The percentage of water birds at the Kaziranga National Park and Tiger Reserve (KNP & TR) in Assam declined by 28.61 per cent in one year, officials said on Tuesday.

KNP & TR Director Karmashree P. Sivakumar told IANS that the decrease in the number of water birds was due to accumulation of water hyacinth in Rowmari wetland under the Laokhowa wildlife sanctuary.