Harpy eagles are considered by many to be among the planet's most spectacular birds.
They are also among its most elusive, generally avoiding areas disturbed by human activity - therefore already having vanished from portions of its range - and listed by the International Union for the Conservation of Nature (IUCN) as being 'Near-Threatened'.
However, new research led by the University of Plymouth (UK) suggests estimates of the species' current distribution are potentially overestimating range size.
Using a combination of physical sightings and environmental data, they developed a spatial modelling framework which aims to estimate current and past distributions based on the birds' preferred habitat conditions.
The authors then used the model to estimate a current range size 11% smaller than that referenced by the IUCN, with high climatic moisture being the most important factor influencing distribution, followed by a minimum temperature of the warmest month of approximately 27°C.
Based on past and future climatic projections, the researchers showed that harpy eagle distribution will remain stable in the central Amazon, Guyana, eastern Colombia, and Panama, making these regions especially important for their conservation.
In order to ensure their future persistence, the authors suggest current and future conservation policies such as reducing deforestation and addressing issues of persecution should take such spatial models into account.
The research is published in the journal Ecology and Evolution, and involved an international collaboration of researchers from The Peregrine Fund (Ecuador, Panama, USA) and the University of KwaZulu-Natal (South Africa), based in Brazil.
Harpy eagles are among the world's largest and most powerful eagles and historically ranged across lowland tropical forests from Mexico in the north to Argentina in the south.
However, they became locally extinct in parts of Central America and Brazil during the 20th century. Currently there are multiple conservation programmes in place to better understand population dynamics and conserve rainforest habitat to help ensure its future survival.
- The full study - Sutton et al. (2021): Geographic range estimates and environmental requirements for the harpy eagle derived from spatial models of current and past distribution, is published Open Access in Ecology and Evolution. 11: 481-497, doi: 10.1002/ece3.7068.
