A Nova Scotia biologist says he and others in the scientific community are perplexed that the federal government has not declared bats an endangered species.

Mark Elderkin, the endangered species biologist for the wildlife division of the Nova Scotia Department of Natural Resources, said researchers believe bats all over eastern North America are facing a real possibility of extinction.

An estimated 90 per cent of little brown bats, northern long-eared bats and tri-coloured bats in Nova Scotia could be lost this year.

"Those three species have had enormous, unprecedented decline," said Elderkin, speaking on behalf of a regional group of scientists.

White-nose syndrome causes the bats to wake early from hibernation. They can die from dehydration, starvation and exposure.

On Prince Edward Island, wildlife pathologist Scott McBurney has received reports of bats behaving oddly, such as flying during the day looking for insects.

"It's something that I call a dead bat flying because they are exhibiting that behaviour out of desperation," he said.

"This past winter has been the most significant mortality that we have seen since this disease has emerged in our region."

Elderkin is pushing for the federal government to give bats endangered species status, which would lead to better research as the killer disease moves towards bats in the west and to the north.

"Maybe the best we are going to be is documentarians of one of the most horrific events in terms of mammalian ecological history," he said.

Elderkin said their approval appears to be stalled at the Environment Canada offices.

"Politicians and even the public have some attitude that these are just bats," he said.

An assistant to Peter Kent, the federal Minister of the Environment, told CBC News she is attempting to track down information on the status of the request from Elderkin.

But McBurney said the fast-moving fungus may have already done the damage.

"Next winter, we may not see much mortality because there may not be many bats left to die after this year," he said.

By 2012, white-nose syndrome had killed an estimated seven million bats in North America.