Egret proves elusive in world?s largest Ramsar site
Breeding Sites not found?A survey team from BirdLife Botswana and the Botswana Department of Wildlife and National Parks recently completed a one-year survey of the 55,000 km2 Okavango Delta, the world’s largest Ramsar site and principal home of the Slaty Egret Egretta vinaceigula.
Valuable data on the ecology of this Vulnerable species were collected, but one question remains unanswered: where are Slaty Egrets currently breeding? The species usually nests in dense reedbeds and water fig islands, but the major historical breeding sites have been destroyed by hydrological changes and fire, and no new sites were discovered in 2005. Continuing survey work hopes to answer this question.By contrast, Slaty Egrets feed in shallow seasonal floodplains with short, emergent vegetation, a habitat that is widespread throughout the Delta and has increased through fire and high grazing pressure. Birds spend most of the day foraging for small fish, frogs and aquatic invertebrates which they locate by sight, but despite the abundance of prey, they appear to have a low feeding success.
The Okavango Delta wetland area is currently just over half its maximum size of 20,000 km2, possibly because of long-term climate fluctuations. This drying out has led to several factors that threaten the egret, notably increased accessibility and disturbance to reedbeds by cutters and tourists, loss of some feeding areas, destruction of habitat by fire and the increased use of reedbeds by large mammals, especially elephants.
Information gathered from the recent surveys will be incorporated into a Slaty Egret Action Plan that will help BirdLife Botswana, the Department of Wildlife and National Parks and other stakeholders to ensure the Okavango Delta continues to provide a safe haven for Slaty Egrets.
4th July 2014