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)"

Following the HOLAS 3 data call, breeding bird data of 30 species for the years 1991-2021 were supplied by authorities from Contracting Parties of HELCOM, except Russia and Lithuania.

Spatial data was provided as points, lines and polygons. Further data in excel format was also provided.

Link to core indicator metadata: https://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/7aaf9c75-7c26-465c-989f-494fbebf1c7d

National remarks

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.

For offshore data, bird data from aerial surveys carried out in winter 2019/2020 and 2021/2021, respectively.

Data/file structure and codes according to the most recent version of the ESAS model ( https://esas-docs.ices.dk/tables/).

Exceptions:

Campaign_id added to table file information

Table samples, field platformcode.

The airplane’s registration number is entered instead of the code ZZ91.

Table observations, field observationdistance

Letters G, J, K, R are used instead of numeric values.

Table position

Transect ID and track_azimuth are added

Nb. Campaign 5373-1-1 and 5373-9-2 show spatial overlap.

Spatial data show 1). Tracks (swe-track_2019-2020_3035, point) and 2) line transects (SurveyedLines_3035 ) used during the surveys.

Germany:

• 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.

National data provider:

Dachverband Deutscher Avifaunisten e.V. (DDA)

Estonian University of Life Sciences

Lund university

Museum and Institute of Zoology PAS / OTOP BirdLife Poland

Luonnontieteellinen keskusmuseo, LUOMUS - Finnish Museum of Natural History