How do you track a secretive hawk? Follow the isotopes

Isotope research could help steer the conservation of many threatened species

Date:  December 11, 2017

Source:  University of Cincinnati

University of Cincinnati professor Brooke Crowley wanted to know the hunting range of the Henst's goshawk, a large forest-dwelling bird of prey that ambushes small animals.

Henst's goshawks are difficult to find because of the rugged, inaccessible forest where they live. Little is known about their population. But because of their limited distribution, they are listed as near-threatened with extinction by the International Union for Conservation of Nature and Natural Resources.

Locating even a single goshawk nest required weeks of exploration by Crowley's research collaborators.

So Crowley decided to conduct an elemental analysis using strontium, naturally occurring isotopes found everywhere on Earth that travel the food chain from the soil to plants to herbivores and predators.

Specifically, Crowley compared the ratio of strontium 86 and strontium 87 isotopes in rainforest leaves collected across Madagascar's Ranomafana National Park to isotopes found in the remains of 19 partially consumed lemurs collected in or around goshawk nests to learn where the birds of prey were hunting.

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