India, Oct. 8 -- The behavioural shifts of the Slaty Egret (Egretta vinaceigula), a small, shy water bird mainly found in Botswana's Okavango Delta, are an important instance of changes in natural ecosystems, United Nations Environment Programme (UNEP) officials said recently.

Only around 3,000 Slaty Egrets are estimated to remain in the Delta, its principal stronghold.

"The Slaty Egret is so sensitive to environmental disturbances and to system changes," Monei Onalethata, a senior wildlife biologist with Botswana's Department of Wildlife and National Parks, said in a UNEP statement issued in the backdrop of World Migratory Bird Day themed around "Every Bird Counts - Your Observations Matter!",

"Whatever happens in the ecosystem will n...