Ringing IN THE Changes

Sandwich Terns in South Africa

- THEUNS KRUGER

Sandwich Terns Thalasseus sandvi-censis are common non-breeding summer visitors found along the entire length of the South African coast, where they are usually seen in the company of Common and Swiftterns as well as gulls. The number of Sandwich Terns that visit South Africa annually is estimated at between 10 000 and 15 000, which equates to less than 10 per cent of the population in western Europe where they breed.

These terns have been ringed in Europe and the British Isles for more than 100 years and rings have been recovered in South Africa from dead and captured birds over many decades. Although they provided useful information relating to the origin and age of the birds, they gave limited insight into the full life history of Sandwich Terns, including how many times and when a specific bird has been to South Africa. This situation has changed drastically over the past few years as a result of changes in ringing practices.