High productivity by Fish Eagles on a polluted dam near Harare

Mundy, P.J. & Couto, J.T. 2000. High productivity by Fish Eagles on a polluted dam near Harare. Ostrich 71 (1 & 2): 11–14.

Lake Chivero, in the Robert McIlwaine Recreational Park west of Harare, is the capital city's main reservoir of drinking water. It has been the subject of five surveys for pesticides and/or heavy metals in the period 1974–1995. The (geometric) average DDE residue level in seven Fish Eagle eggs collected in 1980 was 53 ppm dry weight. By 1995, DDT levels had considerably declined. There are now five pairs of Fish Eagles on Lake Chivero (1996), at a very low density of 14.8 km shoreline per pair. In the 14-year period, 1984–1997, 40 pair-occupations have been found and inspected, which produced 64 fledglings. One nest had fledglings in 11 years, and on three occasions broods of three were produced from it. A fourth brood of three was produced at another nest. The dam receives treated sewage effluent from the city and is now highly eutrophic; this has contributed to the eagles' breeding performance.