the Grevy’s zebra over the past two years.

They faced a months-long drought that severely reduced pasture, competition from domestic livestock since 150,000 additional cattle roamed the rangeland, and then there were a slew of diseases such as anthrax, plus the scourge of poaching.

Grevy’s zebra are listed as endangered based on a steep population decline over the past 30 years.

In Kenya and Ethiopia, they are legally protected. Kenya holds more than 90 per cent of the global population in the wild.

In 2016, Kenya’s population of Grevy’s zebra was estimated at 2,350.

To establish how the Grevy’s had fared over the past two years, a census was taken at the beginning of this year.

On January 28 and 29, some 212 citizen photographers, riding in 143 vehicles participated in the second Great Grevy’s Rally covering 25,000Km2 and snapped more than 49,000 photographs, of which 23,000 were of Grevy’s zebras.

The census results were announced on June 23 at the Great Grevy’s Zebra Ball at the Fairmont Mount Kenya Safari Club in Nanyuki.

Nationally, the numbers were found to have increased from 2,350 (+/-93) to 2,812 (+/-163).

These increases are the result of enhanced efforts as more teams were assigned to areas where zebras are more sparsely distributed and they drove routes repeatedly.

Consequently, many individuals that were missed in the last rally were seen this time around. In effect, almost 300 new individuals were “found” in the 2018 rally.

For the most part, adult survival remained high. A large number of juveniles identified in the 2016 census survived to replace adults that had died off.

However, when the overall demographics — age and sex structure — of the population was examined, it was found that the dry spell affected the populations as the number of foals declined nationally from 11 per cent in 2016 to five per cent in 2018.

Action plan

At the gala, the Kenya Wildlife Service launched its 2017-2026 Recovery and Action Plan for the Grevy’s zebra.

The plan addresses threats like habitat degradation, competition for resources with wildlife, reduction of water sources, human-wildlife conflict, hunting, disease and predation.

Despite the environmental stressors, Grevy’s zebra populations have remained stable over the past two years.

Given that the drought ended with a deluge of heavy rainfall, rangelands in central and northern Kenya are now replete with grass.

Ordinarily, females that give birth and successfully rear their young to one year of age — the age of independence — skip one year, or even two, before conceiving again.

When females terminate pregnancies early or lose their young, however, they are likely to conceive during the next breeding season, especially if forage is plentiful.

It is highly likely that several foals will appear in 2019.