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Broedvogels - Atlas of the breeding birds in Flanders 2000-2002
Vermeersch G, Anselin A, Devos K, Herremans M, Stevens J, Gabriëls J, Van Der Krieken B, Brosens D, Desmet P (2021): Broedvogels - Atlas of the breeding birds in Flanders 2000-2002. v1.6. Research Institute for Nature and Forest (INBO). Dataset/Occurrence.

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Availability: CC0 To the extent possible under law, the person who associated CC0 with this dataset has waived all copyright and related or neighboring rights to this dataset.

Notes: To allow anyone to use this dataset, we have released the data to the public domain under a Creative Commons Zero waiver. We would appreciate however, if you read and follow these norms for data use and provide a link to the original dataset whenever possible. If you use these data for a scientific paper, please cite the dataset following the applicable citation norms and/or consider us for co-authorship. We are always interested to know how you have used or visualized the data, or to provide more information, so please contact us via the contact information provided in the metadata, or

Broedvogels - Atlas of the breeding birds in Flanders 2000-2002 is a species occurrence dataset published by the Research Institute for Nature and Forest (INBO). The dataset contains more than 330,000 bird observations, collected during three breeding seasons (2000, 2001, 2002) using a standardized field methodology using a 5km x 5km square grid system covering all of Flanders, Belgium (645 squares) as well as up to eight 1km x 1km sample squares within each larger square. Test data from 1999 and additional data to increase coverage from 2003 are also included. The dataset includes information on 197 taxa, of which 183 species (13 exotic) and 3 subspecies are considered breeding in Flanders. The data are released in bulk as open data. more

Taxonomic coverage: The dataset covers breeding birds in Flanders, Belgium and includes 193 species. The top 3 recordings are Turdus merula, Columba palumbus, and Troglodytes troglodytes.
Sampling methods: In each 5km x 5km square, volunteers were initially asked to try and locate as many breeding bird species as possible and to assess both numbers and locations of a selected sub-set of species. In doing so, they were free to choose the time and duration of their observations, although a few general guidelines were provided. Subsequently, as part of a standardized fieldwork procedure, they were required to make two one-hour long visits to sets of eight fixed 1km x 1km squares. Each volunteer was provided with a 1:10.000 scale map of each 5km x 5km square on which the 1km x 1km squares were also indicated and several forms were issued to record their data. As with the Dutch method, the species list was constructed to include a classification of breeding status, i.e. possible, probable or confirmed breeding. The aim of the hour long counts was to construct relative abundance maps and during each hour a 5 minute point count was performed in the middle of every square. These short duration point counts fine-tuned these maps in the case of common species, which were often recorded during the hour count, irrespective of their relative abundance. During the hour counts, observers were asked to record all breeding bird species present and to provide counts of the number of breeding pairs/territories for a selection of species. The sampling method is described in more detail in Bird Census News 2004 1/2: 35-47.
Study extent: During the 1999 breeding season, an inventory of several atlas squares was produced as a test. The method used in that first season replicated the one used in the Dutch atlas project (Sovon 2002) and was also based on the Universal Transverse Mercator (UTM) projection to divide Flanders into an internationally recognized grid of 5km x 5km squares. Fieldwork was organized in such a way that less-experienced ornithologists were able to take part in the project. It was carried out during the breeding seasons of 2000, 2001 and 2002. In 2003, a few additional squares were surveyed in order to increase coverage. Many birdwatchers were involved, organized at a local level by regional coordinators and overseen by a national coordinator and professional INBO staff. The largest volunteer organization in Flanders, Natuurpunt, was primarily involved in organizing the volunteer structure. In general, fieldwork consisted of surveys on both 5km x 5km and 1km x 1km scales and a total of 645 squares had to be surveyed. The main aims of the atlas were as follows: * to assess the current distribution of all breeding bird species in Flanders * to assess their relative abundance where possible * to create detailed population estimates for around 65 % of all species * to gather exact location data for all rare, colonial and exotic breeding bird species throughout Flanders.
Quality control: All data obtained from atlas fieldwork were collected on standard recording forms. These were sent to the regional coordinator who checked them thoroughly and contacted volunteers in case of any obvious anomalies. Following this first step, data were sent to the INBO where they were checked once more before being entered in an SQL-database. Forms were printed from the database which were returned to the individual volunteers. They were asked to check the lists one final time in order to ensure accuracy. After the final breeding season, the completed lists for each region were sent to the relevant coordinators asking them to provide extra information on the annual numbers of some colonial or rare breeding bird species per square. For some pioneer species like Sand Martin and Avocet or obvious species like Rook, we wanted to be able to estimate the numbers in each of the three atlas years. Technology also presented a convenient way of double-checking data. By posting preliminary versions of species maps (distribution, numbers and relative abundance) on a frequently updated website (, volunteers were able to easily provide many useful comments. The site also provided the opportunity to submit records from outside the census procedures, resulting in over 60.000 extra observations. These observations were also submitted to regional coordinators for them to assess credibility and accuracy. Afterwards, if the observations enhanced the information per square, they were incorporated, although they could be traced at all times.
Purpose: The first atlas of breeding birds in Flanders was published in 1988 and was based on fieldwork conducted between 1973-1977 (Devillers et al. 1988). For almost three decades, this work provided the only information available on the distribution and abundance of all breeding bird species in Flanders. Although several species-specific projects were subsequently undertaken, it was not until 1994 that a monitoring programme for rare, colonial and exotic bird species was initiated. This was coordinated by the then Institute of Nature Conservation (IN), now the Research Institute for Nature and Forest (INBO), a research institute of the Flemish Government. Although this project provided very useful information that could be used for defining special protection areas (SPAs), it was clear that the rest of the breeding avifauna, including common species, was experiencing major changes. As a direct response, during 1998, a new comprehensive breeding atlas project was launched by the INBO in collaboration with several other organizations and financed by the Flemish Government.
Issues with the dataset can be reported here.
The publication of this dataset was supported by the INBO as part of the Flemish contribution to LifeWatch.

Biology > Birds
Terrestrial, Breeding seasons, Distribution, Observation, Belgium, Flanders, Aves

Geographical coverage
Belgium, Flanders [Marine Regions]

Temporal coverage
4 April 1999 - 27 June 2003

Taxonomic coverage
Aves [WoRMS]

Occurrence of biota

Vlaamse overheid; Beleidsdomein Omgeving; Instituut voor Natuur- en Bosonderzoek (INBO), moredata creator
Limburgse Koepel voor Natuurstudie, Vogelwerkgroep, moredata creator
Natuurpunt, moredata creator

LifeWatch: Flemish contribution to, more

Based on this dataset
Vermeersch, G. et al. (2004). Atlas van de Vlaamse broedvogels 2000-2002. Mededelingen van het Instituut voor Natuurbehoud, 23. Instituut voor Natuurbehoud, Ministerie van de Vlaamse Gemeenschap Afdeling Natuur en Natuurpunt vzw: Brussel. ISBN 90-403-0215-4. 495 pp., more

Dataset status: Completed
Data type: Data
Data origin: Data collection
Metadatarecord created: 2017-06-26
Information last updated: 2021-07-07
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