Reconciling agricultural production with biodiversity conservation. Группа авторов
countries of the European Union are characterized by a long-lasting tradition of bird-watching, on which scientifically grounded countrywide surveys were nested. Countries such as Finland, Sweden and Denmark organized a countrywide monitoring scheme in 1975, the United Kingdom in the 1960s. Others started later on, but nowadays all EU countries except Malta have a monitoring scheme in place.
In 2002, the Pan-European Common Bird Monitoring Scheme (PECBMS) was started as a joint initiative of the European Bird Census Council (EBCC) and BirdLife International, with the aims of: collecting data on European common bird species from national monitoring schemes and calculate European common bird indices and indicators, to raise awareness and to feed the policy process; support the national coordinators in setting up the schemes, and guarantee a harmonized approach in the calculation of the indices; explore the relation between population trends and main driving forces (EBCC, 2019).
Most surveys are carried out through point or line transect counts, where the selection of the plots to be surveyed (each plot containing one or more point or transect) is made either following rigorous statistical procedures (e.g. systematic selection, stratified random selection) or a free choice approach (Table 1). The surveyor visits the assigned location one or more times during the year, in predetermined time windows (e.g. 10 May–20 June as in the Italian survey), and records the individuals seen or heard. A thorough statistical analysis is followed to identify errors and outliers.
Table 1 Principal characteristics of national breeding birds monitoring schemes
| Country | Generic breeding bird monitoring scheme | Contributes to PECBMS | Start year | Field survey methods | Selection of plots | Number of species |
| Austria | Yes | Yes | 1998 | Point counts | Free choice | 85 |
| Belgium | Yes | Yes | 1990 | Point counts | Stratified random, other | 134 |
| Bulgaria | Yes | Yes | 2004 | Line transects | Stratified random | 63 |
| Croatia | Yes | Not yet | 2015 | Point counts | Stratified semi-random | 30 |
| Cyprus | Yes | Yes | 2006 | Line transects | Other | 45 |
| Czech Republic | Yes | Yes | 1982 | Point counts, line transects | Free choice, stratified random | 218 |
| Denmark | Yes | Yes | 1975 | Point counts | Free choice | 143 |
| Estonia | Yes | Yes | 1983 | Point counts | Free choice | 90 |
| Finland | Yes | Yes | 1975 | Point counts, line transects, other | Systematic, other | 140 |
| France | Yes | Yes | 1989 | Point counts | Other | 150 |
| Germany | Yes | Yes | 1989 | Line transects, point counts, territory mapping | Free choice, stratified random | 100 |
| Greece | Yes | Yes | 2007 | Point counts | Stratified random | 233 |
| Hungary | Yes | Yes | 1999 | Point counts | Stratified random | 420 |
| Ireland | Yes | Yes | 1998 | Line transects | Stratified random | 55 |
| Italy | Yes | Yes | 2000 | Point counts | Random | 103 |
| Latvia | Yes | Yes | 1995 | Point counts, territory mapping | Random, systematic, other | 90 |
| Lithuania | Yes | Yes | 1994 | Point counts | Stratified semi-random | 70 |
| Luxembourg | Yes | Yes | 2002 | Point counts, territory mapping, line transect | Random, stratified random | 120 |
| Malta | No | |||||
| Netherlands | Yes | Yes | 1984 | Territory mapping, point counts, line transects | Free choice, random, stratified random | 100 |
| Poland | Yes | Yes | 2000 | Line transects | Stratified random | 110 |
| Portugal | Yes | Yes | 2004 | Point counts | Stratified random |
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