Long-term research into wedge-tailed eagles in Western Australia's northern Goldfields has highlighted low breeding rates as a potential problem for the species.

Beginning in 2013 at Lorna Glen, a former pastoral station 700 kilometres north-west of Kalgoorlie-Boulder, the program has seen a number of eagles trapped and tagged for future monitoring.

Wallu was the first ever Wedge-tailed eagle fitted with a transmitter as part of the ongoing research. ( Supplied: Simon Cherriman )

Environmental biologist Simon Cherriman said the slow rate of population growth was the first major indication out of his initial three years of research.

"You assume birds lay eggs, have young and then fledge their young, then do the same thing each year," he said.

"But most of the pairs up there don't successfully breed at all."

Of the 35 pairs of birds he is currently monitoring, Mr Cherriman said only 10 would attempt to breed each season.

He said only half of those 10 would successfully fledge a chick.

"The productivity is very, very low," Mr Cherriman said.

"You need 35 mating pairs living for a few years to make 20-30 new eagles overall.

"So the death of even a few, by roadkill or other reasons, could be really important."

Native sanctuary attracted predators to area

Known as Matuwa to the area's traditional owners, Lorna Glen was re-established as a wildlife sanctuary by the Department of Conservation and Land Management in 2000.

Fencing has been periodically strengthened to ward off foxes, cats and other feral predators, with native populations of vulnerable and endangered animals progressively reintroduced since then.

Mr Cherriman said the question of whether the increased animal population would attract more eagles to the area initially sparked his research.

"We wanted to look at whether the place was acting as a magnet for eagles, to see if they were coming from all over the place," he said.

Wurru, Wallu's mate, is not tagged and can only be tracked by monitoring the other eagle's movements. ( Supplied: Simon Cherriman )

"We found there were many more pairs than we anticipated, so because of all the adjacent pairs in this area, I thought it would make a good ongoing study."

The animals are lured in with roadkill, trapped and fitted with satellite trackers before being released, allowing the biologist and his team to track their movements.

He said breeding and successful increases were closely tied to rainfall, with the adult birds largely sticking to a range of 5-8 kilometres.

"It's the pairs that get good rainfall in their territories, their the ones who breed and successfully fledge young," Mr Cherriman said.

Female eagle Gidgee was initially trapped in 2013 and has been closely monitored since. ( Supplied: Simon Cherriman )

Sanctuaries need careful planning

While eagles will successfully prey on any smaller mammals, Mr Cherriman said feral and invasive species were the larger ongoing threat.

He said the experience at Lorna Glen careful planning would allow vulnerable populations to successfully deal with native predators.

"[Some animals] did not have any habitat and were just sitting out in the open," Mr Cherriman said.

"They got eaten really quickly, but some of the other animals, like bandicoots, find refuge in the spinifex.

"The eagles will get a few, but not enough to knock them all off."

He said eagles were not likely to be a problem for animals outside their regular territory.

"Cats and foxes are the real threat," Mr Cherriman said.

He will present some of his findings at an environmental management workshop in Kalgoorlie-Boulder next month.