2019

Conserving Kruger’s Martial Eagles

Martial Eagles are classified as Vulnerable on the IUCN Red List of Threatened Species, due to suspected population declines across much of their African range. Locally within South Africa, Lesotho and Swaziland the species is classified as Endangered owing to worrying population declines. In South Africa, it has been estimated that there could be up to 800 pairs of this magnificent eagle. However, recent findings by researchers at the University of Cape Town’s FitzPatrick Institute of Ornithology have suggested that the species has declined by up to 60% over the last 20 years. This is also the case inside the Kruger National Park, the largest protected area in the country, where it has been estimated that the species has declined by as much as 54%. These declines are very concerning and highlight the need for larger landscape conservation efforts to mitigate threats to large raptors.

 

In response to these declines, in 2013 the FitzPatrick Institute of Ornithology established The Martial Eagle Project, which is now run in collaboration with the EWT’s Birds of Prey Programme and is a registered SANParks project. The project aims to improve our understanding of the threats faced by this species and how these threats could be driving population declines of Martial Eagles, with a particular focus on the declines that have been observed within Kruger, where species are usually expected to be most protected. This research is important to understand the role that protected areas have in conservation and to understand specific threats and habitat requirements for the conservation of Martial Eagles.

 

At the outset of the project, one hypothesis for the population declines was that immature Martial Eagles might be subject to increased mortality outside of protected areas, due to the tendency for inexperienced eagles to range into areas with increased human pressures. This would cause a reduction in the number adult birds that are able to recruit into the breeding population in Kruger. The good news is that contrary to this hypothesis, GPS tracking data collected since 2013 did not find evidence for low survival during these early life stages despite ranging widely beyond protected area boundaries.

 

However, through GPS tracking of adult birds and nest monitoring, two potential factors that may be contributing to the observed population declines have been detected: low adult survival and poor breeding productivity. Adult mortalities, including persecution and electrocution, during unexpected wide-ranging movements outside of the Kruger, might be a major factor contributing to population level declines.

 

The poor breeding productivity recorded by the project from 2013 to present comes in two forms: both a lower than average number of pairs making a breeding attempt and low success of those pairs which do try. To better understand the latter, the project has recently been installing time-lapse cameras at nests, which will record the actual causes of nest failure. Cameras are currently installed at active nests and at the end of the breeding season in November, they will be recovered so we can learn something more about this year’s nesting attempts. Alongside this, the project is continuing to investigate individual eagles’ movements and survival in the Kruger using GPS tracking.

 

In order to conserve a species we need to understand its requirements, how it interacts with the environment, and the threats that it faces. Thus, the information gathered by the Martial Eagle Project will all contribute to the goal of long-term conservation of this wide-ranging top predator.

 

Dr Gareth Tate, Manager, EWT Birds of Prey Programme

 

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