Broedvogels - Atlas of the breeding birds in Flanders 2000-2002

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

Sampling

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.

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 (http://broedvogels.inbo.be), 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.

Method steps

1. For each 5km x 5km square (“atlashok”), volunteers were asked to try and locate as many breeding bird species as possible and to assess both numbers and locations of a selected subset of species. The volunteer could choose how many visits to make and for how long, although it was advised to visit for 30-50 hours and to visit in early morning. This method is indicated in the data as follows: * occurrenceID: contains AH (for “atlashok”) * locationID: code of the “atlashok” * verbatimCoordinates: MRGS code of the “atlashok” * decimalLatitude/longitude: centroid of 5km x 5km “atlashok” * samplingMethod: Bird Census News 2004 1/2 p.36 * samplingEffort: number of observation hours * sampleSize: 25 square kilometer * eventDate: date range for the observation * scientificName: observed species * individualCount: number of breeding pairs for that species * behavior: breeding status
2. In a more standardized method, the volunteer was required to make two one-hour long visits to a set of eight fixed 1km x 1km squares (“kilometerhok”) in each 5km x 5km square: once between April 1 to May 15 and once between May 16 and June 30.
3. In the one-hour visit, the volunteer traversed the 1km x 1km square for 55 minutes and noted all breeding species. This method is indicated in the data as follows: * occurrenceID: contains KM (for “kilometerhok”) * locationID: code of the “atlashok” * verbatimCoordinates: MRGS code of the “kilometerhok” * decimalLatitude/longitude: centroid of 1km x 1km “kilometerhok” * samplingMethod: Bird Census News 2004 1/2 p.36 * samplingEffort: 55 minutes * sampleSize: 1 square kilometer * eventDate: specific date of the observation * scientificName: observed species * individualCount: number of breeding pairs for that species * behavior: no breeding status information
4. In the one-hour visit, the volunteer also did a 5 minute point count near the center of the 1km x 1km square, with a radius of 100m. This method is indicated in the data as follows: * occurrenceID: contains PT (for “punttelling”) * locationID: code of the “atlashok” * verbatimCoordinates: MRGS code of the “kilometerhok” * decimalLatitude/longitude: centroid of 1km x 1km “kilometerhok” * samplingMethod: Bird Census News 2004 1/2 p.36 * samplingEffort: 5 minutes * sampleSize: 1 square kilometer * eventDate: specific date of the observation * scientificName: observed species * individualCount: no information * behavior: no breeding status information
5. The data also includes loose observations. This method is indicated in the data as follows: * occurrenceID: contains LW (for “losse waarneming”) * locationID: code of the “atlashok” * verbatimCoordinates: MRGS code of the “atlashok” * decimalLatitude/longitude: centroid of 5km x 5km “atlashok” * samplingMethod: loose observations * samplingEffort: no information * sampleSize: 25 square kilometer * eventDate: specific date of the observation * scientificName: observed species * individualCount: number of breeding pairs for that species * behavior: breeding status

The dataset covers breeding birds in Flanders, Belgium and includes 193 species. The top 3 recordings are Turdus merula, Columba palumbus, and Troglodytes troglodytes.

1. Animalia
   common name: animals rank: kingdom
2. Chordata
   rank: phylum
3. Aves
   common name: birds rank: class
4. Accipitridae
   common name: hawks, eagles, kites, etc. rank: family
5. Aegithalidae
   common name: bushtits rank: family
6. Alaudidae
   common name: larks rank: family
7. Alcedinidae
   common name: river kingfishers rank: family
8. Anatidae
   common name: ducks, geese & swans rank: family
9. Apodidae
   common name: swifts rank: family
10. Ardeidae
    common name: herons rank: family
11. Caprimulgidae
    common name: nightjars rank: family
12. Certhiidae
    common name: treecreepers rank: family
13. Charadriidae
    common name: plovers, dotterels & lapwings rank: family
14. Ciconiidae
    common name: storks rank: family
15. Cisticolidae
    common name: warblers rank: family
16. Columbidae
    common name: pigeons & doves rank: family
17. Corvidae
    common name: corvids rank: family
18. Cuculidae
    common name: cuckoos rank: family
19. Emberizidae
    common name: buntings rank: family
20. Falconidae
    common name: falcons rank: family
21. Fringillidae
    common name: true finches rank: family
22. Haematopodidae
    common name: oystercatchers rank: family
23. Hirundinidae
    common name: swallows & martins rank: family
24. Laniidae
    common name: shrikes rank: family
25. Laridae
    common name: gulls rank: family
26. Meropidae
    common name: bee-eaters rank: family
27. Motacillidae
    common name: wagtails, longclaws & pipits rank: family
28. Muscicapidae
    common name: Old World flycatchers rank: family
29. Oriolidae
    common name: Old World orioles rank: family
30. Paridae
    common name: tits, chickadees & titmice rank: family
31. Passeridae
    common name: sparrows rank: family
32. Phalacrocoracidae
    common name: cormorants rank: family
33. Phasianidae
    common name: pheasants, partridges, etc. rank: family
34. Picidae
    common name: woodpeckers rank: family
35. Podicipedidae
    common name: grebes rank: family
36. Prunellidae
    common name: accentors rank: family
37. Psittacidae
    common name: parrots rank: family
38. Rallidae
    common name: rails rank: family
39. Recurvirostridae
    common name: avocets & stilts rank: family
40. Regulidae
    common name: kinglets rank: family
41. Remizidae
    common name: penduline tits rank: family
42. Scolopacidae
    common name: sandpipers rank: family
43. Sittidae
    common name: nuthatches rank: family
44. Strigidae
    common name: true owls rank: family
45. Sturnidae
    common name: starlings rank: family
46. Sylviidae
    common name: Old World warblers rank: family
47. Threskiornithidae
    common name: ibises & spoonbills rank: family
48. Troglodytidae
    common name: wrens rank: family
49. Turdidae
    common name: thrushes rank: family
50. Tytonidae
    common name: barn-owls rank: family
51. Upupidae
    common name: hoopoes rank: family

Flanders, Belgium