Birds < Waterbirds > Reptiles
Other groups — Birds: Waterbirds and Plovers

Waterbirds are broadly defined as "birds ecologically dependent on wetlands" and include traditionally recognised groups popularly known as wildfowl, waterfowl and shorebirds/waders. Cranes, ducks, geese and swans are revered in many cultures, while other species are considered as quarry species or agricultural pests.

Figure 4.6 shows the families classified as "waterbirds" within GROMS, the plovers and lapwings (shorebirds) are shown in Figure 4.7. A high percentage of waterbirds are migratory. Most species prefer certain flyways (Figure A2.75) and staging areas (Figure A2.39), forming important links among eco-systems. Wetlands are key habitats as breeding and non-breeding grounds, or as "stepping stones" for resting and feeding (see chapter 5.2 for a summary of threats to wetlands). Waterbirds
occur there in high numbers and concentrations, and therefore are an important component within food webs and nutrient cycles of these temporarily productive ecosystems.

"Wetlands International" is among the most important organisations for monitoring and conservation of waterbirds.35 It organises regular waterbird counts worldwide, covering a network of several regional offices and a total of around 20,000 monitoring stations. Wetlands International maintains databases on population numbers, which are published in regular intervals (e. g. Delany et al. 1999). The "Atlas of Anatidae populations in Africa and western Eurasia" by Scott & Rose 1996 contains maps and staging areas, and a Wader Atlas is in preparation. However, these data are not yet accessible in digital format. Several of the maps published by Scott & Rose (1996) have been digitised by the GROMS.

For seven threatened duck species, point data of Eurasian staging areas (as listed by Scott & Rose 1996, pp. 257ff.) were added to the respective distribution maps from various sources (Figures A2.28-A2.34). Though the correlation seems to be reasonably good at first glance, a closer look reveals some interesting discrepancies, which may deserve further investigation. Once databased, the number of species per staging post can be calculated. This operation resulted in the diversity map shown in Figure A2.39, which shows hotspots of highest species numbers. More than 20 species aggregate at the Azov Sea (Russia), Miankaleh and Gorgan Bay (Iran), the Manych-Godilo Lakes (Russia), Kelifskiye Lakes (Turkmenistan), the Parc National des Oiseaux du Djoudj (Senegal) and the Inner Niger Delta (Mali). One has to keep in mind that these sites are also important for many other bird species and fishes. Besides these "hotspots" of diversity, there are areas with few species, but huge numbers of individuals. Examples are the Wadden Sea (North Sea, see Figures A2.15, A2.39) or Chesapeake Bay (USA), where numbers of staging waterbirds go up into hundreds of thousands.

In a similar way, point data for the nearly extinct slender-billed curlew (Numenius tenuirostris) were intersected with sites protected under the European Union Birds Directive (Special Protection Areas, SPAs) and Ramsar sites. The resulting map (Figure A2.36) clearly indicates those localities where the species would be without protection – if it ever reappears at all.

Cranes (Gruidae) are probably the most famous flagship species among the waterbirds. They are a focus of CMS conservation activities, including a Memorandum of Understanding for the highly endangered Siberian Crane (Figure A2.46). Figures A2.41-45 show distribution maps and flyways, together with further details on the conservation status of these severely threatened birds.36 Further maps for waterbirds listed on CMS Appendix I include the Chinese egret (Egretta eulophotes, Figure A2.38), the oriental white stork (Ciconia boyciana, Figure A2.47) and the flufftail (Sarothrura ayresi, Figure A2.67). All five flamingo species are migratory and listed on CMS Appendix II, and two of the South American flamingos on both CMS Appendices (Figures A2.51, A2.52).

Fig. 4.6: Number of migrants within waterbird families.

Total bar: species numbers within the family, according to del Hoyo et al. (1992, 1996). The number of migrants is given and indicated by the black section. Entire families listed on CMS Appendix II are marked.

Abb. 4.6: Anzahl der wandernden Arten innerhalb der Wasservogel-Familien.

Balken (gesamt): Artenzahlen innerhalb einer Familie nach del Hoyo et al. (1992, 1996). Die Anzahl wandernder Arten wird durch die schwarze Markierung sowie die nebenstehende Zahl wiedergegeben. Werden ganze Familien im Anhang II der Bonner Konvention gelistet, so ist dies vermerkt.

Fig. 4.7: Number of migratory plovers, sandpipers and snipes (shorebirds).

Total bar: species numbers within the family, according to del Hoyo et al. (1996). The number of migrants is given and indicated by the black section. Entire families listed on Appendix II are marked.

Abb. 4.7: Anzahl der wandernden Arten innerhalb der Regenpfeifer, Strandläufer und Schnepfen (Küstenvögel).

Balken (gesamt): Artenzahlen innerhalb einer Familie nach del Hoyo et al. (1996). Die Anzahl wandernder Arten wird durch die schwarze Markierung sowie nebenstehende Zahl wiedergegeben. Werden ganze Familien im Anhang II der Bonner Konvention gelistet, so ist dies vermerkt.

Around 100 species of migratory Anatidae cross international borders and are included within CMS Appendix II, and around half of them are covered by the African-Eurasian waterbird agreement (Figure A2.26). This special framework has been developed for all waterbirds occurring in Africa or parts of Asia depending on wetlands, covering 172 bird species including plovers, lapwings, snipes and waders. All of these families have a high proportion of migrants, and all migratory plovers (Charadriidae), sandpipers and snipes (Scolopacidae) are listed on CMS Appendix II. The buff-breasted sandpiper (Tryngites subruficollis: Scolopacidae) is a Nearctic migrant recently added to CMS Appendix I, because of its restriction of wintering grounds in Argentine grasslands (see Figure A2.58 for further details).

Among the Charadriiformes, several species are on the brink of extinction, such as the slender-billed curlew (Numenius tenuirostris, Figure A2.36) and the Eskimo curlew (Numenius borealis, Figure A2.37). Populations of the once highly abundant sociable plover (Vanellus gregarius) have recently collapsed for unknown reasons, and the species seems to enter the same "road of extinction" (Figure A2.49, and references in caption).

Among the 20 migratory spoonbills and ibises (Threskiornithidae), the hermit ibis (Geronticus eremita) belongs now to the most endangered bird species on earth (Figure A2.53, and references therein). An unfavourable conservation status is reported for the endangered black-faced spoonbill (Platalea minor), which is restricted to only one breeding population in East Asia, and is therefore suggested for listing by CMS (Table 4.8).

There are around 50 migratory rails (Rallidae). Among the endangered species is the white-winged flufftail (Sarothrura ayresi), one of the rarest and least known African endemics (Figure A2.67). While this species is listed on both CMS Appendices, the threatened Swinhoe’s rail (Coturnicops exquisitus) should be considered for inclusion (Table 4.8). Like many other rails, this poorly known species suffers from loss and fragmentation of wetlands in its breeding and wintering ranges in Eastern and Southern Asia (BirdLife International 2000).

Threats and conservation efforts for waterbirds are intimately linked to their wetland habitats. Modification and destruction of wetlands by humans started with the rise of agriculture. A considerable number of species adapted to the modified agricultural ecosystems, at least for part of their life cycle. For example, cranes (Grus grus) feed on corn or peanut fields within their wintering ranges in Spain or the Hula valley in Israel ( Rice fields or artificial lakes are other examples for successful adaptations of waterbirds. This equilibrium can easily be destroyed by application of pesticides or changes in landuse. For example, Lane & Fujijoka (1996) have shown that irrigation by concrete canals deprived egrets of their productive foraging habitat, at the edges of traditional earthen irrigation channels. The construction of the Three Gorges Dam in China (Topping 1995) will affect wintering habitats of the Siberian crane (Grus leucogeranus) and those of the red-crowned crane (Grus japonensis), by altering sedimentation processes of its downstream wintering marshes (Figures A2.43, A2.45). Further large-scale projects affecting wetlands are discussed in section 4.4 (Table 4.13), and mapped in Figure A2.40.

The Convention on Wetlands, signed in Ramsar, Iran, in 1971, is an intergovernmental treaty which provides the framework for the conservation and wise use of wetlands. In fact, the original convention text ( is entitled: "Convention on Wetlands of International Importance especially as Waterfowl Habitat", and recognises in its preamble that"waterfowl in their seasonal migrations may transcend frontiers and so should be regarded as an international resource," thereby anticipating a fundamental principle of the Bonn Convention. There are at present 124 contracting parties to the Convention, with 1072 wetland sites, totalling 81.75 million hectares, designated for inclusion in the Ramsar List of Wetlands of International Importance ( Figure A2.39 shows a map of Ramsar sites in the Wadden Sea area.37 Figure A2.40 shows that a considerable number of important staging areas for ducks are Ramsar sites. The cooperation between CMS, RAMSAR and the AEWA secretariat is close, and already resulted in numerous joined projects aiming at the protection of whole ecosystems and entire species assemblies. Water- and shorebird management plans are among the most advanced schemes developed by conservationists. Most of them have a "flyway approach", concentrating their efforts along flyways (Figure A2.75, with hyperlinks to some flyway conservation plans).

The huge seasonal concentrations of waterbirds attract hunters, and mortality of threatened and protected species is high. Several of these species are so similar to related quarry birds, that a differentiation in the field seems to be impossible. Examples are the lesser white-fronted goose (Anser erythropus), and possibly even the slender-billed curlew (Numenius tenuirostris) (for details, see Figures A2.28 and A2.36). Indirect effects come from disturbance (see Figure A2.50) and lead shot poisoning (Thomas 1997).

35 Wetlands International:
36 The International Crane Foundation (ICF) is dedicated to the study and conservation of these higly endangered birds: see
37 The GROMS-CD contains a GIS point layer of all Ramsar areas as by June 2000: (../geodata/general/ramsar.shp)
Birds < Waterbirds > Reptiles
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This document should be quoted as part of the publication "Riede, K. (2001): The Global Register of Migratory Species ­ Database, GIS Maps and Threat Analysis. Münster (Landwirtschaftsverlag), 400 pp." + CD

 by Klaus Riede