The State of Maine has installed warning signs along some highways to save its eagle population from collisions with cars and trucks. 

The illuminated signs alert drivers when they are travelling through areas known to be home to nesting pairs of eagles.

Erynn Call, a biologist and raptor specialist, said the state has experienced a remarkable increase in its bald eagle population since the 1970s and is doing what it can to protect the birds. 

"The eagle recovery plan has been so successful the number of nesting eagle pairs in Maine has increased from 31 pairs in the ‘70s to over 600 pairs currently," Call said in an interview from Bangor, Me.

"Just to give perspective, in 1978 there were only 600 known nests in the entire lower 48 states where bald eagles were listed, so pretty incredible."

'Since the signs were deployed last year, there has not been a single bald eagle vehicle collision.' - Erynn Call, Maine biologist

During that period, Call said the eagles have been reclassified several times — from endangered to threatened in 1995. And then removed from the list in 2007 and listed as recovered in Maine in 2009.

But Call said bringing the birds back from the brink of extinction in Maine is presenting new challenges, especially to the travelling public.

"Bald eagles, as you may know, capture fish and waterfowl, but they are also scavengers and therefore they're attracted to carrion or roadkill along highways," she said in an interview.

"And if they're spooked or they decide to fly from the roadside, they tend to go toward openings, which is often the roadway. And just because of their large wingspan, the eagles start out pretty low to the ground when they start off and they can end up right at the height of a car or a truck."

The bald eagle is the national bird of the United States.

Specific areas selected for signs

Call said the Department of Inland Fisheries and Wildlife partnered with the Department of Transportation to come up with roadside signs to make drivers aware of bald eagles in certain areas of the state. 

They selected areas that were having recurring eagle-vehicle collisions, including the Medway area of the state, which is about 130 kilometres southwest of Woodstock, N.B., on the I-95.

The transportation department also works in those areas to remove roadkill as quickly as possible to diminish the attraction for eagles.

"It's been very successful," said Call.

"Since the signs were deployed last year, there has not been a single bald eagle vehicle collision."

Call said the United States considers preservation of eagles a priority and has listed them under the Bald and Golden Eagle Protection Act. 

Any motorists who do hit them are asked to report the collisions. The state collects any carcasses and ships them to the national bald eagle repository in Colorado.

"The remains are disseminated to native American tribes,” she says.

Call attributes the recovery of the eagle population in Maine to a number of measures including a sharp reduction in the use of chemicals, such as DDT, and strict conservation in 400 known breeding areas.

Scientists are also tracking their habitats with satellite transmitters.