Dataset of long-term bird monitoring in Qigu wetlands, Taiwan

Study Extent

Six representative sites within southwestern Qigu District were selected as the sampling sites of this monitoring project (as shown in column “locality” of the DwC Occurrence Extension), including Lighthouse Fish Farms (LHF), North Fish Farms (NFF), East Fish Farms (EFF), Qigu Levee (QGL), American Fish Farm Ruins (AFR) and American Fish Farms (AFF). Bird censuses were conducted once a month at these six sampling sites from April 2015 to March 2021. The main habitat type within these sampling sites are fish farms for clams (Meretrix lusoria) or milkfish (Chanos chanos), while the habitat environment still slightly differs between sites. The centroid coordinates (WGS84) of 6 sampling sites: LHF: 23.09003°N, 120.04050°E; NFF: 23.08897°N, 120.05879°E; EFF: 23.08006°N, 120.06647°E; QGL: 23.07881°N, 120.08044°E; AFR: 23.09383°N, 120.08439°E; AFF: 23.09788°N, 120.08256°E

Sampling

The monthly bird censuses at LHF, NFF, EFF and QGL were conducted using transect method (as shown in column “samplingProtocol” of the DwC Event Core). These transects are usually trails beside fish farms (at LHF, NFF, EFF) or along the levee (at QGL), with the length ranging from 0.826 km to 3.129 km. In contrast, monthly censuses at AFR and AFF were conducted using counting flocks method, which means counting flocks of birds within a predefined area. The sampling areas of AFR and AFF are 9.8 ha and 22.4 ha, respectively. Bird censuses were all conducted during daytime (mostly between 9 a.m. and 5 p.m.), with no strict limitation on the starting time and duration of each census.

Quality Control

All of the monthly bird censuses were carried out by 1-3 experienced and well-trained bird observers. To keep the quality steady, only 5 observers (including 2 main observers and 3 occasionally assistant observers) have been involved during the time coverage of this dataset (April 2015 to March 2021). All of the occurrence records were integrated and examined after each census. Any uncommon or abnormal records will be confirmed, and modifications will be made if necessary. The taxonomy information in this dataset is organized based on the eBird Taxonomy v2022 (Clements et al. 2022) and the 2023 TWBF Checklist of the Birds of Taiwan (Ding et al. 2023).

Method steps

1. All of the six sampling sites and the corresponding census methods were determined at the beginning of this project. For the transect censuses (at LHF, NFF, EFF and QGL), a team of observers walked along a predefined transect and recorded the birds nearby. For the counting flocks censuses (at AFR and AFF), observers counted and recorded the birds within a predefined area, which is typically composed of several fish farms. Observers used binoculars (typically 10x42) and/or monoculars (20-60x) to detect and observe birds in all censuses, and recorded bird species as well as the number of individuals. Birds seen or heard by the observers were all recorded, except for those birds only flying through sampling area without perching or foraging behaviors. The weather condition determined by visual observation was also recorded for each census (presented as a categorical variable in the DwC Measurement or Facts Extension). Each monthly census at each of the six sampling sites is regarded as a sampling event (as shown in column “eventID” of the DwC Event Core). It should be noted that from April 2015 to around June 2018, all of the bird occurrences within a single sampling event were recorded at the same coordinate, which is the centroid coordinate of the sampling site. However, the bird occurrences were recorded at the coordinate of several distinct locations, which correspond to different sections along the transect or different districts within the site, since around June 2018 (the time points slightly differ between sampling sites). The change of recording protocol can be observed through columns “locationID”, “decimalLatitude” and “decimalLongitude” of the DwC Occurrence Extension.

A total of 120 bird species, spanning 36 families and 16 orders, are included in this dataset. The most dominant family (the family with the most individuals recorded) is Ardeidae (27,654), followed by Scolopacidae (15,777), Anatidae (12,074), Recurvirostridae (9,617) and Charadriidae (8,326). The Family with the most species recorded is Scolopacidae (25 species), followed by Ardeidae (11 species), Charadriidae (8 species), Anatidae (7 species) and Laridae (7 species). The most dominant species is little egret (Egretta garzetta), followed by great egret (Ardea alba), black-winged stilt (Himantopus himantopus), Kentish plover (Charadrius alexandrinus) and Eurasian tree sparrow (Passer montanus).

1. Aves
   common name: Bird rank: class
2. Charadriiformes
   rank: order
3. Pelecaniformes
   rank: order
4. Passeriformes
   rank: order
5. Anseriformes
   rank: order
6. Columbiformes
   rank: order
7. Podicipediformes
   rank: order
8. Gruiformes
   rank: order
9. Accipitriformes
   rank: order
10. Galliformes
    rank: order
11. Coraciiformes
    rank: order
12. Falconiformes
    rank: order
13. Cuculiformes
    rank: order
14. Piciformes
    rank: order
15. Suliformes
    rank: order
16. Bucerotiformes
    rank: order
17. Psittaciformes
    rank: order

The dataset includes sampling events in the southwestern part of Qigu District (in Tainan City), which is located on the southwest coast of Taiwan main island.