Définition
This indicator, also known as the Temporal Monitoring of Common Birds (“STOC”) index, monitors changes in populations of generalist and specialist breeding birds in agricultural, forestry and built-up areas in metropolitan France over time and space, thanks to a standardised protocol.
The measure is coordinated by the Muséum National d'Histoire Naturelle (MNHN) and is based on the participation of both amateurs and professionals who, every year, identify and count the species present in metropolitan France. The listening areas are widely distributed and abundantly sampled within the framework of the protocol for the Temporal Monitoring of Common Birds by Simple Punctual Sampling, (“STOC-EPS”) which excludes by nature nocturnal common birds, for example.
Since 1989, the “STOC” programme (Temporal Monitoring of Common Birds), coordinated by the MNHN, has been providing standardised monitoring of breeding populations of common birds. Field surveys are carried out by a network of citizens who are in charge of monitoring the species present in a defined territory (mesh size: 2 km x 2 km) each year. The observer identifies on this area, 10 counting points homogeneous and proportional to the habitats present on which he carries out two surveys in spring (4 weeks of intervals between each survey carried out before and after the date of 8 May, in the morning 1 h after sunrise in order to avoid the morning chorus of the birds; duration of the survey: 5 min). These surveys, carried out each time at the same locations, on the same dates and with the same weather conditions, cover both the habitat and the species contacted. They are transmitted regularly by the ornithologist via the Vigie-plume platform. Currently, 90 departments are covered by this monitoring.
From the information transmitted, the MNHN calculates indices of the evolution of avifauna populations (75 species of common birds identified). These include, for example, the skylark (Alauda arvensis, typical of agricultural environments), the spotted woodpecker (Dendrocopos major, typical of forest environments), the house sparrow (Passer domesticus, in urbanised areas) or the blackbird (Turdus merula, a generalist species). Population trends are calculated from a linear regression over the period 1989-2017.