Use constraints: Data can be used freely given that the source is cited (following creative commons license CC-BY). The source should be cited as: “HELCOM HOLAS 3 Dataset (2023)"

Lineage provided per country:

Estonia: Winter waterfowl censuses have taken place in Estonia since 1960. Today, the midwinter waterbird census is part of the international waterbird census (IWC), which has been in operation since 1967. The midwinter waterbird census has become a collaborative project with volunteers, the Estonian Ornithological Society, the Estonian University of Life Sciences, the University of Tartu and the Environmental Agency. Within the framework of the national environmental monitoring program, annual counts are organized in 119 coastal sectors.

Method: https://kese.envir.ee/kese/viewProgramNew.action?uid=473581

Program description and annual reports: https://keskkonnaagentuur.ee/media/2041/download

Sweden: Spatial data show the sectors used in the Swedish IWC-counts of waterbirds in January. Not much to say about the quality.

Germany 17/06/2022 update:

Data are provided for 1991 to 2021. For the last year data from the eastern part of the German Baltic (Mecklenburg-Western Pommerania) are mostly missing. Data is usually provided by the end of the year following the January count.

Data are from the IWC which are site-based counts from the ground (no aerial surveys included). This means that not all of the 32 species are covered adequately. Gulls were unfortunately not systematically counted in the eastern part of the German Baltic (Mecklenburg-Vorpommern) up to the early years of 2000. Up to 2003 all gull species have thus been set to -1 for these sites. Thereafter gulls were counted more systematically by most observers. Thus trends on these species have to be treated with caution.

Data are provided as raw data as outlined in the guidelines. Please note: If a species didn’t occur at least once at a site, the site is omitted from the dataset (just as TRIM does with such sites). Hence the number of sites varies per species.

Link to metadata of dataset used for indicator calculation: https://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/ed7a9674-af94-49be-8517-4af6a8e1aca0