Biodiversity Data Journal : Data Paper (Biosciences)
Data Paper (Biosciences)
Occurrence dataset of waterbirds in the Tiaozini Wetland, a World Nature Heritage, China
expand article infoWei Hu, Taiyu Chen, Zheping Xu§, Dawei Wu, Changhu Lu
‡ College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
§ National Science Library, Chinese Academy of Sciences, Beijing, China
Open Access



Tiaozini, the core area of the Yellow (Bohai) Sea Migratory Bird Habitat in Dongtai, Jiangsu Province and a World Heritage Site, has provided an ideal habitat for migratory birds. As an important hub on the East Asian–Australasian Flyway (EAAF), Tiaozini Wetland provides pivotal stopover and wintering sites for tens of thousands of migratory waterbirds, including some global critically endangered species, such as Spoon-billed Sandpiper (Calidris pygmaea) and Spotted Greenshank (Tringa guttifer). Although many researchers have conducted a lot of studies on waterbirds in Tiaozini Wetland, there is still a lack of a dataset on waterbird species composition and individual quantity in Tiaozini Wetland throughout the year. Here, we conducted a one-year waterbird survey in the Tiaozini Wetland during 2020-2021 and provided an occurrence dataset with detailed species and geographic information.

New information

This occurrence dataset is the first public record of species and number of waterbirds in Tiaozini Wetland for a whole year, which includes the taxonomic information, location information, number, investigation date and endangered level for each species. All data have been published on GBIF.


Tiaozini Wetland, World Nature Heritage, waterbirds, endangered species, dataset


The East Asian–Australasian Flyway (EAAF) is one of the nine major migratory bird migration routes in the world, with a total length of about 12,000 kilometres, spanning 22 countries and nearly 50 million waterbirds migrating on this route, which is the most crowded and also the most threatened migratory route for migratory birds (Chen 2015). As the centre of the EAAF, China's coastal wetlands provide habitats for more than 200 migratory waterbirds species and over 70% of the globally-threatened waterbirds species on the EAAF depend on China's Yellow and Bohai Seas intertidal wetlands (Xia et al. 2017). However, in the past 50 years, due to the substantial increase in land demand caused by population growth and economic development, about 40% of China's coastal wetlands have been degraded or disappeared (Xia et al. 2017). Coastal wetlands reclamation, environmental pollution and biological invasion have caused the loss and fragmentation of waterbirds' habitats, which have seriously threatened the survival of waterbirds on EAAF (Peng et al. 2017).

The Tiaozini Wetland is located in Dongtai, Jiangsu Province, China, which is an important stopover and wintering habitat for migratory waterbirds on the EAAF (Tong et al. 2012, Gao et al. 2021). Amongst the waterbirds inhabiting in the Tiaozini Wetland, 21 species accounted for more than 1% of the total species on the EAAF (Bai et al. 2015). At the same time, about 40% of the world's Spoon-billed Sandpiper population moult in the Tiaozini Wetland and the number of Spotted Greenshank recorded in the Tiaozini Wetland is twice the estimated world population of this species in 2016 (Bai et al. 2015, Chang et al. 2019). Therefore, the Tiaozini Wetland is not only a pivotal area for endangered species protection, but also a hotspot for waterbirds observation and waterbirds research. Considering the importance of the Tiaozini Wetland for migrating waterbirds on the EAAF, on 5 July 2019, the first phase of the China Yellow and Bohai Seas Migratory Bird Habitat, which is located in the Tiaozini Wetland, was listed as a World Natural Heritage Site by UNESCO and it was also the first intertidal Wetland Heritage Site in China and the second in the world (IUCN 2019, Wang et al. 2021). Therefore, many bird researchers have carried out various studies in the Tiaozini Wetland. Clark et al. (2016) first accurately estimated the global population of Spoon-billed Sandpiper by surveys in Tiaozini, Yangkou and Dongling in 2014 (Clark et al. 2016); Gao et al. (2021) investigated the diversity index of waterbird communities in the Tiaozini and Rudong Wetlands during the overwintering period from 2017 to 2020 (Gao et al. 2021); Sun et al. (2021) studied the habitat selection of waterbirds in coastal wetlands for the impact of reclamation on migratory waterbirds during the overwintering period from 2018 to 2019 in Jiangsu Province (Sun et al. 2021). In addition, many researchers used published data to study habitat suitability, network structure and function in the Tiaozini Wetland (Duan et al. 2020, Wang et al. 2022). However, most studies only recorded and published waterbirds data on part of the species and some months. The annual list of waterbirds in the Tiaozini Wetland was not published, so we investigated the species composition and waterbirds quantities in the Tiaozini Wetland throughout the year and provided occurrence data in order to support waterbird diversity research and endangered species protection in the future.

Sampling methods

Sampling description: 

We used the sampling points method to investigate species composition and individual quantity of waterbirds in Tiaozini Wetland. After the pre-survey fieldwork, we set up 55 observation points with an interval of about 1 km (Fig. 1). The waterfowl survey was conducted on a monthly basis during good weather conditions, within a 2 h time window before and after high tide according to the local tidal table. The time spent at each observation site was approximately 4 minutes and the observation area was a circle area with a 500 m radius centred on the observation site. The species and quantity of waterbirds in the field of view were counted using Shuntu 8 x 42 binoculars and Nikon 10 x 60 monoculars and waterbirds were photographed and recorded using a Canon 6D2 camera with external 150-600 mm lens. To save time and avoid duplicate counts, three groups of experienced researchers (two in each group) conducted surveys simultaneously in different areas of the Tiaozini Wetland. Only waterbirds staying or flying into the observation area were recorded, while waterbirds flying out of the observation area were not recorded. For bird groups that were easy to identify and small in number, the species and quantity of birds were recorded directly using the count method; for bird groups that were difficult to identify and large in number, the quantity of waterbird clusters and the proportion of each species were estimated using the photo-taking method, followed by identification. Classification of waterbirds was undertaken according to A Checklist on the Classification and Distribution of the Birds of China (Third Edition) (Zheng 2017). Collation and summary of waterbirds data were carried out after the daylight fieldwork by using Microsoft Office Excel 2021 and the data setwas organised according to the Darwin Core format and uploaded to GBIF after the one-year survey (Hu et al. 2022).

Figure 1.  

Location of observation sites and study area.

Geographic coverage


We downloaded the Landsat8 satellite image on 18 September 2020 and drew the investigation scope by using ArcGIS 10.7 software. Our survey covered almost all areas of Tiaozini Wetland, such as estuary, intertidal, aquaculture pond and farmland.


32.71N and 32.89N Latitude; 120.89E and 120.97 E Longitude.

Taxonomic coverage


A total of 51231 waterbirds were recorded in this occurrence dataset, belonging to 104 species, 16 families and nine orders (Table 1). Many species were included in the China Species Red List and the IUCN Red List (Wang and Xie 2009, IUCN 2021). In the China Species Red List, Calidris pygmaea (Linnaeus, 1758), Tringa guttifer (Nordmann, 1835), Saundersilarus saundersi (Swinhoe, 1871), Ciconia boyciana (Swinhoe, 1873), Platalea minor (Temminck & Schlegel, 1849) and Pelecanus crispus (Bruch, 1832) were ranked as National First-class Protected Animals; Anser albifrons (Scopoli, 1769), Cygnus columbianus (Ord, 1815), Aix galericulata (Linnaeus, 1758), Mergellus albellus (Linnaeus, 1758), Podiceps nigricollis (Brehm, 1831), Limnodromus semipalmatus (Blyth, 1848), Numenius minutus (Gould, 1841), Numenius arquata (Linnaeus, 1758), Numenius madagascariensis (Linnaeus, 1766), Arenaria interpres (Linnaeus, 1758), Calidris tenuirostris (Horsfield, 1821), Calidris falcinellus (Pontoppidan, 1763) and Platalea leucorodia (Linnaeus, 1758) were ranked as National Second-class Protected Animals. In the IUCN Red List, Calidris pygmaea (Linnaeus, 1758) was ranked as Critically Endangered (CR); Numenius madagascariensis (Linnaeus, 1766), Tringa guttifer (Nordmann, 1835), Calidris tenuirostris (Horsfield, 1821), Ciconia boyciana (Swinhoe, 1873) and Platalea minor (Temminck & Schlegel, 1849) were ranked as Endangered (EN); Aythya ferina (Linnaeus, 1758) and Saundersilarus saundersi (Swinhoe, 1871) were ranked as Vulnerable (VU); Mareca falcata (Georgi, 1775), Aythya nyroca (Güldenstädt, 1770), Haematopus ostralegus (Linnaeus, 1758), Vanellus vanellus (Linnaeus, 1758), Limnodromus semipalmatus (Blyth, 1848), Limosa limosa (Linnaeus, 1758), Limosa lapponica (Linnaeus, 1758), Numenius arquata (Linnaeus, 1758), Tringa brevipes (Vieillot, 1816), Calidris canutus (Linnaeus, 1758), Calidris ruficollis (Pallas, 1776), Calidris ferruginea (Pontoppidan, 1763) and Pelecanus crispus (Bruch, 1832) were ranked as Near Threatened (NT). The reason for the rank differences of some waterbird species between the China Species Red List and IUCN Red List is due to the large difference between the distribution quantity of these species in the world and China.

Table 1.

Waterbirds list in the Tiaozini Wetland.

Rank Order Family Scientific name Number of observations
1 Anseriformes Anatidae Anser fabalis 70
2 Anseriformes Anatidae Anser albifrons 1
3 Anseriformes Anatidae Cygnus columbianus 5
4 Anseriformes Anatidae Tadorna tadorna 358
5 Anseriformes Anatidae Tadorna ferruginea 38
6 Anseriformes Anatidae Aix galericulata 2
7 Anseriformes Anatidae Mareca strepera 98
8 Anseriformes Anatidae Mareca falcata 354
9 Anseriformes Anatidae Mareca penelope 47
10 Anseriformes Anatidae Anas platyrhynchos 426
11 Anseriformes Anatidae Anas zonorhyncha 2097
12 Anseriformes Anatidae Anas acuta 23
13 Anseriformes Anatidae Anas crecca 1475
14 Anseriformes Anatidae Spatula clypeata 135
15 Anseriformes Anatidae Spatula querquedula 25
16 Anseriformes Anatidae Aythya ferina 861
17 Anseriformes Anatidae Aythya nyroca 4
18 Anseriformes Anatidae Aythya fuligula 502
19 Anseriformes Anatidae Aythya marila 16
20 Anseriformes Anatidae Mergellus albellus 2
21 Anseriformes Anatidae Mergus merganser 30
22 Podicipediformes Podicipedidae Tachybaptus ruficollis 285
23 Podicipediformes Podicipedidae Podiceps cristatus 36
24 Podicipediformes Podicipedidae Podiceps nigricollis 7
25 Phoenicopteriformes Phoenicopteridae Phoenicopterus roseus 14
26 Gruiformes Rallidae Gallinula chloropus 152
27 Gruiformes Rallidae Fulica atra 10188
28 Charadriiformes Haematopodidae Haematopus ostralegus 263
29 Charadriiformes Recurvirostridae Himantopus himantopus 374
30 Charadriiformes Recurvirostridae Recurvirostra avosetta 4175
31 Charadriiformes Charadriidae Vanellus vanellus 45
32 Charadriiformes Charadriidae Vanellus cinereus 73
33 Charadriiformes Charadriidae Pluvialis fulva 109
34 Charadriiformes Charadriidae Pluvialis squatarola 814
35 Charadriiformes Charadriidae Charadrius dubius 98
36 Charadriiformes Charadriidae Charadrius alexandrinus 1438
37 Charadriiformes Charadriidae Charadrius mongolus 288
38 Charadriiformes Charadriidae Charadrius leschenaultii 795
39 Charadriiformes Scolopacidae Scolopax rusticola 2
40 Charadriiformes Scolopacidae Gallinago gallinago 13
41 Charadriiformes Scolopacidae Limnodromus scolopaceus 2
42 Charadriiformes Scolopacidae Limnodromus semipalmatus 38
43 Charadriiformes Scolopacidae Limosa limosa 1360
44 Charadriiformes Scolopacidae Limosa lapponica 1214
45 Charadriiformes Scolopacidae Numenius minutus 3
46 Charadriiformes Scolopacidae Numenius phaeopus 84
47 Charadriiformes Scolopacidae Numenius arquata 1563
48 Charadriiformes Scolopacidae Numenius madagascariensis 52
49 Charadriiformes Scolopacidae Tringa erythropus 149
50 Charadriiformes Scolopacidae Tringa totanus 378
51 Charadriiformes Scolopacidae Tringa stagnatilis 158
52 Charadriiformes Scolopacidae Tringa nebularia 546
53 Charadriiformes Scolopacidae Tringa guttifer 65
54 Charadriiformes Scolopacidae Tringa ochropus 14
55 Charadriiformes Scolopacidae Tringa glareola 30
56 Charadriiformes Scolopacidae Tringa brevipes 22
57 Charadriiformes Scolopacidae Xenus cinereus 170
58 Charadriiformes Scolopacidae Actitis hypoleucos 22
59 Charadriiformes Scolopacidae Arenaria interpres 59
60 Charadriiformes Scolopacidae Calidris tenuirostris 148
61 Charadriiformes Scolopacidae Calidris canutus 33
62 Charadriiformes Scolopacidae Calidris alba 1581
63 Charadriiformes Scolopacidae Calidris ruficollis 4301
64 Charadriiformes Scolopacidae Calidris pygmaea 31
65 Charadriiformes Scolopacidae Calidris minuta 3
66 Charadriiformes Scolopacidae Calidris temminckii 20
67 Charadriiformes Scolopacidae Calidris subminuta 69
68 Charadriiformes Scolopacidae Calidris acuminata 754
69 Charadriiformes Scolopacidae Calidris falcinellus 144
70 Charadriiformes Scolopacidae Calidris pugnax 1
71 Charadriiformes Scolopacidae Calidris ferruginea 381
72 Charadriiformes Scolopacidae Calidris alpina 5281
73 Charadriiformes Scolopacidae Phalaropus lobatus 5
74 Charadriiformes Glareolidae Glareola maldivarum 281
75 Charadriiformes Laridae Chroicocephalus ridibundus 821
76 Charadriiformes Laridae Saundersilarus saundersi 983
77 Charadriiformes Laridae Larus crassirostris 179
78 Charadriiformes Laridae Larus smithsonianus 294
79 Charadriiformes Laridae Larus cachinnans 2
80 Charadriiformes Laridae Larus schistisagus 41
81 Charadriiformes Laridae Gelochelidon nilotica 160
82 Charadriiformes Laridae Hydroprogne caspia 583
83 Charadriiformes Laridae Sternula albifrons 231
84 Charadriiformes Laridae Sterna hirundo 341
85 Charadriiformes Laridae Chlidonias hybrida 63
86 Charadriiformes Laridae Chlidonias leucopterus 34
87 Gaviiformes Gaviidae Gavia stellata 1
88 Ciconiiformes Ciconiidae Ciconia boyciana 23
89 Suliformes Phalacrocoracidae Phalacrocorax carbo 341
90 Pelecaniformes Threskiornithidae Platalea leucorodia 479
91 Pelecaniformes Threskiornithidae Platalea minor 227
92 Pelecaniformes Ardeidae Botaurus stellaris 1
93 Pelecaniformes Ardeidae Ixobrychus sinensis 2
94 Pelecaniformes Ardeidae Ixobrychus eurhythmus 1
95 Pelecaniformes Ardeidae Nycticorax nycticorax 129
96 Pelecaniformes Ardeidae Butorides striata 3
97 Pelecaniformes Ardeidae Ardeola bacchus 15
98 Pelecaniformes Ardeidae Bubulcus ibis 91
99 Pelecaniformes Ardeidae Ardea cinerea 439
100 Pelecaniformes Ardeidae Ardea purpurea 2
101 Pelecaniformes Ardeidae Ardea alba 264
102 Pelecaniformes Ardeidae Ardea intermedia 19
103 Pelecaniformes Ardeidae Egretta garzetta 721
104 Pelecaniformes Pelecanidae Pelecanus crispus 41

Temporal coverage


This survey was conducted monthly from July 2020 to June 2021. The specific dates were: 2020/07/16; 2020/08/15; 2020/09/26; 2020/10/30; 2020/11/17; 2020/12/07; 2021/01/17; 2021/02/21; 2020/03/18; 2021/04/15; 2021/05/21; 2021/06/16.

Usage licence

Usage licence: 
Creative Commons Public Domain Waiver (CC-Zero)

Data resources

Data package title: 
Occurrence dataset of waterbirds in the Tiaozini Wetland, the World Nature Heritage, China
Alternative identifiers: 
Number of data sets: 
Data set name: 
Occurrence dataset of waterbirds in the Tiaozini Wetland, the World Nature Heritage, China
Data format: 
Darwin Core Archive format

Our occurrence data contains 30 column labels and all data are georeferenced. Due to the limitations of bird observation, the coordinates of all species are replaced by the coordinates of the observation site.

Column label Column description
occurrenceID An identifier for the bird occurrence.
basisOfRecord The specific nature of the data record.
licence A legal document giving official permission to do something with the resource.
ownerInstitutionCode The name (or acronym) in use by the institution having ownership of the object(s) or information referred to in the record.
recordedBy A list (concatenated and separated) of names of people, groups or organisations responsible for recording the original Occurrence. The primary collector or observer, especially one who applies a personal identifier (recordNumber), should be listed first.
individualCount The number of individuals present at the time of the Occurrence.
occurrenceStatus A statement about the presence or absence of a Taxon at a Location.
eventDate The date when the event was recorded.
year The four-digit year in which the Event occurred, according to the Common Era Calendar.
month The integer month in which the Event occurred.
day The integer day of the month on which the Event occurred.
countryCode The standard code for the country in which the Location occurs.
stateProvince The name of the next smaller administrative region than country (state, province, canton, department, region etc.) in which the Location occurs.
county The full, unabbreviated name of the next smaller administrative region than stateProvince (county, shire, department etc.) in which the Location occurs.
locality The specific description of the place.
decimalLatitude The geographic latitude of the geographic centre of a Location.
decimalLongitude The geographic longitude of the geographic centre of a Location.
scientificName The full scientific name, with authorship and date information, if known. When forming part of an Identification, this should be the name in lowest level taxonomic rank that can be determined. This term should not contain identification qualifications, which should instead be supplied in the IdentificationQualifier term.
kingdom The full scientific name of the kingdom in which the taxon is classified.
phylum The full scientific name of the phylum in which the taxon is classified.
class The full scientific name of the class in which the taxon is classified.
order The full scientific name of the order in which the taxon is classified.
family The full scientific name of the family in which the taxon is classified.
genus The full scientific name of the genus in which the taxon is classified.
genericName The genus part of the scientificName without authorship.
specificEpithet The name of the first or species epithet of the scientificName.
taxonRank The taxonomic rank of the most specific name in the scientificName as it appears in the original record.
vernacularName A common or vernacular name.
taxonomicStatus The status of the use of the scientificName as a label for a taxon. Requires taxonomic opinion to define the scope of a taxon. Rules of priority then are used to define the taxonomic status of the nomenclature contained in that scope, combined with the experts opinion. It must be linked to a specific taxonomic reference that defines the concept.
taxonRemarks Comments or notes about the taxon or name.


This research was supported by the General Program of National Natural Science Foundation of China (Project No. 32171526). We are grateful to Tao Liang, Qian Han, Mengmeng Liu, Silu Wang and Huali Hu for participating in the field investigation. This research was also assisted by the Tiaozini Wetland Service Center.

Author contributions

Wei Hu – dataset preparation, manuscript preparation.

Taiyu Chen – fieldwork, species identification.

Zheping Xu – Review and upload data to GBIF.

Dawei Wu – GIS processing.

Changhu Lu – Review and editing.