The following is an update from Shane McPherson, doing the studies on the urban Crowned Eagles.
Dear Hillcrest Conservancy
I have been in South Africa for 2.5 years now and have an amazing experience studying the local Crowned Eagles. As of early July I had submitted my Masters of Science thesis, which contains two data chapters including information of the nest site preferences and on the diet of urban eagles.
Several other components of the research are still ongoing including the telemetry studies, breeding success of eagles over three seasons, more id ringing of nestlings, and investigating further juvenile behaviours including dispersal, mortality, and pet attacks. I am currently working towards establishing myself here for another few years, which may include converting the current research to a PhD thesis with all this data.
A summary of the data that is currently being examined in the MSc thesis includes:
The nest characteristics of 46 sites were described. Half of all nests are in Gum trees. Black sparrowhawks, gymnogenes, and fish eagles also nest in gums. This provides interesting management conflicts for the municipality and conservancies. Ideally then I recommend that small patches (20 tall trees) of gums are left as raptor nest refugia approximately every 1km along the DMOSS stream systems.
Within a 500 sqkm area from Kenneirth Stainbank to KwaDebeka and inland to Drummond and Shongweni, there are no less than 20 active breeding pairs and perhaps as many as 27. This year I hope to search in these gaps to find more. Nests are spaced on average 2.5km along the DMOSS stream catchments which is similar densities to the most pristine natural forests. This is very surprising. But is perhaps reflected in the abundant prey available in the city.
Contrary to typical trends, Durban appears to offer a great amount of prey that Crowned Eagles can use. We used a very effective camera-trap technique to assess urban prey. 1,200 days on continuous timelapse footage was obtained from 11 urban nests (that’s over three years of daily data). We were able to identify to species 85% of the 836 animals delivered to the nest. 42% of all prey during the breeding season is dassies, with 19% being hadeda ibis nestlings. Blue duiker, and vervet monkeys are also important prey with chickens 5th most important at 3% of the prey. Not one dog was recorded delivered to the nest of a breeding eagle, and cats accounted for 0.8%. This data has found that 93% of prey during the breeding season is wildlife.
The discussion on cats and dogs must be then focused towards the behaviours of the juvenile and dispersing young eagles. We are aware that the most frequent pet-attacks occur when young eagles have been habituated and fed by well-meaning citizens. Further research and data will be carried out to work alongside the municipality, conservancies, KZN wildlife officers, and the public to try and educate best practices and how best to protect pets and manage ‘problem’ eagles.
At this stage the best practice is to talk with concerned people on a case by case basis and do everything possible to prevent sensationalising pet attacks in the local newspapers. To date Three young eagles have been recovered shot dead, including the ‘2012 Sarnia’ juvenile within Springside Reserve itself (shot with a .22). Four young eagles have been electrocuted and one adult male died colliding with a wall at 4am in March 2014.
From the public and the members of the conservancies I would like to please ask for your reports whenever young eagles are seen – especially to remind you to look and photograph their legs for the yellow ID tags. This behaviour and movement data is now a future focus of the research. The research is also gaining positive publicity of the eagles via the facebook page at facebook.com/Crowned EagleResearch.