Contents: 2.1. Delivery of national data to PECBMS coordination unitCoordinators of national monitoring schemes deliver their national data to the PECBMS coordination unit annually. For information on data and contributing countries see Box Participating countries. 2.2. Combining national data into supranational 2.3. Types of supranational results that PECBMS producesSpecies indices and trends are produced for Europe and its regions (Central & East, North, South, West, and Southeast Europe, East Mediterranean and West Balkan) and for EU and its regions: New (since 2004) and Old EU Members States).
2.1. Delivery of national data to PECBMS coordination unit
Box Data checks
Box Participating countries
2.2. Combining national data into supranational outputs
Box Missing values II
2.3. Types of supranational results that PECBMS produces
The data delivered are: the national yearly indices per species, the all-sites yearly totals (= the sum of birds counted across all sites per year) and their standard errors, and the covariances between the yearly figures.
Specifically, national coordinators deliver two files per species - so called out and ocv files (see paper by Pannekoek & Van Strien, 2001 or also see website of Statistics Netherlands) - both produced by TRIM when calculating species indices at the national level. These TRIM output files are accompanied by a species list and by comments indicating any potential problems in the data. These comments are taken into account in further data analysis.
National data are checked for their quality using quantitative criteria (see Box Data checks).
outputsA method has been developed to produce supranational yearly totals and their standard errors across countries by combining the national data. The method takes into account the differences in population sizes per country, as well as the differences in field methods and in the numbers of sites and years covered by the national schemes. Instead of deriving the standard errors in the usual statistical way from count data and model fit, standard errors (and the year-year covariances) that resulted from the calculation of the all-sites totals per country were applied. The results are similar to those that would be produced when the raw data are being used (Van Strien et al, 2001).
To produce supranational indices, the national all-sites totals per species as assessed in the national monitoring schemes are combined. A weighting factor is introduced to adjust for differences in national population sizes, to make sure that a change in a larger national population has an accordingly greater impact on the overall trend than a change in a smaller population. The weighting factor is calculated as the national population size derived from BirdLife International (2015) in 2008-2012 divided by the average of the all-sites totals for 2009-2011. This weighting factor is applied to all other years of the scheme. By this weighting, the yearly scheme totals are converted into yearly national population sizes.
The national European monitoring schemes have started in different years, leading to missing national all-sites totals. An adapted version of TRIM is used to estimate the missing country totals, in a way equivalent to imputing missing counts for particular sites within a country. After these weightings and imputation steps, the national totals are summed up to European totals.
European species indices for a species are computed if data are available from countries which together host at least 50% of the ´PECBMS European´ population of that species. ´PECBMS Europe´ is EU 27 + Norway and Switzerland and consists of those countries which already deliver their data to PECBMS or are supposed to do so in the near future: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Netherlands, Norway, Poland, Portugal, Republic of Ireland, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, United Kingdom.
However, some parts of these countries (states) were excluded, mainly because of their far distance to the mainland of Europe: Faroe Islands and Greenland, Svalbard, Azores, Madeira, Canary Islands, Gibraltar.
Population species trends (multiplicative slopes) are computed and classified in the same way as at the national level.
The species indices are always computed for maximum time period given by the country with the longest data set within the region (e.g. indices for West Europe are produced since 1966 given by the starting year of the indices from UK, while indices from South Europe are produced since 1989 given by the starting year of indices from France - see an overview below).
Overview showing list of 28 countries, their start years and region that each country belongs to:
Country/region Region(group of countries) First year Last year Austria WE 1998 2015 Belgium-Brussels1) WE 1992 2015 Belgium-Wallonia1) WE 1990 2015 Bulgaria SEE 2005 2015 Cyprus2) East Mediterranean 2006 2015 Czech Republic CEE 1982 2015 Denmark WE 1976 2015 Estonia CEE 1983 2015 Finland NE 1975 2015 France3) SE 1989 2014 Germany East4) CEE 1991 2015 Germany West4) WE 1989 2015 Greece SEE 2007 2015 Hungary CEE 1999 2015 Italy SE 2000 2015 Latvia5) CEE 1995 2015 Lithuania CEE 2011 2015 Luxembourg WE 2009 2012 Netherlands WE 1984 2015 Norway6) NE 1996 2015 Poland CEE 2000 2015 Portugal SE 2004 2014 Republic of Ireland WE 1998 2015 Romania SEE 2007 2015 Slovakia CEE 2005 2015 Slovenia West Balkan 2008 2015 Spain SE 1998 2015 Sweden7) NE 1975 2015 Switzerland WE 1999 2015 United Kingdom WE 1966 2015
WE - West Europe
NE - North Europe
SE - South Europe
SEE - Southeast Europe
CEE - Central & East Europe
First year - first year of data time series in a country/region
Last year - last year of data time series in a country/region
Time series for individual species from national schemes are shorter in certain cases.
1) Data for Belgium were combined from Wallonia and Brussels regions.
2) Data for Cyprus come from two schemes that partly differ in their regional coverage, Volunteer Common Birds Census (2006-2015) and Western Cyprus Common Bird Census (2006-2011). Data from both schemes were combined.
3) Data for France come from two schemes, old (1989-2001) and new one (2001-2014). Data from both schemes were combined but not updated this year.
4) Data for Germany were combined from schemes in former East and West Germany and also newly from old scheme (Häufige Brutvögel alt, 1989-2010) and new scheme (Häufige Brutvögel neu, 2005-2015).
5) Data for Latvia come from three different schemes, two old ones (differ in their regional coverage, and cover the periods 1995-2006 and 2003-2006, respectively) and a new one (2005-2015). Data from all schemes were combined.
6) Data for Norway come from three schemes, Norsk Hekkefugltaksering, HFT (1996-2008), Terrestrisk overvåking, TOV-I (1996-2008) and Terrestrisk overvåking - Ekstensiv, TOV-E (2006-2015). Data from all schemes were combined.
7) Data for Sweden come from two schemes, old (1975-2015) and new one (1998-2015). Data from both schemes were combined.
Although we produce all species indices for the maximum time period (since the first year of time period available), we publish only the European indices since the year 1980 at the earliest since when the index is based on data from several countries - see the latest version of species indices and trends here.
The species trends are produced for the maximum time period and for shorter periods as well: since 1980, 1990, 2000, 2006 and 2011. For simplicity only, we publish the long-term trends (the trends which starting year varies from 1980 to 1998) and the ten-year trends (the trends for last ten years, i.e. 2006-2015).
2.1. Delivery of national data to PECBMS coordination unitCoordinators of national monitoring schemes deliver their national data to the PECBMS coordination unit annually. For information on data and contributing countries see Box Participating countries.
2.2. Combining national data into supranational
2.3. Types of supranational results that PECBMS producesSpecies indices and trends are produced for Europe and its regions (Central & East, North, South, West, and Southeast Europe, East Mediterranean and West Balkan) and for EU and its regions: New (since 2004) and Old EU Members States).