Swift Tern
(Great Crested Tern)
Geelbeksterretjie
Thalasseus bergii

The Sasol Birds of Southern Africa Field Guide says about the Swift Tern, "A large tern with a long, slightly drooped yellow or greenish-yellow bill (not orange, as in a Royal Tern…" So, noting its orange bill, I thought that this was a rare (for South Africa) Royal Tern. However, I have been advised that it the bird is actually a Swift Tern with an unusually orange bill.

Ruff