What is bird ringing and why are birds ringed?
Answers
Bird ringing is a useful research tool providing information on the survival, productivity and movements of birds, helping us to monitor bird populations and to understand why they are changing.
The original purpose of bird ringing was to solve the mysteries of bird migration. Bird ringing for scientific purposes started in Denmark in 1889, when Hans Christian Cornelius Mortensen released starlings that were fitted with metal rings engraved with successive numbers. In a very short time ringing shed light on the complicated migration routes of many migrants and as early as 1931 the first atlas of bird migration was published. Nowadays, within Europe the broad patterns of migration are now known for most bird species.
Ringing birds is essential in order to know how long they live and when and where they move, questions that are crucial for bird conservation. The uniquely numbered metal ring which is placed around a bird’s leg provides a reliable and harmless method of identifying birds as individuals.
In addition, bird ringing is very important for the study of migratory birds and their conservation because it allows to track the movements and other life history traits of the birds over time. The identification of birds helps to identify the crucial sites along their migratory routes and provides important information for conservation planning and site management. Moreover, through ringing we have the opportunity to obtain information regarding the dispersal, migration, longevity, behaviour, survival rate, reproductive success and population trends of migratory birds. Therefore, all this information helps us to get a better insight of the birds’ biology and ecology and their demographic changes over time giving the opportunity for successful conservation measures to be adopted.
Bird ringing can be useful as a monitoring technique and to understand population dynamics and persistence. Furthermore, it is used in evolutionary and behavioral studies (e.g. inbreeding in the wild, the existence of infanticide, foraging strategies) and in studies for bird-transmitted diseases (e.g. avian influenza virus of the H5N1 type).
Despite the benefits of bird ringing, it is very important the ringing to be done from experienced ringers who have gained the required license after training, in order to ensure the safety of the birds. Furthermore, ringing requires delicate handling and experience on how the bird will be held, how the ring will be placed on the bird’s leg without injuries and how the different morphometric measurements (e.g. wing and tail length, fat score, mass) will be done.
The information derived from ringing usually belongs to three categories: geographical, demographic and biological status. Geographical data provide evidence for which habitats within a breeding territory a bird preferentially selects for foraging and for the migration routes and the important stopover sites (with Cyprus to belong to one of them). Demographic data such as data on the population processes of productivity, survival and immigration/ emigration can interpret population changes by linking differences in demographic rates with environmental changes. Finally, biological status data can provide information on environmental conditions experienced by the individual bird, or its ancestors. For instance, the diet composition of a bird over the few hours prior to trapping can be known as well as the evolutionary relationships and current taxonomy which are deriving from the genetic information from biological samples.
There are a lot of studies showing that ringing can play a key role in answering a variety of research questions. The importance of migration flyway networks of wintering and stopover sites for waterbirds has been highlighted by ringing studies. Such ringing data have been central to many international efforts to create networks of key protected areas along these flyways, and has helped establish the principle that such migratory populations can be sufficiently protected only by coordinated multinational conservation action.