Looking for Tawnies in Karoo, South Africa

16 June 2021

Tawny Eagles occur throughout much of Africa and South Asia, however rapid declines have been reported across their African range. These declines have warranted the up-listing of their conservation status on the IUCN Red List to Vulnerable in 2018. The exact cause of these population declines is largely unknown, however, changing environmental conditions and poisoning are likely to have both played a large role. Tawny Eagles eat a wide variety of prey such as birds, small mammals, and reptiles, in addition to scavenging extensively. This exposes them to poisoned baits, which are also responsible for catastrophic declines of African Vultures.

Tawny Eagles can occupy a range of habitats from open savannah to lightly wooded areas and they usually build a large stick nest in the crown of thorny trees. But at the southern tip of their range in the Karoo, South Africa, there are no large trees and since around the 1970s, Tawny eagles have taken to nesting on the steel lattice pylons supporting medium and high voltage electricity lines. This has been a population expansion and very little is known about their local population size and long-term viability. Therefore, HawkWatch has set out to investigate the regional population estimate, population trend, and conservation requirements.

Below is a report from Dr. Meg Murgatroyd on her most recent trip into the field.

Verreaux’s Eagles are the most common large eagle in the Karoo region. They nest on an abundance of small cliffs and koppies (another word for hills), as well as taking to the power pylons more recently. Martial Eagles have also taken to nesting on the pylons over the past few decades and the Endangered Wildlife Trust has been undertaking some excellent research to understand their population dynamics in the area. Smaller than these two species, the arrival of Tawny Eagles has gone relatively unnoticed, but they too now nest on pylons in the absence of any major trees. 

My first day looking for Tawnies here went pretty badly. The first nest I visited simply wasn’t there. I was excited to spend some time watching this species for the first time, so I felt deflated as I arrived at the correct pylon only to find nothing. I don’t know when it was last recorded as active, but I can’t deny my disappointment and reality check. After this, I met up with a farmer who knew the location of a Tawny nest on his land. He pointed to a large nest on a pylon and I was slightly surprised that he so confidently knew it was a Tawny nest. I later found out that he had found a dead Tawny Eagle underneath it so he was sure it belonged to the Tawnies! Undeterred and hopeful, I set up my telescope on a nearby hill for a good vantage and settled in for the wait. I waited… and for that afternoon I didn’t see any eagles other than one Martial cruising in the distance.

The next day, I positioned myself on another hilltop with a good vantage of another nest at least a mile away from where I sat. It was one of those stunning mornings where I was quite happy to sit and wait. But during my three-hour watch, I didn’t see an eagle go to the nest. However, I did finally see my first Tawny Eagle in the Karoo. It was a fleeting sighting as it chased off a passing Verreaux’s Eagles, and briefly soared with what I can only assume was its mate. Despite being brief, it was rewarding enough, and their territorial behavior gave me hope that this was indeed their home. 

The following day I passed the first nest again and got the sighting I really wanted: a pair of Tawny Eagles standing on a nest. So despite the earlier death of one of the eagles, there was indeed a resident pair here too. Although they don’t seem to be breeding right now, I am already scheming on how I will track these eagles… hopefully, another story for another day.

This trip was the first exploratory trip for this research and I have now visited 5 Tawny Eagle nest locations. Although none of them were actively breeding, they are possibly the southernmost nests for the species and I’m excited to begin this journey with them.

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