Atlas of Key Sites for Anatidae in the East Asian Flyway


Yoshihiko Miyabayashi and Taej Mundkur

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Atlas of Key Sites for Anatidae in the East Asian Flyway

1. Introduction

Anatidae (ducks, geese and swans) is a group of waterbirds that is ecologically dependent on wetlands for at least some parts of their annual cycle. Anatidae species use a wide range of wetlands, from the high arctic tundra, temperate bogs, rivers and estuaries, freshwater or saline lakes, and ponds or swamps, to coastal lagoons and inter-tidal coastal areas such as mud-flats, bays and the open sea. They also utilise man-made wetlands such as rice fields and other agricultural areas, sewage works, aquaculture ponds, and others. Wetlands on which these birds depend upon are usually highly productive habitats. Thus relatively small areas may support large concentrations of waterbirds. Wetlands are usually discrete and separated from each other by vast areas of non-wetland habitat. Wetlands are one of most threatened habitats in the world. In recognition of the importance of conserving wetlands for humans and nature, many countries are working towards the wise use of wetlands and increasing numbers are joining the Convention on Wetlands (Ramsar, Iran, 1971).

Many of the Anatidae populations migrate between wetlands in the northern breeding areas and southern non-breeding areas and in doing so, regularly cross the borders of two or more countries. Others move locally, within or across national boundaries largely in response to the availability of water. Thus they depend on a large network of wetlands throughout their range to complete their annual cycle. Migrations of Anatidae follow some similar general orientations, even if different species and populations have considerably different migration strategies. Within Asia, two major flyways are recognised for Anatidae. They are the Central - South Asian Flyway and the East Asian Flyway (Fig. 1).

Figure 1
Figure 1. Two major flyways for Anatidae in Asia. Central - South Asian Flyway: solid line and East Asian Flyway: broken line.

Conservation of species depends on measures by individual countries to conserve the habitat and species themselves. In dealing with migratory species such as most Anatidae, effective conservation programs can greatly benefit from internationally coordinated initiatives. One initiative is the establishment of Anatidae Site Network in the East Asian Flyway currently being developed by Wetlands International. The Network is developed under the Asia Pacific Migratory Waterbird Conservation Strategy: 1996-2000 (Wetlands International 1996) and is to be formally launched in conjunction with the 7th Meeting of the Contracting Parties of the Ramsar Convention in May 1999. Other international initiatives which will benefit Anatidae conservation include the Asian Red Data Book and Important Bird Area projects of BirdLife International. The Red Data Book is a compilation of information on threatened species while the Important Bird Area project will identify areas of importance for birds. Some of these areas will be important for Anatidae and conservation of these sites will serve to complement and extend the Anatidae Site Network.

Information on the network of key sites used by each Anatidae population is a basic requirement for the implementation of this initiative. This document aims to compile available information on key sites in the East Asian Flyway. A Directory of Asian Wetlands (Scott 1989) was the first attempt to collate information on important wetlands on a region-wide basis. Information for the Directory was collected simultaneously with the establishment of the Asian Waterfowl Census (AWC) programme. The AWC is an on-going internationally co-ordinated initiative of Wetlands International that aims to collect information on waterbirds and wetlands every January through nationally run volunteer-based networks. An analysis of the first five years of information collected by the AWC network (Perennou et al. 1994) has provided the first opportunity of examining information on important sites for waterbirds on a species basis in Asia. The AWC programme has continued to collect information since this analysis. The centralised database maintained by the Census has served as a basis for identifying key sites in this publication. Additional information, both published and unpublished, has been collected from experts in the region.

The aim of preparing the Atlas is to rapidly collate and disseminate information on the Anatidae in the East Asian Flyway. The objectives of the present document are intended to contribute to the conservation efforts of Anatidae in the East Asian Flyway by:

There will be gaps in the information provided in this Atlas, primarily due to lack of information on many areas and species and also due to existing unpublished and published information not being found or made available during its compilation. It is hoped that the publication of this document will receive constructive comments and criticisms from experts in the field, stimulate the provision of additional data, and encourage further research and surveys targeted at filling in the many gaps in our knowledge. We can expect future editions to be more comprehensive. This Atlas focuses on the East Asian Flyway and does not covers the Central Asian Flyway and populations restricted to Southeast Asia - Australasia. On the basis of information collated from the other regions and updates received after the publication of this Atlas, it is proposed that an Atlas to cover the whole of Asia will be developed by the Wetlands International (Annex I provides more information on the proposed project).

Wetlands International has published an Atlas of Anatidae Populations in Africa and Western Eurasia (Scott & Rose 1996). It provides a comprehensive review of information and definitions of flyways, biogeographic populations, selection of key sites, and others. In order to maintain consistency of approach between the two publications, for the East Asian Atlas, we have taken the liberty of quoting information from Scott & Rose (1996).

Atlas of Key Sites for Anatidae in the East Asian Flyway

2. Identification of population limits

A 'biogeographical population' comprises a discrete unit with a clearly defined range linking the breeding and moulting area to the terminal non-breeding (wintering) area, and interchange of individuals between different populations of the species remains at a low level. 'Biogeographical populations' in the East Asian Flyway are treated as separate units in this Atlas and are listed in Table 1. Several types of 'populations' are recognised (examples from the Flyway are provided in parentheses):

In order to identify 'biogeographical populations' of a species, it is necessary to delineate population boundaries based on the movements of individuals and other migration studies. A study of the movement of individuals normally relies on identifying individuals using a variety of standard marking techniques: banding (ringing) with metal bands and/or colour bands/flags, neck collars, nasal tags, radio/satellite transmitters, etc. Pioneering attempts to identify Anatidae populations in Eurasia were made by Isakov (1967, 1970) and Shevareva (1970). Information for Western Eurasia is summarised in Scott & Rose (1996).

There is no recent comprehensive review that summarises information on the status, migration routes and populations of Anatidae in Asia. Over the last 50 years or so, information on migratory routes of Anatidae in Eastern Eurasia has been collected through a number of national banding programmes, many of which originated from the large co-ordinated MAPS programme conducted between 1968 and 1971 (McClure and Leelavit 1972, McClure 1974). The work of the Bird Banding/Ringing Centres in Russia, China and Japan (Yamashina Institute for Ornithology) in particular has been instrumental in collecting and publishing a large volume of data on movements of Anatidae (e.g. Kistchinski 1979, BMRC-YIO 1985, NBBC-PRC 1987, Bianki & Dobrynina 1997). Nevertheless, there remain many gaps in the information on the migration routes and population boundaries for all species.

The concept of 'populations' based on the main wintering regions follows recommendations of Atkinson-Willes (1976) and Atkinson-Willes et al. (1982). This concept was first applied in Eastern Eurasia by Perennou et al. (1994). Waterfowl Population Estimates (Rose & Scott 1994, 1997) has largely followed Perennou et al. (1994) but has also recognised some more 'populations' not previously considered.

This Atlas also largely follows Perennou et al. (1994) and Rose & Scott (1997) and incorporates some suggestions from Anatidae experts in the flyway. These changes are covered in the species account of Anser caerulescens, Branta bernicla and Mergus merganser.

Table 1. Anatidae populations in the East Asian Flyway. Population sizes, population trends and recommended thresholds for use in 1% criterion by the Ramsar Convention and the Anatidae Site Network.
The 1% thresholds in parentheses are provisional numerical criteria for use in this Atlas, and are not yet intended as official 1% levels for the identification of sites of international importance. Population trends follow Rose & Scott (1997) and a blank indicates the absence of any information.
Species or subspecies Population Population Estimates Threshold used to select key sites
Size Trend
Dendrocygna bicolor Southern Asia / Myanmar 20,000 Decreasing 200
Dendrocygna javanica Eastern / Southeastern Asia 100,000-1,000,000 Decreasing (5,000)
Oxyura leucocephala Southern Asia (wintering) 300 Decreasing 3
Cygnus olor Eastern Asia 1,000-3,000 Decreasing 20
Cygnus cygnus cygnus Central Siberia / Eastern Asia 60,000
Cygnus columbianus jankowskii Central Siberia / Eastern Asia 40,000
Anser cygnoides Entire population: Eastern Asia 30,000-50,000 Decreasing 400
Anser fabalis middendorffii Eastern Taiga (breeding) 50,000-70,000 Decreasing 600
Anser fabalis serrirostris Eastern Tundra (breeding) 45,000-65,000 Decreasing 550
Anser albifrons frontalis Eastern Asia 100,000-150,000 Decreasing 1,250
Anser erythropus Eastern Asia 14,000 Decreasing 140
Anser anser rubrirostris Eastern Asia 50,000-100,000
Anser indicus China (wintering) 15,500-17,500
Anser indicus Southern Asia / Myanmar (wintering) 16,80018,900
Anser caerulescens caerulescens Northern Far East / Eastern Asia <300
Anser caerulescens caerulescens Northern Far East / Alaska / California / Mexico 65,000
Anser canagicas Entire population: Alaska / Northeastern Siberia / Aleutian Islands 45,000-80,000 Stable 600
Branta canadensis leucopareia Eastern Asia 0
Branta bernicla nigricans Eastern Pacific (wintering) 126,500 Stable 1,270
Branta bernicla nigricans Eastern Asia 5,000
Tadorna ferruginea Eastern Asia 50,000-100,000
Tadorna cristata Eastern Asia <50
Tadorna tadorna Eastern Asia 100,000-150,000
Cairina scutulata India - Myanmar 170
Cairina scutulata Southeastern Asia 130
Cairina scutulata Indonesia 150
Sarkidiornis melanotos melanotos Southern / Southeastern Asia 6,000 Decreasing 60
Nettapus coromandelianus coromandelianus Eastern / Southeastern Asia 25,000-1,000,000
Aix galericulata China 20,000 Decreasing 200
Aix galericulata Korea 5,000 Decreasing 50
Aix galericulata Japan 40,000 Stable 400
Anas strepera strepera Eastern Asia 500,000-1,000,000 Decreasing (7,500)
Anas falcata Entire population: Eastern Asia 500,000-1,000,000 Decreasing (7,500)
Anas penelope Southern Asia (wintering) 250,000 Increasing 2,500
Anas penelope Eastern Asia 500,000-1,000,000 Decreasing (7,500)
Anas platyrhynchos platyrhynchos Eastern Asia >1,500,000
Anas poecilorhyncha zonorhyncha Eastern Asia 800,000-1,600,000 Decreasing (12,000)
Anas poecilorhyncha haringtoni Southeastern Asia 100,000-1,000,000
Anas luzonica Philippines 2,500-10,000 Decreasing (50)
Anas clypeata Eastern / Southeastern Asia (wintering) 500,000-1,000,000
Anas gibberifrons gibberifrons Indonesia 10,000-25,000 Stable (150)
Anas gibberifrons albogularis Andaman Islands 500-1,000 Decreasing 8
Anas acuta acuta Eastern / Southeastern Asia (wintering) 500,000-1,000,000 Decreasing (7,500)
Anas querquedula Eastern / Southeastern Asia (wintering) 100,000-1,000,000
Anas formosa Entire population: Eastern Asia 210,000
Anas crecca crecca Eastern / Southeastern Asia 600,000-1,000,000 Decreasing (8,000)
Marmaronetta angustirostris Southern Asia 5,000 Increasing 50
Netta rufina Southern / Central Asia 25,000-100,000 Decreasing (500)
Aythya ferina Eastern / Southeastern Asia 600,000-1,000,000
Aythya nyroca Southern / Eastern / Southeastern Asia 10,000 Decreasing 100
Aythya baeri Entire population: Eastern / Southeastern Asia 10,000-20,000 Decreasing 150
Aythya fuligula Eastern / Southeastern Asia 500,000-1,000,000
Aythya marila mariloides Eastern Asia 200,000-400,000
Somateria mollissima v-nigra Northwestern North America / Eastern Siberia / Bering Sea 130,000-200,000 Decreasing 1,700
Somateria spectabilis Eastern Asia

Somateria fischeri Eastern Siberia / Alaska 140,000-160,000 Decreasing 1,500
Polysticta stelleri Eastern Asia / Alaska 180,000 Decreasing 1,800
Histrionicus histrionicus pacificus Western Pacific 25,000-100,000
Clangula hyemalis Eastern Asia 500,000-1,000,000
Melanitta nigra americana Eastern Asia 100,000-1,000,000
Melanitta fusca stejnegeri Central / Eastern Asia 600,000-1,000,000
Bucephala clangula clangula Eastern Asia (wintering) 50,000-100,000
Mergellus albellus Eastern Asia (wintering) 25,000-100,000
Mergus serrator serrator Eastern Asia (wintering) 25,000-100,000
Mergus squamatus Entire population: Eastern Asia 2,000-4,000 Decreasing 30
Mergus merganser merganser / orientalis Southern Asia (wintering) 2,500-10,000 Stable 60
Mergus merganser merganser / orientalis Eastern Asia (wintering) 50,000-100,000

Atlas of Key Sites for Anatidae in the East Asian Flyway

3. Methods

3.1 Regional scope

The Atlas covers the arctic region of Siberia to the Far East of Russia and Alaska in the United States of America, south through Mongolia, People's Republic of China, the Korean peninsula, Japan, Southeast Asia and the Philippines.

3.2 Taxonomic scope, treatment and nomenclature

Species and populations of Anatidae in the East Asian Flyway refers to the birds that breed and migrate within Eastern Asia during their annual cycle (Table 1). The breeding range, staging and moulting sites and non-breeding areas of several Anatidae populations extend into Central and Southern Asia in the west and into North America in the east and these populations are included. All Australasian species and populations are excluded. Species which occur in Eastern Eurasia only as rare vagrants or stragglers from other regions are also excluded.

Although listed in Table 1, no account is provided in the Atlas for:

Species and populations which occur in the region only as a result of introductions by man (e.g. a feral population of Cygnus olor in Japan) have been excluded.

Taxonomic treatment at species level follows Sibley & Monroe (1990, 1993). Information on subspecies has been derived from a number of sources, the principal references being del Hoyo et al. (1992) and Madge & Burn (1988). Common names closely follow Sibley & Monroe (1990).

3.3 Data sources

A large amount of new count information originates from the Asian Waterfowl Census (AWC). The AWC has been in operation since 1987. The programme is currently co-ordinated by Wetlands International - Asia Pacific and prior to 1996 was co-ordinated by the International Waterfowl and Wetlands Research Bureau and Asian Wetland Bureau. The data is stored in a central database and data for 1987-1996 has been reassessed for this project to identify key sites for Anatidae. The Environment Agency of Japan has offered the data of national annual counts of Anatidae in January 1997 for assessment of this project.

A large number of experts have offered additional data and reports. An attempt to locate information from literature has yielded additional data. However, the limited time available for this project has not permitted a comprehensive review of literature, adequate consultation and peer review of the information collated.

All these data have been stored in a database for this project and have been used for the identification of key sites. Details of the structure of the database are provided in Annex I.

3.4 Population estimates

The estimates of populations used in this Atlas are identical to those published in the second edition of Waterfowl Population Estimates (Rose & Scott 1997), unless stated otherwise. Where a population estimate differs from that in Rose & Scott (1997), justification for a new estimate is given in the species text under the heading 'Population size'. All population estimates and the 1% criterion derived from them are given in Table 1.

In most cases, estimates of total size of populations are based on the population in the non-breeding period. In cases where the total population size is derived from an estimate of the breeding population, the number of individuals in the population is calculated as three times the number of breeding pairs. This formula has been proposed by Meininger et al. (1995), and is adopted by Rose & Scott (1994, 1997). The formula has been tested for Anser indicus in this Atlas.

Some Anatidae populations in the East Asian Flyway have not been sufficiently covered by the Asian Waterfowl Census and other co-ordinated annual censuses. In these cases, population sizes have been provided in the form of a very broad range. Most of these population sizes are derived from published literature. A lot of new information has been contributed by Anatidae experts since the Action Plan for Anatidae workshop organised in Kushiro, Japan, in 1995. The 'provisional numerical criterion' for selection of sites in this Atlas has been set at 1% of the middle of the range, following Scott & Rose (1996). Thus, for example, the numerical criterion for a population estimated at between 100,000 and 1,000,000 would be 1% of 550,000, which when rounded off is 5,000.

3.5 Selection of key sites

The Ramsar Convention has adopted several criteria for the identification of wetlands of international importance. Criterion 3a states: "A wetland should be considered of international importance if it regularly supports 20,000 waterfowl." (Annex I to Recommendation 4.2, Montreux, Switzerland, 1990). This criterion refers to all waterfowl as defined by the Convention, including Anatidae. A preliminary list of key sites that support 20,000 or more individuals of Anatidae, comprising one or more species identified in the Project is presented in Annex II. The list includes sites identified on the basis of single or more counts and estimations of the number of single or several Anatidae species. These sites are presented in a map (also in Annex II).

Principles to identify key sites for individual species and populations of Anatidae have been laid out by Scott & Rose (1996). This Atlas follows similar criteria and a key site is selected on the following basis:

In the table of key sites in each species account, the inclusion of a site is explained by an importance code (Table 2). Additional information on the criteria follows in this section.

Table 2. Selection criteria for key sites.
Importance code Reason for selection
1 Five or more counts available between 1988 and 1997 with an average of the last five counts exceeding 1% of the population size.
2 An average of the last five counts exceeding 1% of the population size but the first of these counts is prior to 1988
3 Five or more counts available between 1988 and 1997 of which three or more exceed 1% of the population size, but the average count does not.
4 Three of the last five counts exceed 1% of the population size but the average does not and the first of these counts is prior to 1988.
5 Less than five counts are available but three counts have exceeded 1% of the population since 1988.
6 Less than five counts are available but three counts have exceeded 1% of the population, the first of these prior to 1988.
7 The site qualifies as a potential harsh weather or drought refuge only.
8 At least one count exceeding 1% of the population size but less than three of the last five counts available between 1988 and 1997 reach this value and the average of the last five counts is less than 1% of the population size
9 Same as for code 8, except that the last five counts started prior to 1988
10 Less than five counts available and less than three counts exceeding 1% of the population size but the average of all counts exceeds 1% of the population size.
11 Less than five counts available of which one or two exceed 1% of the population size but the average of all available counts does not. This code is also used for concentrations of globally threatened species thought to be important despite being below 1% of the population size, and for concentrations of very large populations that exceed 20,000 individuals yet fail to exceed 1% of the population size.

i) The 1% criterion

The basic criterion used for selection of key sites in this Atlas is the 1% criterion. This is one of the Ramsar Convention Criteria developed for the identification of wetlands of international importance for Ramsar Sites. Criterion 3 of the Convention states: "A wetland should be considered internationally important if: (c) where data on populations is available, it regularly supports 1% of the individuals in a population of one species or subspecies of waterfowl" (Annex I to Recommendation 4.2, Montreux, Switzerland, 1990). This 1% level is applicable throughout the range of that population and at any time of the year.

It is essential that the term 'regularly' be defined to enable proper application of this criterion. There have been a series of discussions and recommendations on this subject, e.g. Atkinson-Willes et al. (1982) for Eurasia and Perennou et al. (1994) for the Asian region. This Atlas follows Perennou et al. (1994) in the selection of key sites and identifies sites that support:

ii) Criteria for globally threatened species

The Ramsar Convention has adopted a criterion (2a) that relates specifically to threatened species or subspecies of plants and animals and states: "a wetland should be considered internationally important if it supports an appreciable assemblage of rare, vulnerable or endangered species" (Annex I to Recommendation 4.2, Montreux, Switzerland, 1990). The IUCN Red List provides the global standard for 'rare, vulnerable and endangered species' (but does not consider subspecies). The most recent edition of the Red List was published in 1996 (IUCN 1996). Green (1996) has published a list of globally threatened Anatidae taxa at the species or subspecies level. Data for Eastern Eurasian populations is summarised in Table 3.

In addition to the sites that support more than 1% of a population of a globally threatened species or subspecies, sites that regularly support an 'appreciable assemblage' of individuals of some of these species or subspecies are also included in the list of key sites in this Atlas. There has been no guidance on the interpretation of the words an 'appreciable assemblage'. For species that are highly gregarious outside the breeding season, application of the 1% criterion alone will select sites holding the great bulk of the population, and there may seem to be little need for an additional, lower numerical criterion. For species with highly dispersed distribution, strict application of the 1% criterion will select only a small number of 'super' sites. Scott & Rose (1996) have included sites that regularly support over 50 individuals (or 15 breeding pairs) of a globally threatened species in the list of sites identified as being of international importance.

For the purposes of the present Atlas, levels below 1% have been selected provisionally for globally threatened species based on the ecology and biology of the species concerned: Aythya nyroca, Aythya baeri, Polysticta stelleri and Mergus squamatus.

Table 3. Threatened and near-threatened species of Anatidae in Eastern Eurasia (as listed by IUCN 1996 and Green 1996). An asterisk mark indicates the species or subspecies for which key sites supporting an 'appreciable assemblage' were selected in this Atlas.
English name Scientific name IUCN (1996) Green (1996)
White-headed Duck Oxyura leucocephala Vulnerable Vulnerable
Swan Goose Anser cygnoides Vulnerable Vulnerable
Middendorf's Bean Goose Anser fabalis middendorfi - Vulnerable
Thick-billed Bean Goose Anser fabalis serrirostris - Vulnerable
Lesser White-fronted Goose Anser erythropus Vulnerable Vulnerable
Aleutian Canada Goose Branta canadensis leucopareia - Vulnerable
Crested Shelduck Tadorna cristata Critically endangered Critically endangered
Indonesian White-winged Duck Cairina scutulata scutulata


Indo-Malaysian White-winged Duck Cairina scutulata leucopterus Endangered
Mandarin Duck Aix galericulata Near-threatened not listed
Philippine Duck Anas luzonica Near-threatened Vulnerable
Andaman Teal Anas gibberifrons albogularis Critically endangered Critically endangered
Baikal Teal Anas formosa Vulnerable Vulnerable
Marbled Teal Marmaronetta angustirostris Vulnerable Vulnerable
Salvadori's Duck Salvadorina waigiuensis Vulnerable Vulnerable
Ferruginous Duck * Aythya nyroca Vulnerable Vulnerable
Baer's Pochard * Aythya baeri Vulnerable Vulnerable
Spectacled Eider Somateria fischeri Vulnerable Endangered
Steller's Eider * Polysticta stelleri Vulnerable Vulnerable
Scaly-sided Merganser * Mergus squamatus Vulnerable Endangered

iii) Key sites for breeding birds

The 1% criterion is applicable year round, thus any site which supports 1% of a population during the breeding season is included in this Atlas. There has been considerable discussion (see for example Scott & Rose 1996) on the difficulties in selecting key breeding areas on the basis of the 1% criterion. This is especially relevant to the northern latitudes and in arid regions where many species breed in low densities. Information on the breeding areas of species in the East Asian Flyway is incomplete. Breeding sites identified as important on the basis of numerical data in the literature are provisionally included in the list of key sites.

Atlas of Key Sites for Anatidae in the East Asian Flyway

4. Species Accounts and Maps

4.1 Species accounts

The species accounts contain information under the following headings:

Classification: a note on the species and subspecies, with IUCN category for the threatened taxa listed in IUCN Red List (IUCN 1996) and/or in Green (1996).

Distribution: a brief description of the world range of the species, with special emphasis on its distribution within Eastern Eurasia.

Movements: brief information on the movements of the species and special emphasis on its migration in Eastern Eurasia, as deduced from banding and migration studies. This information has been taken from published literatures, and no attempt has been made to undertake any new analyses of banding results.

Population limits: a description of those 'populations' of the species which should be treated as separate units for conservation purposes. This is justified as far as possible on the basis of known movements of the species. In many cases, it is accepted that these 'populations' overlap extensively with other populations of the species, and cannot therefore be justified on biological grounds. Justification then rests on the desirability of separating the individuals in a species or subspecies into geographical units which are of a manageable size for conservation purposes.

Population size: an estimate of population size for each of the 'populations' identified in the foregoing section. Two types of estimates are presented: those which are considered to be sufficiently reliable to be used in the identification of sites of international importance of the Ramsar Convention and Anatidae Site Network on the basis of the 1% criterion; and those which are not. The latter, usually given in the form of a very broad range, are presented as 'best guesses' of population size, and are used to derive a 'provisional numerical criterion' for the identification of key sites for this Atlas. When the estimate follows that given in Waterfowl Population Estimates (Rose & Scott 1997), reference is made to the original source of the estimate. When the estimate differs from that given by Rose & Scott (1997), justification for the revised estimate is given in the ensuing text. In many cases, an attempt has been made to revise the estimate by compiling the most up-to-date information that has been contributed by Anatidae experts in the countries in the flyway.

4.2 Table of key sites

Information of key sites is provided on a species and population level. The table is listed for each country in order of approximate location from north to south, and in each country the order of sites is from north to south.

Information on key sites presented in the table is as follows:

4.3 Maps

For each species included in this Atlas, a map is given showing the approximate limits of the populations as identified in the text. Population boundaries are solid lines if they are based on good biological data. If the boundaries are poorly known or have very little biological significance, they are represented by broken lines. Thus broken lines are often used to delineate the main breeding ranges of migratory species when there is known to be a considerable amount of overlap between different 'populations' on their breeding grounds.

Approximate boundaries of breeding ranges of species are indicated by a dotted line. This information has been taken from the existing published literature; the main sources are Cheng (1976, 1979, 1987), del Hoyo et al. (1992), Grimmett et al. (1998), Scott & Rose (1996) and Poyarkov, N. (pers. comm).

All key sites are plotted as solid circles. Details of the key sites are presented in the table of key sites in the species account. The exact location of a few sites listed in the table is not known and these are not plotted in the maps.

This document focuses on the East Asian Flyway, the regional scope of which is outlined in Section 3.1. However some species or populations have population limits or migration strategies that do not follow the two major flyways in Asia (see Figure 1). There are some species with a single population that covers a large area of Asia (e.g. Aythya nyroca). Some populations of other species extend outside the regional scope of this Atlas (e.g. Anser indicus, Sarkidiornis melanotos). Key sites for these populations are known to exist outside the regional scope of this Atlas, but they are not documented in this publication.