© Marcel Burkhardt
Publikationen
Schmid, H., M. Burkhardt, V. Keller, P. Knaus, B. Volet & N. Zbinden (2001)
Die Entwicklung der Vogelwelt in der Schweiz/L'évolution de l'avifaune en Suisse.
Further information
Avifauna Report Sempach 1, Annex. 444 S.
Contact
Abstract
Bird communities are not static. The numbers of individuals in a population can
vary greatly from year to year, due to factors such as meteorological conditions
during the breeding season or in the wintering quarters. Long-term changes
become apparent only if populations are monitored closely and continuously. Only
then can a monitoring programme fulfil its role as an early-warning system
providing the basic information necessary for conservation. Monitoring bird
populations is one of the core activities of the Swiss Ornithological Institute
in Sempach. Over the years a large volume of data has accumulated allowing
trends in bird populations to be analysed. The present documentation puts the
emphasis on population trends in time and adds to the Breeding bird atlas
(Schmid et al.1998) and the Avifauna (Winkler 1999a). It allows to show trends
for a wide number of species, but also to identify the gaps in our
knowledge.
Several monitoring programmes have been running for different
groups of species. They are described in the first part of the book.
Observations of rare and scarce breeding birds and visitors are collected in the
database of the "information service". Since 1984 these observations have been
recorded following a set of rules rather than being purely accidental. The
"five-day-period programme" (Pentadenprogramm) and the "breeding bird programme"
(Brutvogelprogramm) have been developed to take variations in observer effort
into account. While the first is particularly suited to present the phenology of
occurrence through-out the year, the second allows to identify trends in number
of sites occupied by breeding birds. The "monitoring programme for common
breeding birds" (Monitoring Häufige Brutvögel) has only been running since 1999.
No results have therefore been included in this volume. However, results are
presented from several smaller programmes such as "breeding birds in wetlands"
(Monitoring Feuchtgebiete), "annual breeding bird reports" (Jahresübersichten),
"continuous survey plots" (Dauerbeobachtungsflächen) or special projects for
particular species. Results are also presented for the waterbird census
(Wasservogelzählungen) in winter.
The main part of the book consists of about
270 species accounts. The amount of data available differs greatly between
species. Overall, waterbirds are the best documented group. In winter, they
occur on the Swiss lakes and rivers in large concentrations. Since the start of
the census in 1967, numbers of most species have increased significantly. Over
the last decade, however, a stabilisation or decline have been observed for
several species. Trends of breeding birds are, in general, not well documented.
Good data sets exist for some raptor species. They indicate mostly stable or
increasing populations. On the other hand, a marked decline has been observed
for many farmland species and for species sensitive to disturbance or to changes
in particular habitat requirements.
Key words: Monitoring, population
trends, Switzerland.