African Wildlife & Environment Issue 80

BIRDING

Behaviour African Skimmers fly in lines over preferably calm waters and dip their lower mandibles in the water to feed.When the mandible touches a fish, the skimmer snaps its beak shut without missing a wing beat. They feed mostly at dawn and dusk and have good night vision. The birds will rarely stand in shallow water and sift for food with their bills. Food Fish is the main diet up to eight cm long, with the following species

being recorded as main prey:Tetras,Tilapia, Barbel, Elephant fish, African pike, Lamp-eyes and Ray- finned fish. Insects and aquatic crustaceans are

also taken. Breeding

African Skimmers nest in loose colonies on large sandbanks, free of vegetation and occasionally next to big lakes. The colonies typically consist of 20 to 60 pairs nesting, and each pair lays 2–3 (rarely 4) eggs in a deep unlined scrape in the dry sand. They usually commence nesting in June. Nests are sited 10-20m apart. Sites are re-used in successive seasons providing they are still free of vegetation. They are aggressive towards potential nest predators and often resort to distraction displays and false brooding. The young when threatened bury themselves in the sand. The nestling/fledgling period of the African Skimmer is 5-6 weeks and both parents incubate. Sometimes African Skimmer colonies are mixed with those of other sandbank nesting birds such as Collared Pratincole, Pied Avocet and White-fronted Plover. Skimmers are hostile in nature and live together in small colonies in pairs. Pairs keep growing their territories within

African Skimmers are partial intra-African migrants; they arrive in southern Africa when the water level of rivers starts falling at the beginning of the dry season, April–June, returning northwards after breeding when rivers start rising again at the start of the rainy season in November–January

56 | African Wildlife & Environment | Issue 80 (2021)