David Allan, Durban Natural Science Museum
Left: A close-up portrait of an immature Crowned Eagle; right: An adult Crowned Eagle in flight (photos: David Allan).
In late January 2021 our Museum received a request from Dr Shane McPherson from the University of KwaZulu-Natal concerning information about the causes of mortality in the Crowned Eagle specimens we have in our collection. This species is considered formally threatened (classified as ‘Vulnerable’) and the information was for a scientific paper aimed at identifying mortality factors in this species, especially in urban areas. Shane has kindly donated several Crowned Eagle specimens of birds found dead to the Museum over the years of his study.
We have 13 study skins and three eggs of this large eagle in our collection. In addition, we have a further three frozen specimens and a skeleton in our freezers awaiting preparation and accessioning to the formal collection.
Left: A sub-adult Crowned Eagle killed when it flew into the window of a skyscraper – note the partially shattered glass of the window in the upper left (photo: David Allan); right: An adult Crowned Eagle struck by an aircraft at King Shaka International Airport (photo: Shivanie Sudu).
Information on causes of mortality is available for five of the specimens:
- A sub-adult flew into the window of a skyscraper in central Durban on 3 Jun. 2008 (apparently while being harassed by Pied Crows).
- A young bird was electrocuted in Giba Gorge, Durban, on 19 Nov. 2010.
- An adult was hit by an aircraft at King Shaka International Airport in Durban on 6 Sept. 2012.
- A young bird was electrocuted at Mount Moreland in Durban on 13 Dec. 2012.
- An adult was hit by a car on the busy M13 in Kloof, Durban, on 26 Sept. 2018.
Three additional records of mortality in this species were also found in our files here at the Museum (although sadly these specimens never made it to the Museum):
- An adult killed when it apparently caught its leg in a tree fork in a dense forest near Ballito north of Durban on 25 Sept. 2006.
- A young bird was shot in Pietermaritzburg on 12 Dec. 2012.
- A young bird was shot in Hilton near Pietermaritzburg on 9 June 2011.
These records reflect several perils faced by these birds in human-modified habitats, including collisions with buildings, vehicles and aircraft, electrocution and intentional persecution in the form of shooting. There is a strong indication that it is young, inexperienced birds most at risk of human-induced mortality (five of eight instances).
Three Crowned Eagle study skins in the Museum collection. The upper bird, an immature, was killed by electrocution, the bird in the middle, a sub-adult, was the skyscraper-window collision victim (see photo above), and the lower bird, an adult, was hit by a car (photo: David Allan).
It is important to document the causes of death of specimens such as this which are donated to museums as this information can be invaluable in informing conservation efforts aimed at these birds. For example, the hazardous electrical infrastructure responsible for electrocutions can be modified to render them safe for large birds perching on these structures.