Wildlife enthusiast Duncan Barnes took this photo in South Africa of a martial eagle called Red A0. Scientists there noticed a decline in the majestic bird, and they asked people to help them track the animals by sharing images on social media with the location tagged. (Duncan Barnes)

Scientist Megan Murgatroyd spends much of her time studying martial eagles, the biggest bird of its kind in Africa. She loves their intelligence and power. With a wingspan of more than six feet — the distance wing tip to wing tip — they can soar for hours.

But in the past few years, Murgatroyd and other scientists in South Africa noticed a drop in the number of martial eagles there. (The International Union for Conservation of Nature lists the bird as vulnerable to extinction.) As scientists tried to figure out why the numbers were declining, they asked people throughout the country to help by taking photos whenever they saw one of the birds and “tagging” their pictures with a location on social media.

The researchers have followed up on sightings, with the goal of getting a better estimate of the size and whereabouts of the martial eagle population. (The birds are territorial and respect one another’s boundaries, which makes tracking them easier.)

“It is pretty much a case of connecting the dots,” said Murgatroyd, who is a conservation biologist with the organization HawkWatch International. “The public is helping us to connect the pieces of this puzzle.”

Scientist Megan Murgatroyd tags and measures an eagle. She says the public’s help has been “invaluable.” (Photo courtesy of Megan Murgatroyd)

More than 1,200 people follow the initiative on Facebook. Some posted photos they had taken at Kruger National Park, a huge reserve where many martial eagles are outfitted with devices allowing scientists to follow them. Others emailed pictures. The photos show eagles in flight and in treetops. Some birds held food they had captured in their long talons.

Several birds known to scientists were spotted again. Murgatroyd explained what happened in one case. It involved a bird named Red A0, in keeping with scientists’ approach of identifying their subjects using colors, letters and numbers. He had been tagged in 2017 and fitted with a leg ring and GPS tracker.

“Often we put cameras in the nests,” Murgatroyd said. But Red A0’s nest was too high in a tree to reach. Then in May, a man took “a beautiful sunset photo of him” in Kruger and tagged it online. Scientists went back to his nest and, after some tough climbing to get a better view, found that Red A0 had a mate and that the pair had a chick. Murgatroyd is hoping future pictures from the public will reveal more about the family’s well-being.

A martial eagle perches high atop a tree. Some of the social media posts led scientists to find the birds’ nests. (Ralph Buij)

“The public’s input is invaluable,” she said. “Visuals of the tracked birds allow us to see that all is well and good. You can’t tell that from tracking data.”

She said four nests were found through Instagram photos this year, and 21 occupied nests were watched.

Still, “we have yet to learn many of the species’ secrets,” Murgatroyd said.

The research team, which involves her HawkWatch organization, the Endangered Wildlife Trust and the FitzPatrick Institute of African Ornithology, still doesn’t know why the eagles’ numbers are falling in South Africa. Climate changes could be one reason, she said.

These aren’t the only eagles that fascinate her. She’ll soon travel to the southern part of the country to study the Verreaux’s eagle in a semidesert area called the Karoo. And next year, she will fly to the United States and do research in Utah. Murgatroyd’s target there? The golden eagle.