How far and how old: Longevity and displacement records from the South African Bird Ringing Scheme for Ardeidae, Threskiornithidae and Ciconiidae
Keywords:herons, storks, egrets, longevity, displacement, migration, life history, avian
Background: Understanding the movement and displacement of individuals within avian species is important for conservation. Herons, Storks and Egrets are especially important as they are migratory species and are potential indicator species. It is therefore valuable to set life history baselines to understand survival.
Objectives: To establish baseline longevity and displacement values for the avian families Ardeidae, Threskiornithidae and Ciconiidae using the South African Bird Ringing Scheme (SAFRING) data for Africa and to highlight gaps in the SAFRING database for these families.
Method: We used data archives of ringed and subsequently reported individuals to determine maximum displacement and longevities from the past seven decades for each species within these three families. Displacement was estimated by the straight-line distance between subsequent records for the same individual. Longevity is the measure of time elapsed in records for the same individual.
Results: Displacement and longevity data were available for 17 of the 24 species in the focus families. Individuals of most of the species were ringed as nestlings so displacement records may represent dispersal. Displacement ranged from a maximum of 10114 km for a White Stork (Ciconia ciconia) to 2.5 km for a Little Bittern (Ixobrychus minutus). Several species are poorly sampled, resulting in longevity records of just a few days. Despite that, longevity values were > 5 years for 16 species, and the highest value was 25.3 years for a White Stork.
Conclusion: It was possible to determine longevity values for most of the species within the three families investigated.