Dutch Centre For Field Ornithology (SOVON) - Breeding Bird Atlas 1998-2000 - metadata
CitationVergeer J, Marx L (2018). Dutch Centre For Field Ornithology (SOVON) - Breeding Bird Atlas 1998-2000 - metadata. Version 1.3. Dutch Centre for Field Ornithology (Sovon). Metadata dataset https://doi.org/10.15468/pqllwv accessed via GBIF.org on 2018-12-16.
DescriptionIn 2002 the Second Atlas of Dutch Breeding birds was published. Fieldwork for the new atlas was carried out during the breeding seasons of 1998, 1999 and 2000, with some additional fieldwork in 2001 to tackle remaining gaps in coverage. A quantitative survey was added in order to allow a more detail-ed analysis of regional differences in abundance.
Study ExtentThe Netherlans, 1998-2000. Many birdwatchers were involved, organised at a regional level by local co-ordinatorsand supervised by a national coordinator and professionalstaff at sovon. Fieldwork was adopted to the national gridof 5-km squares (referred to as atlas squares), which are sub-divided into 25 1-km squares
SamplingContributors to atlas fieldwork were requested to (a) compile a list of breeding bird species for each atlas square; (b) to spend two 1-hour visits in eight 1-km squares; and © to provide an estimate of the number of breeding pairs for a selection of species in an atlas square. The observers were provided with 1:25,000 maps of their atlas squares (indicating the 1-km squares as well) and several observation forms to record their data. The species list was constructed to include a classification of breeding status, i.e. possible, probable or confirmed breeding.Eight out of the 25 1-km squares had to be visited twice during exactly one hour and were selected according to a standard procedure, i.e., observers were not free to choose their own 1-km squares, but had to surveythose assigned by sovon. During the survey, 11,254 1-kmsquares were visited, once between 1 April-15 May and once between 16 May-30 June (with at least two weeks in-be-tween). Visits had to be made in the first hours after sunrise.Generally, this period and this time of the day match theperiod of highest territorial behaviour of Dutch breedingbirds. Observers could either simply record all breeding species present, or (preferably) provide countsof the number of breeding pairs/territories for a selection of species. Moreover, the 1-hourvisit included a point count of five minutes, carried out in the midpoint of the 1-km square and restricted to a 200-m circle around the observer. The surveys of 1-km squares aimed to assess the relative abundance of a species, expressed by the frequency of occurrence.
Quality ControlAll data obtained from atlas fieldwork were collected on standard recording forms. These were sent to the regional coordinators for an extensive check and (in case of questionable records) inquiry among the observers. Record sheets were then entered in a data-base (by double data-entry, to eliminate typing errors) and finally checked by regional specialists to detect unusual observations. In addition, a model based on a national database with habitat characteristics per atlas square was developed to detect outliers and atlas squares with insufficient coverage. This analysis,carried out with data received in 1998-2000, initially revealed 92 atlas squares with poor coverage (mainly an incomplete species list). After additional fieldwork had been organised in 2001, only 36 atlas squares remained for which coverage was considered as insufficient.
- 1. Fieldwork, carried out in 5x5 km squares 2. Data-entry and extensive checks on the accuracy of the information 3. Presentation and interpretation of the data
Additional infoBackgrounds and aims The first breeding bird atlas of The Netherlands, published in 1979 and for which fieldwork was conducted in 1973-77(TEIXEIRA 1979), was a milestone in Dutch ornithology. It was not only the first time that the distribution of all breeding bird species was mapped at a national level, but it also stimulated a large number of volunteer birdwatchers to take part in follow-up projects like the year-round atlas in 1978-83(Atlas van de Nederlandse Vogels; sovon1987) or become involved in long-term monitoring projects such as the Broedvogel Monitoring Project(bmp; common breeding birdcensus). These projects were among the first national ornithological surveys organised by SOVON Vogelonderzoek Nederland(Dutch Centre for Field Ornithology), initially established as a foundation in 1973to stimulate volunteer fieldornithology, but today coordinator for national ornithological monitoring projects.Following the second generation of breeding bird atlases published in several neighbouring countries (e.g., United Kingdom and Ireland, France, Denmark, Switzerland, Fin-land), ideas for a second Dutch breeding bird atlas evolved by the end of the 1990s. A new atlas would assess many changes in the distribution of breeding birds at a national level, of which some had already been pointed at by the monitoring schemes and the recently published volumes ofthe Dutch Avifauna (VAN DEN BERG & BOSMAN 2001, BIJLSMA ET AL.2001). The main aims of the atlas were therefore to assess the current distribution of breeding birds in The Netherlands,and to review changes in distribution between the first atlas in the 1970s and the new atlas in the 1990s. Moreover, data on current distributions at a national level were considered invaluable for evaluation of results obtained by monitoring schemes like the bmp. Additionally, it was assumed that anew atlas would encourage many new observers to becomeinvolved in volunteer survey work. Fieldwork was organised in such a way that less-experienced ornithologists were able to take part in the project. Unlike the first atlas, a quantitative survey (according to a slightly modified model from the British atlas) was added in order to allow a more detail-ed analysis of regional differences in abundance. As this part of the fieldwork was highly standardized, it provides a baseline data set for future atlas projects.
Breeding birds of The Netherlands
Aviscommon name: Vogels rank: class
Sovon Dutch Centre for Field Ornithology
NL - 6525 ED
administrative point of contact
Sovon Dutch Centre for Field Ornithology
NL - 6525 ED