Wedge-tail expert Nick Mooney said the endangered raptors now played a significant role in the state's ecosystem as a big predator.

Three decades ago there were thought to be only about 130 breeding pairs left in Tasmania - now Mr Mooney said there were about 400 territories (pairs) producing on average 220 young a year.

"In 2005, I thought Tasmania had the potential for about 450 territories but the eagle population of Tasmania 10 years ago was pressed by about 20 per cent from its potential," he said.

"So you have got about 400 territories, but a lot of them fail for natural reasons and a lot of them fail for human reasons.

"Essentially about 42 per cent of territories are in state forest, about 42 per cent on private land and about 15 per cent on reserved land of some sort.

"The areas where there is not much human influence, such as the south-west, there is not many eagles anyway because there tends to be poor productivity.

"In the last decade there has been a gradual improvement but it's not really a recovery in the birds, it is just we have much better information now."

Primary Industries, Parks, Water and Environment Department statistics indicate that there are 1854 different wedge-tailed eagle and white-bellied sea eagle nest sites recorded in the state.

The Forest Practices Authority run an eagle monitoring project that investigates the effectiveness of protective mechanisms in forestry.

Mr Mooney said eagles could have up to three eggs in a nest, however, the first born normally killed its siblings in a survival of the fittest act and that only 50 per cent of juveniles that made it out of the nest survived.

"Wedge-tailed eagles have to be four or five before they are sexually mature and if they can chew into a territory somewhere or replace another one, then their mortality drops to about 5 per cent a year and [they] are likely to live for 20 to 25 years," he said.

Mr Mooney said many eagles were once shot and killed by farmers as they would not tolerate any stock losses, but now the wedge-tailed eagle was protected under the Threatened Species Act and the Forestry Practices Plan.

He said those cases had diminished but threats to the eagle's wellbeing, such as disturbance, powerlines, vehicles and wind farms, remained.

He said one positive for the birds of prey was the fatal tumour diseases decimating the state's devil population.

"Because there are much less devils around; a major problem for eagles was farmers illegally poisoning devils and also killing eagles," Mr Mooney said.

"Now that doesn't happen because devils aren't such a nuisance and the accidental deaths of eagles are much less.

"I have been doing road counts on eagles since the early '70s and my counts are slightly up in areas where devils are down, as devils and eagles often compete for the same food.

"Not only have you got less eagles being killed accidentally, you've got more food for the eagles and with eagles that mainly attributes to the survival of the juveniles."

The Tasmanian wedge-tailed eagle is considered a sub-species of the mainland variety but recent DNA comparing the two challenges the findings.

Mr Mooney said although they did look slightly different, the fact Tasmanian birds were bigger was to be expected because of the state's cooler climate.

"To me whether they are an endemic sub-species is academic - their role as a top predator being far more important and arguably of increased importance in ecological stability since we have lost thylacines, devils are much reduced and are challenged by cats and the potential for foxes remains," he said.