Majestic martials take a dive

Recent studies have found that South Africa’s martial eagle population has spiraled by 60% in the last 20 years. Andy Wassung spoke to the experts…

“There has been a 54% decline in the Kruger National Park’s martial eagle population in the last 20 years”

For many nature lovers, Africa’s largest bird of prey needs little introduction. The majestic martial eagle, weighing up to 5.2kg with an enormous wingspan of over two metres, can typically be found perched atop a leadwood tree or, just as typically, soaring in search of its next meal.

Research, however, paints a far less typical picture of this apex predator, with the International Union for Conservation of Nature (IUCN) uplisting the species to Vulnerable in 2017.

“The reality for these birds is quite concerning, particularly in the Kruger National Park where there has been a 54% population decline in the last 20 years,” says John Davies, project coordinator for Raptor Conservation and Research at the Endangered Wildlife Trust (EWT).

One of the causes for concern, according to Davies, is the fact that birds are particularly susceptible to threats like pollution and habitat loss, among others. “With so little still truly understood about this species, there is a definite need to better understand the drivers behind these declines.”

Davies recently joined the Martial Eagle Conservation project in the Kruger where the team completed a two-week survey across the park, in which they checked more than 20 nests and found three more. Martial Eagle Conservation Project manager, Dr Megan Murgatroyd explains, “The main aim of the trip was to install nest cameras to gain insights into the causes of breeding failure. To do this we were looking for nests which looked likely to be active this year, in trees which were strong enough to climb safely –  usually leadwoods. We found seven nests that were suitable for our cameras.”

The team has also been using GPS technology to better understand the movements of their increasingly-elusive subjects. “GPS tracking has given us insights into nest locations, which are often difficult to locate in the bush, and it’s helped us to understand habitat preferences too,” Murgatroyd says.

Finding an active martial eagle nest is just one part of the challenge, while setting up a nest camera is another. “The installation involves us setting up a climbing line adjacent to the nest and rigging a camera trap with an additional external battery pack hidden away. This allows cameras to run for several months without us having to interfere, allowing the birds to breed undisturbed whilst we collect data,” explains Davies.

Some of the additional data they hope to access through the nest cameras include incubation and nestling periods, prey preferences as well as the amount they eat.

The Martial Eagle Conservation Project is a collaboration between the FitzPatrick Institute of African Ornithology, the Endangered Wildlife Trust and South African National Parks, supported by ABAX and the Ford Wildlife Foundation.

Do you share a love of this regal raptor? If you’re lucky enough to see one of the eagles which have been colour ringed or GPS tagged by the project, get in touch with the team and send photos to martialeaglesightings@gmail.com. Follow “Martial Eagle Conservation – Kruger National Park” on Facebook for more information and updates from the field.

Martial eagle facts

• 2kg: The martial eagle is Africa’s largest bird of prey, weighing up to 5.2kg with a wingspan of up to 2.4m.
•  1 egg: Breeding typically happens biennially, yielding a single egg.
•  8 months: Juveniles depend on their parents for food for as long as eight months.
•  6km: Their eagle-eye vision allows them to see prey up to 6km away.
•  60%: The countrywide decline in martial eagle numbers over the last 20 years.