The nose of a wooden canoe slides through sunlit, glassy water, each stroke of the mokoro canoe rowing pole sending out a cascade of gleaming ripples. From above, Botswanas Okavango Delta is a maze of channels and lagoons winding through an ochre landscape, its waters eventually dissipating into the Kalahari Desert.
In the canoe, two men squint through their binoculars, searching for a Slaty Egret. Named for its slate-coloured feathers, it is considered a precious find among birdwatchers. But the reasons behind this expedition are far more urgent than simply catching a glimpse of a rare waterbird.
Data on bird distribution and whether the species is in decline, stable or increasing is critical, says Jeffrey Barbee, a renowned South Africa-based environmental journalist and photographer who has spent years advocating for stronger conservation of the Okavango Delta and the Slaty Egret through his non-profit foundation Alliance Earth. Why? Because the bird is considered one of the Deltas most important indicator species, meaning that its health reflects that of the overall ecosystem. Careful monitoring of this single species provides important clues about changes in the Deltas potential pollution, habitat changes and other conditions before wider deterioration of this vital ecosystem becomes more critical.
The growing impacts of climate change, which result in erratic rain patterns, along with pressures from agriculture, livestock and other human activities, disrupt the fragile balance of the Delta, affecting the habitat on which the Slaty Egret depends. Between 3,000 and 5,000 birds are estimated to remain most of them in the Delta putting the birds vulnerable classification on the International Union for Conservation of Nature (IUCN) Red List up for debate.
Should the bird be reclassified as endangered, there would be financial and land management implications across the Delta to protect the bird and, by proxy, the whole ecosystem. Such a decision is critically informed by the new surveys that scientists are conducting alongside communities, documented by Barbee.
In 2024, Botswanas Department of Wildlife and National Parks worked with BirdLife Botswana and other partners to establish the National Slaty Egret Working Group to help with this ongoing monitoring and conservation. But ultimately, the birds survival depends on the state of the Delta, and in a warming world, the Deltas overall health depends on that of the planet.
Local floods, global haven
Located in northwestern Botswana, the Okavango Delta, a UNESCO World Heritage Site, is profoundly unique. It is one of the worlds few major inland deltas whose life-giving waters either soak into the soft sands of the Kalahari desert or cycle directly back into the atmosphere, never reaching a sea or ocean.
The Deltas annual flood flows down between June and August from rains in Angolas highlands, creating a seasonal pulse that sets the rhythm of life for a multitude of animals and more than 400 species of birds from Africa and around the world. These birds, some from as far away as Europe and northern Asia, fly to the Delta each year, some using it as a stopover during a longer journey south, and some remaining for the duration of the northern winter. Migratory patterns of zebras, buffalo, elephants, wildebeest and various fish also freely move through the Delta from surrounding countries.
For the Slaty Egret, the floods arrival in August signals that its time to breed. This is a crucial time in its lifecycle, and one of the best periods for researchers and conservationists to monitor its behaviour and track its population trends.
Barbee and local experts paddle through the Okavango Delta on mokoro boats. Credit: Jeffrey Barbee ">
They like to nest on islands surrounded by water, or in other places where they wont be disturbed, says Jay Haikera, a local activist who founded the Etsha Bird Monitoring and Conservation Club in his local village. He and his club collaborate with the likes of Barbee and the Working Group, which last August conducted the largest-ever survey of the bird.
This years flood was greater than its been in some two decades, and the researchers were hopeful that it might have allowed the Slaty Egret to expand its breeding grounds into new areas. However, their latest expedition found that at last years main breeding site in the western Okavango Delta, no Slaty Egrets were nesting, and even sightings of the bird were very few. In another area of Delta in Jao Conservancy, two other former nesting sites, out of four in the area, were found to have disappeared: one from a fire, and the other from elephants using the area to cool off in the water after a summer heatwave, damaging the area.
The Slaty Egret is so sensitive to environmental disturbances and to system changes, says Monei Onalethata, a senior wildlife biologist with Botswanas Department of Wildlife and National Parks. Whatever happens in the ecosystem will necessarily reflect in the distribution and the presence of the bird.
Communities near and far
Because the current survey conducted by the Slaty Egret Working Group is still collecting this crucial data in the field, it is not yet possible to know what this years findings mean for the bird and its potential reclassification. But one positive outcome of its rise in importance is the increasing involvement and ongoing investment of local community groups in the birds future. It is so important to sensitize and work with local communities, says Barbee. Together with them, we can generate the type of information that shows how this [climate] crisis affects all our ecosystems.
Grassroots organizations like Haikeras Etsha Bird Monitoring and Conservation Club engage local communities and eco-tourism ventures to use mobile phones, mapping tools, and identification apps to collect and share their observations. Increasingly, youth are getting involved as well. The more we give feedback to the community, the more they will understand the importance of the Okavango Delta, explains Haikera.
Because migratory species do not recognize national borders, protecting them also requires strong regional and international cooperation to support these kinds of local and national initiatives. This is where international instruments such as the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) can really play a role, helping countries coordinate conservation efforts and mobilize resources.
The European Union is supporting migratory waterbird conservation in Africa mostly through development and biodiversity funding mechanisms, because they recognize that biodiversity loss and sustainable development are shared global concerns, says Sergey Dereliev, Acting Executive Secretary of AEWA, which is administered by the United Nations Environment Programme (UNEP). So even if the EU is far away from Botswana, they have recognized that helping preserve flagship species like the Slaty Egret actually has a global impact.
A last call
As part of this years monitoring effort, Barbee and Haikera recently journeyed deep into the Delta, to an area accessible primarily by helicopter.
As their boat glided through one of the narrow channels, the chirping of baby birds and guttural sound of calling parents made them pause and hold their breath. A nesting site was somewhere nearby. They poled toward a small island. There, concealed among leafy vegetation, three bluish eggs rested on a small platform of twigs. It was the first Slaty Egret nest Barbee and Haikera had seen this year.
The discovery offered some new hope after a long and often frustrating search. But determining whether it was simply a stroke of luck or a sign that years of painstaking monitoring and advocacy are beginning to pay off will require further research.
The production of this story was funded by the European Union. The European Union is a co-funder of the African-Eurasian Waterbird Agreement, an intergovernmental treaty administered by UNEP.
