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No. 148: Migratory bird populations in the Danish bird protection areas, 2004 to 2017

Clausen, P., I.K. Petersen, T. Bregnballe & R.D. Nielsen (2019). Numbers of non-breeding birds in Special Protection Areas for birds in Denmark, 2004 to 2017. Aarhus University, DCE – Danish Centre for Environment and Energy, 308 pp. Technical Report No. 148. http://dce2.au.dk/pub/TR148.pdf (in Danish with English summary)

Summary

In summer 2018, the Danish Environmental Protection Agency requested DCE - Danish Centre for Environment and Energy to prepare a commented database of the occurrence of all migratory waterbird species in the Danish Special Protection Areas (SPAs). This database was specifically to be used to determine which of all the migratory waterbird species roost within each SPA in numbers that justify their inclusion in the SPA designation as qualifying species in a forthcoming revision of these. The report also includes data on a few non-waterbird migratory species listed in Annex 1 of the European Union Birds Directive.

The report is in Danish, but two Appendixes 3 and 4 on pages 304-307 may help an international audience to understand and use the report.

The complete suite of species dealt with, and why they are included, is explained in Chapter 2 and tables therein. Appendix 4 gives an overview of Danish species names used, and their Latin and English equivalents.    

This report describes the results of the migratory waterbird monitoring programme for each of the 113 SPAs as of the beginning of 2018. Particular attention has been paid to the 80 of Denmark's SPAs, where one or more migratory species are already specified in the current SPA designation from 2012, although the 33 other SPAs designated exclusively for their breeding birds are also included in this report. Five of the latter are considered here in more detail because at certain times of the year, larger numbers of waterbirds occur. The remaining 28 are summarised in Appendix 1 of the report. At the end of 2018, an additional new 12 SPAs were designated, one of which (SPA No. 118: Skjern Å) has been treated in more detail together with the adjacent area (SPA No. 43: Ringkøbing Fjord). Another new area which is of particular importance to wintering Greater Scaup (SPA No. 123: Bøjden Nor) is treated with some details, while the remaining 10 new areas are merely summarised in Appendix 1 of the report.

The report provides an overview of the international 1% criteria for flyway populations of waterbird species, which were in effect during 2004-2017. It also presents the basis for, and calculates and presents national 1% criteria for waterbirds as well as for some other Annex 1-species, where these are possible.

The review of all SPAs is presented on the basis of the existing count data available for each site. This is dominated by the results from the National Monitoring and Assessment Programme for the Aquatic and Terrestrial Environment (NOVANA) avian monitoring results from the years 2004-2017, but for some areas this is also extensively supplemented with other data collected by DCE.  These additional data sources include, for example, results from the monitoring of nature reserves and monitoring activities undertaken in relation to the Marine Strategy Framework Directive, which contribute significant data from other years or seasons outside of the NOVANA programme. In some cases, data from the NOVANA avian monitoring programme gathered during 2018 and 2019 are also used, especially in instances where the more recent data are considered to make a significant contribution to data from previous years.

For each of the 85 SPAs considered in detail, the text is supplemented with a boundary map of the SPA and a table showing the current designation criteria based on the occurrence of the key migratory waterbird species present. Next, a review of the specific data available for each SPA is provided, which can vary considerably from locality to locality.

The results of censuses undertaken between 2004 and 2017 are summarized in one or more tables for each SPA and described in the accompanying text.

Special attention in the review has been paid to:

  • species that exceed international and national 1% criteria;
  • aggregations of more than 20,000 waterfowl;
  • periods in the annual cycle when bird species are particularly sensitive (e.g. during flightless wing feather moult and ice winters). 

Most of the data is presented in tabular form. In order to ease interpretation of these tables, those species with numbers exceeding the 1% levels of international importance are shaded light green and those exceeding national levels light blue.

It is important to note that DCE does not consider whether these marked species’ numbers justify designation, since this task lies with the responsible statutory agency (as explained in Appendix 3, A.Box 1 on page 305). Hence, the coloured shading is purely indicative of a species where the abundance on that site has exceeded the 1% population criteria and occurs in greater numbers from an international or national point of view than other species at the site.

In situations where the data show that species formerly included in the SPA designation no longer appear to occur in significant numbers to justify this, extra text is provided to explain these changes and their circumstances.  This may be due, for example, to processes occurring outside of the SPA boundaries, such as the adverse effects of eutrophication on the habitats of individual species or because of global changes in species distribution patterns.

Reproduction is permitted provided the source is explicitly acknowledged, but it is recommended that any use of site or species specific data is made in consultation with the Authors, who can explain shortages in datasets, given that all sites and/or species are not covered equally.