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Summary: Monitoring population changes of 86 land bird species breeding in Finland in 1983–2005

Risto A. Väisänen 2005: Maalinnuston kannanvaihtelut Etelä- ja Pohjois-Suomessa 1983–2005. Linnut-vuosikirja 2005, pp. 83–98.

The report presents the results of the Finnish national monitoring of breeding land birds in 1983–2005. In 2004–2005, a total of 93 censuses were repeated, which consisted of 52 line transects (each 4–6 km long), 35 point count routes (20 points x 5 minutes) and 6 mapping areas. About 20.000 pair observations were made annually in recent years. The data are used to monitor population changes of 86 species in Finland during the last 23 summers. If the data of a species are large enough, population indices are calculated separately for South and North Finland. Trends are analyzed using the TRIM program (model 3, overdispersion and serial correlation are taken into account).

In the 86 species-specific population trend diagrams for the period 1983–2005, there are annual values of the TRIM-index (dot = Finland, triangle pointing downwards = South Finland, triangle pointing upwards = North Finland). Index 1 is the population level at the start year 1983. Figures and symbols within parentheses are the average number of pair observations per year, the trend (average population change in % per year), and the level of statistical significance of the trend (ns = not significant, * = P<0.05, ** = P<0.01, *** = P<0.001, when H 0 is that the average trend is 0%).

Species-specific trends generally resemble those presented in the previous report (Väisänen 2005). The two additional species, the Willow Grouse Lagopus lagopus and the Ruff Philomachus pugnax, have both declined. Conflicting, statistically significant long-term trends between South and North Finland were found in the Willow Warbler Phylloscopus trochilus, Pied Flycatcher Ficedula hypoleuca and Yellowhammer Emberiza citrinella. Annual population fluctuations were often higher in the north than in the south.

Based on the species selection of the European common bird monitoring, bird indicators were calculated for Finland (the last diagram). The decline of farmland birds “Pelto” is apparent in the Finnish data, and also the trends of woodland birds “Metsä” and other common birds “Muut” resemble those found in the Pan-European data.