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Trends of common birds in Europe, 2009 update
This report presents an enlarged set of population trends and indices of 136 common bird species in Europe which have been produced by the Pan-European Common Bird Monitoring Scheme (PECBMS) in 2009. The trends and indices presented in this report cover time period 1980 - 2007, although data back to 60s are available from some European countries. Updated indicators for Europe and its regions based on data till 2007 are published on the EBCC website as well (see the special report).
Acknowledgements
Special thanks to the data providers & organisations responsible for national data collection and analysis: Norbert Teufelbauer, Christian Vansteenwegen, Anne Weiserbs, Jean-Paul Jacob, Anny Anselin, Thierry Kinet, Anotoine Derouaux, Svetoslav Spasov, Zdeněk Vermouzek, Josef Chytil, Jiří Reif, Henning Heldbjerg, Michael Grell, Anne Eskildsen, Andres Kuresoo, Jaanus Elts, Risto A. Väisänen, Fréderic Jiguet, Johannes Schwarz, Martin Flade, Tibor Szep, Olivia Crowe, Dick Coombes, Lorenzo Fornasari, Elisabetta de Carli, Ainars Aunins, Ruud P.B. Foppen, Magne Husby, Przemek Chylarecki, Barbara Archita, Ricardo Martins, Ana Meirinho, Geoff Hilton, Jozef Ridzoň, Katarína Slabeyová, Juan Carlos del Moral, Virginia Escandell, Åke Lindström, Sören Svensson, Hans Schmid, David G. Noble, Kate Risely, Andrew Joys. The national data providers helped not only with data provision but also with many valuable comments.
Arco Van Strien and Adriaan Gmelig Meyling contributed with final data analysis and computation procedure. Tomáą Telenský helped very much with this web presentation.
We thank to Richard Gregory, Ian Burfield, Lukáą Viktora, Norbert Schaffer, David W. Gibbons, Jose Tavares, Sergi Herrando, Dominique Richard and Anne Teller for valuable comments and help with data collation, analysis and for general support.
Thanks to the many thousands of skilled volunteer counters responsible for data collection.
Since its beginning in 2001, the PECBMS project has been supported by the Royal Society for Protection of Birds (RSPB, the BirdLife International Partner in the UK). Since January 2006 the project has been funded by the European Commission as well. Sole responsibility lies with the authors and the European Commission is not responsible for any use that may be made of the information contained in this document.
Other important partners of the project are: European Bird Census Council (EBCC), BirdLife International, Statistics Netherlands, Czech Society for Ornithology (CSO, BirdLife International Partner in the Czech Republic), British Trust for Ornithology (BTO), Dutch Organisation for Field Ornithology (SOVON), and others.
Data
National monitoring schemes coordinators usually provide data on more than 200 species, however, data on many species are poor that European index cannot be produced. Finally, reliable European index was produced on 136 species including one new species (Sylvia hortensis) in 2009. Number of countries contributing with the data has also increased of one country compared to the last year: Slovakia has provided the national indices since 2005 for the first time. Moreover, Netherlands provided data over the larger time period (1984 - 2007) this time.
The 22 countries providing the data for 2009 update are: Austria, Belgium, Bulgaria, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Ireland, Italy, Latvia, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland, United Kingdom.
The countries provided the data for different time periods (see the special report or check the ´List of countries´ at the individual species graphs).
Methods
At first, individual national species indices are produced by annually operated national breeding bird surveys from 22 European countries that cover different periods and are obtained through the PECBMS. These national species indices are computed using a software package named TRIM which allows for missing counts in the time series and yields unbiased yearly indices and standard errors using Poisson regression. The next step is the hierarchical combination of national indices into supranational ones (regional or European indices). This combination is also computed in the TRIM and in doing so, the national indices are weighted by estimates of national species population sizes (derived from Birds in Europe 2 (BirdLife International 2004)). Weighting is used because different countries hold different proportions of each species´ European population. Although national schemes differ in field methods, these differences do not influence the supranational results because the indices are standardised before being combined. More detailed information on computation methods and data quality control is summarized in special report (see).
The computation methods are also described in papers from van Strien et al. (2001) and Gregory et al. (2005).
Species habitat classification for main habitat types (farmland, forest and other) have been developed using improved procedure accepted at the PEBCMS workshop in Prague in 2005. This procedure is based on species classification within four main biogeographical regions: Atlantic, Boreal, Continental and Mediterranean. Species habitat classification has not undergone any changes since last year, details on species classification procedure can be found here.
Results
Updated European species indices, long-/short-term trends and slopes, and species habitat classification are summarised in the table (for explanations to the table see ´Legend´ below the table).
For showing the graph of species´ index, click on species name in the table. For drawing and comparing graphs for several species at once, tick a check box at left side of a species name and click on a button ´Show graphs for selected species´ below the table to confirm and proceed your selection. You can also draw graphs for all species at once (´Select all´) or quickly deselect your choice (´Reset´). The list of countries and time periods for they provided the data for each species can be found at individual species graphs (´List of countries´).
Despite the data quality control, quality of outputs might differ species by species. Furthermore, year to year fluctuations might not always reflect real population change. Therefore we recommend cautious interpretation of year by year changes and readers should also pay attention to species legend. For any use of the results presented in this report, we strongly recommend to consult PECBMS coordination unit (EuroMonitoring (at) birdlife.cz) .
Legend:
1) Data for Long-term Trend and Long-term Slope not available.
2) Data for Long-term Trend and Long-term Slope available over the period 1982-2007.
3) Data for Long-term Trend and Long-term Slope available over the period 1984-2007.
4) Data for Short-term Trend and Short-term Slope available over the period 1991-2007.
5) Data for Short-term Trend and Short-term Slope available over the period 1996-2007.
6) Data for Short-term Trend and Short-term Slope available over the period 1999-2007.
7) Data for Short-term Trend and Short-term Slope available over the period 2005-2007.
a) Trend - change (in %) in an index value between the first and the last year of a time period (Long-term Trend - over the period 1980-2007, Short-term Trend - over the period 1990-2007).
b) Slope - multiplicative trend over a time period considered, reflects average percentage change per year. If the slope value is 1, there is no trend. If > 1, there is a positive trend, if < 1, trend is negative. For instance, 1.08 means 8 % increase per year, 0.93 means 7 % decline per year. Slope standard error (SE) in parenthesis (Long-term Slope - over the period 1980-2007, Short-term Slope - over the period 1990-2007).
c) Habitat
for - forest
farm - farmland
oth - other
References:
Van Strien, A.J. Pannekoek, J. & Gibbons, D.W. 2001. Bird Study 48: 200-213.
BirdLife International 2004. Birds in Europe: population estimates, trends and conservation status. Cambridge, UK: BirdLife International. (BirdLife Conservation Series No. 12).
Gregory, R.D., van Strien, A.J., Vorisek, P., Gmelig Meyling, A.W., Noble, D.G., Foppen, R.P.B. & Gibbons, D.W. 2005. Phil. Trans. R. Soc. Lond. B 360: 269-288.