Bird ringing started in 1948 in southern Africa and is thus the longest running bird monitoring project in the sub-region. Although the data are biased to areas where ringers operated, it is an invaluable record of bird occurrence and distribution changes, arrival and departure times of migrants, survival and mass data in historical times.The South African Bird Ringing Unit (SAFRING), which is an essential arm of the Animal Demography Unit, administers bird ringing in southern Africa.