II Atlas of nesting birds - target species (1999-2005)

Study Extent

The geographic area considered for the original study was Mainland Portugal and in the autonomous regions of Madeira and the Azores. The species included are bird species that were observed regarding its nesting activities.

Sampling

The project "Atlas of the Birds that Nest in Portugal" aimed to know the current distribution of breeding species in Mainland Portugal and in the autonomous regions of Madeira and the Azores and to characterise abundance, when possible, of national populations of these species, during the period of 1999 to 2005. Unsystematic and systematic recordings were carried out. For systematic there were 30-minute visits to 6 2x2 km tetrads of a 10x10 km grid. The attribution of the grids were the responsibility of the observer. The data allowed to estimate abundances relative to most species and enable systematic coverage of the territory. Also it directed censuses to know the dimension of the breeding population. These censuses were carried out in areas where the majority of the population was expected to occur. Individuals and/or couples outside these areas, also had the number of breeding individuals and couples recorded. This dataset comprised two layers of information: Directed Census - Distribution data for bird species targeted by directed census, except Aquila adalberti, Aegypius monachus and Pterocles alchata whose location is confidential (includes marginal 10x10 km UTM squares); Other species - distribution data for the remaining species (does not include UTM 10x10 km marginal grids).

Quality Control

Data available was inserted in a specific relational database built specifically for the project, which implemented several quality control methods. In the preparation of the dataset for GBIF publication, data consistency was verified using cluster algorithms using OpenRefine.

Method steps

1. 1. Aggregation of original data from several sources (see above) into a purpose specific relational database built for the project. For details, see Silva (2008). 2. Preparation of the dataset for GBIF publication used as source the geographic layer in shape file format. Although the data layer was a polygon layer with a 10 km grid, the attribute table contained, for the field records, original GPS coordinates with higher precision. In that case, the coordinates with higher spatial precision were considered. The following steps were performed: Conversion of the spatial layer to geographic coordinates using WGS84 as reference system to determine centroids of grid polygons; If the record contained coordinates in the database with higher precision, these were kept; Determination WKT for the polygons for which centroids were considered; Exporting to csv and reinterpretation to attributes to match DwC standard terms.

The Atlas of nesting birds from Portugal collected occurrence data of 29 species, distributed throughout 11 orders and 11 genera.

1. Aquila chrysaetos
   rank: species
2. Aquila fasciata
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3. Ardea cinerea
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4. Ardea purpurea
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5. Bubulcus ibis
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6. Calonectris diomedea
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7. Ciconia ciconia
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8. Ciconia nigra
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9. Egretta garzetta
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10. Falco naumanni
    rank: species
11. Falco peregrinus
    rank: species
12. Gyps fulvus
    rank: species
13. Gyps rueppellii
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14. Ichthyaetus audouinii
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15. Larus michahellis
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16. Milvus milvus
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17. Neophron percnopterus
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18. Nycticorax nycticorax
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19. Oceanodroma castro
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20. Otis tarda
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21. Phalacrocorax aristotelis
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22. Platalea leucorodia
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23. Porphyrio porphyrio
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24. Pterocles orientalis
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25. Pyrrhocorax Pyrrhocorax
    rank: species
26. Recurvirostra avosetta
    rank: species
27. Sterna hirundo
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28. Sternula albifrons
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29. Uria aalge
    rank: species

Mainland Portugal and in the autonomous regions of Madeira and the Azores.