Karpanty sent Crowley bones from 19 lemurs she found at four goshawk nests.

Crowley also enlisted the help of lemur expert Andrea Baden, an assistant professor at Hunter College. Baden studies anthropological biology and has spent years following endangered lemurs in Ranomafana and other parts of Madagascar.

“It’s tough. We’re working in montane rainforest. A lot of people have a misconception that all tropical rainforests are hot. But this is cold and rainy. You’ll have months of nonstop rain. Everything is damp constantly,” Baden said.

Crowley has also explored this park on Madagascar’s verdant eastern coast.

“The cold and wet got to me quickly,” Crowley added. “I deeply respect the people who go into the forest and live there among the lemurs. I couldn’t do it.”

Baden studied a variety of lemurs, in particular the critically endangered black-and-white ruffed lemur.

“It’s cat-sized. They’re comical to watch. They’ll come down to check you out and cock their heads to one side like a dog,” Baden said.

Lemurs navigate the forest from the treetops. But the terrain is harder for their two-legged relatives on the ground.

“You’ll be following animals and they can keep going in the trees, but you run into a cliff edge and you’re stuck,” she said.

“Lemurs are the most endangered mammals in the world,” Baden said. “Unfortunately, what’s left of the forest in Madagascar are these higher-elevation places because nobody can use them for agriculture.”

Philip Slater of the University of Illinois and primatologist Summer Arrigo-Nelson with the California Institute of Pennsylvania also contributed to the study.

Baden and Arrigo-Nelson collected leaf and fruit samples of plants the lemurs were observed eating in different habitats and elevations in Ranomafana, recorded their location and shipped the dried specimens to Crowley for strontium analysis.

Researchers measured the ratio of strontium 86 and strontium 87 isotopes in lemur bones and the leaves collected from different forest habitats. These isotopes are released to varying degrees into streams and soil from the weathering of rocks. Plants absorb the strontium with other nutrients in the soil. Strontium then gets absorbed by animals when they eat the plants. In this way, the widely varying ratios of strontium isotopes creates a unique geographic signature.

By measuring strontium in lemurs and the many diverse habitats of the park, Crowley could infer where goshawks caught their prey.

Crowley used a similar analysis to track the movement of extinct mammoths and mastodons that roamed what is now Ohio.

Crowley said her findings suggest that vulnerable species could be susceptible to development pressures even in large parks such as Ranomafana, which is nearly 40 percent bigger than Ohio’s biggest protected area, Shawnee State Forest.

“We make population estimates based on the area of protected land, assuming that animals are equally distributed over that space,” Crowley said. “We may be protecting land that animals may not be able to use.”

The study concluded that conserving and restoring lowland forest could be critical for the survival of goshawks on the island.

The research was funded in part by grants from the Fulbright Foundation, the National Science Foundation, the U.S. Environmental Protection Agency, the Leakey Foundation, Primate Conservation, Inc., and the National Geographic Society.

Lemur expert Baden said the study’s findings support what she has observed firsthand about lemurs and their predators. Improving or restoring habitat for goshawks will help endangered lemurs, too, she said.

“Lemurs are in trouble. They’re in dire straits,” Baden said.

Habitat loss is the biggest cause of their decline. And now there is an emerging threat: the bushmeat trade.

“The Malagasy people have a taboo against hunting lemurs. It’s related to ancestor worship. They long believed that lemurs resembled their ancestors,” Baden said.

Still, a 2016 study published in the journal PLOS One found widespread consumption of bushmeat. And for at least some of the Madagascar families surveyed, lemur was on the household menu, the study found.

Worse, because of its rich deposits of precious metals such as gold and other natural resources, Madagascar has been called “the next El Dorado.” Foreign workers employed by mining companies have no cultural prohibitions against eating lemurs or other forest animals they poach, Baden said.

“Those taboos just fall apart. So now we’re seeing a bigger bushmeat trade that is completely unsustainable,” Baden said.

Karpanty said Madagascar can enlist the help of the goshawk for future conservation efforts. Predators such as bald eagles make good ambassadors for wildlife conservation, Karpanty said.

“It’s easier to motivate people to conservation action when you’re talking about interesting top predators,” Karpanty said. “In this case you have an endangered predator and endangered prey, the lemurs. It highlights the fragility of the ecosystem.”