African Wildlife & Environment Issue 77 FINAL ISSUE

BIRDING

Breeding Breeding behaviour is triggered by rain, and extends from September to May but mainly from November to February. This goose breeds in tropical and subtropical woodland / wetland mosaics, usually on a site not more than 0.5 km from where the water lilies ( Nymphaea spp ) or pondweed ( Potamogeton spp ) cover fairly deep, clear freshwater pans, lakes, dams, sluggish rivers and open waters of swamps and old marshes. Nests often overhang the water. The nest site on average is 4 to 6 m above the ground, with the highest recorded nest being as much as 20 m. Usually a cavity in a tree is utilized, up to a depth of 600 mm, with an entrance of around 70 mm or more in diameter Hollow trunks that have been chopped open by honey gatherers are commonly used. Other sites include artificial logs, holes in a rock face, termite mounds, on thatched roofs, palm crowns and inside abandoned Hamerkop nests. These geese are often seen clinging to trees like woodpeckers, as they search for nesting hollows. The nests are often lined with dry grass and white down feathers supplied by the female.

The feathers are also used to hide the eggs when the female goes out to feed with the male a few times a day. Seven to nine eggs, creamy white/ ivory to pale brown, are laid in a clutch at one to two-day intervals. Incubation is around 24 days. The chicks leave the nest a day after hatching and are cared for by both parents. Young birds start flying around 42 days after leaving the nest Conservation status The conservation status of this species is 'Vulnerable' in South Africa, due to the destruction of limited suitable habitats. This is mainly due to the degradation of wetlands and interference with flood-plain ecology, such as the building of dams. Invasive alien species like Water Hyacinth are drastically reducing the availability of open surface water and impacting on their numbers.

John Wesson jwesson@wessanorth.co.za

45 | African Wildlife & Environment | Issue 77 (2020)