Perennial floods, tiger predation and human intervention in Kaziranga National Park have taken off their toll on the rare species of swamp deer, whose population in the recent years has shockingly declined.Alarmed environmentalists have called for special conservation projects to save the inhabitants of the park spread over eight blocks.The highest number of swamp deer, 756, was recorded in 1984 while in 1998, it has come down to 526, according to a census carried out by the park authorities recently.