Extract only - complete publication at www.jncc.gov.uk/worldwaterbirds
Waterbirds around
the world
A global overview of the conservation,
management and research of the
world's waterbird flyways
Edited by G.C. Boere, C.A. Galbraith and D.A. Stroud
Assisted by L.K. Bridge, I. Colquhoun, D.A. Scott,
D.B.A. Thompson and L.G. Underhill
EDINBURGH, UK: THE STATIONERY OFFICE
Extract only - complete publication at www.jncc.gov.uk/worldwaterbirds
© Scottish Natural Heritage 2006
First published in 2006 by The Stationery Office Limited
71 Lothian Road, Edinburgh EH3 9AZ, UK.
Applications for reproduction should be made to Scottish Natural Heritage,
Great Glen House, Leachkin Road, Inverness IV3 8NW, UK.
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
ISBN 0 11 497333 4
Recommended citation:
Boere, G.C., Galbraith, C.A. & Stroud, D.A. (eds). 2006.
Waterbirds around the world. The Stationery Office, Edinburgh, UK. 960 pp.
Names used for geographical entities do not imply recognition, by the organisers of the Waterbirds around the world conference or other
supporting organisations or governments, of the political status or boundaries of any particular territory. Names of territories used (and
any alternatives) are included solely to help users of this publication apply information contained within this volume for waterbird
conservation purposes. The views expressed in papers included within this volume do not necessarily represent views of the editors
or the organisations and governments that supported the conference and this publication.
Cover photography:
Whooper Swans Cygnus cygnus arriving at Martin Mere, England. Photo: Paul Marshall.
(www.paulmarshallphotography.com)
Copyright of all photographs used in this publication resides with the named photographers.
Waterbirds around the world
The flyway concept: what it is and what it isn’t
Gerard C. Boere1 & David A. Stroud2
1 Dorrewold 22, 7213 TG Gorssel, The Netherlands. (email: gcboere@planet.nl)
2 Joint Nature Conservation Committee, Monkstone House, City Road, Peterborough, PE1 1JY, UK.
(email: David.Stroud@jncc.gov.uk)
Boere, G.C. & Stroud, D.A. 2006. The flyway concept: what it is and what it isn’t. Waterbirds around the world. Eds. G.C. Boere,
C.A. Galbraith & D.A. Stroud. The Stationery Office, Edinburgh, UK. pp. 40-47.
Yet despite all this complexity, many waterbird species are
highly faithful to the sites they use throughout their annual cycle
(both within and between years). Such site fidelity can be
explained as a result of various selective pressures that favour
individuals which have an intimate knowledge of their environment. Its consequence is that certain locations not only hold
large concentrations of waterbirds year after year, but that these
sites are repeatedly visited by the same birds. Further, despite
variation, migration to breeding areas is often highly synchronised, especially in those species which breed in the high arctic,
where the short breeding season makes time a critical
commodity.
In terms of the practicalities of implementing conservation
policies for migratory species there has been a clear need to
simplify the real-world complexities of migration so as to assist
consistent international cooperation between governments and
non-governmental organisations. This has been successfully
achieved through the flyway concept, defined broadly as the
biological systems of migration paths that directly link sites and
ecosystems in different countries and continents.
This short review provides some background to the flyway
concept and the various ways this has been developed over time
and has been applied in various parts of the world and for
different groups of waterbirds.
INTRODUCTION
Bird migration has always fascinated man although it is only
recently that details of international migratory routes have
become known. Whilst modern technology such as satellite
tracking has given, for some species, huge insights into the
details of migration and stopover places used, this has built on a
broad body of knowledge derived from over 100 years of birdringing using inscribed metal rings and individual colour-marks
(Davidson et al. 1999) – largely the result of volunteer efforts.
Reviewing this body of information highlights the complexities of migration (Alerstam 1990, Owen 1996, Bairlein et al.
2002, Rees et al. 2005). Migration routes and schedules can vary
by species (and by population within species – Fig. 2) and the
extent of any migratory route can vary, both by the total length of
flight-path, and the number and duration of stops along the
flight-path (Fig. 1). It can also vary according to the age and/or
sex of the bird, by season, and with weather (e.g. unfavourable
headwinds can increase number of stops used). Further, there can
be considerable variation between individuals in the same population, reflecting the fact that such variation in migration schedules (timing of migration or routes taken) is adaptive and central
to differential evolutionary fitness (Ens et al. 1994).
Such individual variation relates to trade-offs between the
eco-physiological costs and benefits of arriving earlier or later at
different locations along a migratory route (Piersma 1994).
A migration strategy that is successful in a season, say, when the
arctic summer comes early may be less successful in a year
when the arctic thaw on breeding areas comes later. Any population will contain individuals migrating at different times and
possibly using different routes, which may in any case vary
between years according to a range of environmental conditions
such as wind-speed and direction. Indeed, studies of the timing
of passerine migration in relation to changing climate provide
indications that this variation helps change migratory behaviour
at the scale of populations.
DEFINITION OF A FLYWAY
The Waterbirds around the world conference, in many of its
sessions, reviewed waterbird migration at many levels of detail:
from the long migration routes of many waders to the relative
short distance movements of, for example, intra-African
migrants such as flamingos (this volume). In almost all cases
the word “flyway” has been used to indicate the geographical
region along which the species has moved.
In line with the above, a general definition of a flyway, applicable not only for waterbirds, could be:
“A flyway is the entire range of a migratory bird species (or
groups of related species or distinct populations of a single
species) through which it moves on an annual basis from the
breeding grounds to non-breeding areas, including intermediate resting and feeding places as well as the area within
which the birds migrate.”
We emphasize that we prefer the term ‘non-breeding areas’.
The term “wintering areas” is clearly confusing in the case of
cross-equatorial migrants as well as being unsuitable for regions
were regular migration is the result of unpredictable events such
as rainfall in parts of Africa and Australia. Moreover in such cases
the movements often do not follow the same route but can be very
different from year to year pending the weather conditions.
Flyways can be considered at different scales:
Fig. 1. Different types of migratory strategy shown by waders moving
from coastal west Africa to sub-arctic breeding grounds: (from left to
right) by Turnstone Arenaria interpres (‘hop’), Dunlin Calidris alpina and
Redshank Tringa totanus (‘skip’); and Red Knot Calidris canutus and
Bar-tailed Godwit Limosa lapponica (‘jump’). Source: Piersma 1987.
40
Waterbirds around the world
•
•
•
Fig. 2. The migration systems of three populations of Brent Goose
Branta bernicla occurring in Europe. Source: after Scott & Rose 1996.
Single species migration systems. The distributional extent
of the annual migration of a species, or population within a
species, encompassing breeding staging and non-breeding
areas. Examples are given in Figs. 2 and 3. Whilst often
described as the flyways of the species concerned, such annual
distributional ranges are better described as the migration
system of the species concerned.
Multi-species flyway are defined by the Ramsar Convention
(1999) as follows: “A single flyway is composed of many
overlapping migration systems of individual waterbird populations and species, each of which has different habitat preferences and migration strategies. From knowledge of these
various migration systems it is possible to group the migration routes used by waterbirds into broad flyways, each of
which is used by many species, often in a similar way,
during their annual migrations. Recent research into the
migrations of many wader or shorebird species, for example,
indicates that the migrations of waders can broadly be
grouped into eight flyways: the East Atlantic Flyway, the
Mediterranean/Black Sea Flyway, the West Asia/Africa
flyway, the Central Asia/Indian sub-continent Flyway, the
East Asia/Australasia Flyway, and three flyways in the
Americas and the Neotropics” - (Fig. 4).
Global regions for waterbird conservation management.
At a larger scale still are global regions containing species
with similar migration systems that are the subject (actual or
potential) of shared international conservation activity –
what Hagemeijer (this volume) describes as ‘political
flyways’. Thus, the Agreement area for the AfricanEurasian Agreement on the conservation of migratory water-
Fig. 3. Examples of three different species’ migration systems within the East Atlantic Flyway for waders, showing broad migration routes from northern
breeding areas to over-wintering sites in Europe and Africa. Left to right, Kentish Plover Charadrius alexandrinus, Red Knot Calidris canutus and
Sanderling Calidris alba. Source: after Smit & Piersma 1998.
41
Waterbirds around the world
Fig. 4. The eight broad flyways of waders/shorebirds. Source: International Wader Study Group. A more detailed evaluation by Brown et al. 2001
distinguishes five shorebird flyways in North America: Pacific-Asiatic, Intermountain West, Central, Mississippi, and Atlantic.
Fig. 5. Regions of the world subject to either actual or potential multilateral agreements for the conservation of migratory waterbirds.
THE HISTORY OF THE FLYWAY CONCEPT
Previous descriptive terminology related to bird migrations have
used terms such as ‘Route of Migration’ in the context of
describing bird movements following post glacial range expansions (Dixon 1895). However, the flyway concept has become
widely used in the twentieth century because it helps to understand the problems a migratory waterbird encounters throughout
its life cycle and identifies those countries that should co-operate
to protect and sustainably manage populations.
birds (AEWA, Fig. 5) is the area that contains the migration
systems of all migratory waterbirds that occur in Africa and
western Eurasia. A similar approach has been applied to the
main flyway systems of the Asia-Pacific region (Fig. 5). It
contains multiple flyways of different waterbird taxa, and its
value is in terms of the political and governmental processes
of international co-operation (e.g. Biber-Klemm 1991).
Accordingly, it has rather little descriptive value related to
the exact movements of any bird.
42
Waterbirds around the world
Fig. 6. North American flyways used for the management of migratory
waterbirds – especially as related to the regulation of hunting.
The basic multi-species flyway concept was developed in
North America in the 1930-40s to provide a spatial management
framework for waterbirds (Lincoln 1950, Hochbaum 1955). The
system of four flyways, each with its own Council and Technical
Committee, was established between 1947-1952 to provide a
framework for co-operative management of waterfowl between
the federal government, states, provinces and non-governmental
organisations (US Department of the Interior 1959, Hawkins et
al. 1984, Linduska 1964, Nelson & Bartonek 1990, Fig. 6).
Although in Eurasia and northern Africa, a sustained
programme of international co-operation for waterbird conservation commenced in post-war years (Kuijken this volume,
Stroud et al. this volume), coherent planning for the conservation of migratory waterbirds at a flyway level started in the
1960s (Boere 2006). In the Asia-Pacific region, it effectively
commenced in the mid-1990s (Wells & Mundkur 1996).
The first flyway maps for waterbirds for western Eurasia
were published by the International Waterfowl Research Bureau
(IWRB; now Wetlands International) and Prof. Isakov of the
USSR Academy of Sciences (Isakov 1970). These maps of the
main ‘geographical’ populations’ of Anatidae in the western part
of the former USSR and Europe were published against the
background of ongoing discussions in the 1960s about an international legal instrument for the conservation of wetlands and
migratory waterfowl, which later turned into the Ramsar
Convention. Isakov (1967) recognised four major flyways for
Anatidae in western Eurasia (Fig. 7). IWRB further developed
Fig. 7. Isakov’s (1967) main geographical populations of Anatidae in
western Eurasia. Flyway coding: 1. Northern White Sea/North Sea
population; 2.European Siberia/Black Sea-Mediterranean population; 3.
West Siberian/Caspian/Nile population; and 4. SiberianKazakhstan/Pakistan-India population.
the concept, organising a specific symposium in 1976 on the
mapping of waterfowl distributions and habitats (Matthews &
Isakov 1981).
With the advent of legally binding multilateral treaties such
as the Bonn Convention on Migratory Species in 1979 and the
African Eurasian Migratory Waterbird Agreement in 1999, as
well as the more informal Asia-Pacific Migratory Bird
Conservation Strategy in 1996, the concept has proved valuable
in focusing attention on strategic needs for waterbirds migrating
within defined geographical regions. Similarly, the concept has
underpinned the rationale for many bilateral treaties (for
example Memoranda of Cooperation) between governments
focusing on the conservation of shared migratory species (see
Boere & Rubec 2002 and Boere 2003 for more details).
Different groups of waterbirds show broadly similar migration systems, although the extent to which these have all been
described – or attempted to be consolidated into broader, multi-
Table 1. Main published sources of information on the flyways of different taxa of waterbirds.
Waterbird taxa
Americas
Europe, Africa and western Eurasia
East Asia - Pacific
Ducks, geese and swans
Fig. 6.
Flyways mapped at species level only
e.g. Fig. 2. Scott & Rose 1986
Fig. 8. Flyways mapped at species level only
by Miyabayashi & Mundkur 1999
Waders
Fig. 4.
Brown et al. 2001
Fig. 4. Davidson & Pienkowski 1987,
Fig. 4. Asia-Pacific Migratory Waterbird
Smit & Piersma 1989, Stroud et al. 2004;
WI/WSG Flyway Atlas in preparation
Conservation Committee 2001; Flyways mapped
at species level by Bamford et al. in prep.
43
Waterbirds around the world
Fig 8. Generalised flyways of Anatidae in eastern Eurasia. Source: after Miyabayashi & Mundkur 1999.
LIMITATIONS TO THE FLYWAY CONCEPT
The complexity of the migration strategies and systems of individual waterbird species was noted above. Attempts to simplify
will, necessarily loose information. For example, whilst in
Eurasia (although less so in the Americas), most waterbirds
migrate in more or less north-south directions there is an impor-
species flyways – is quite varied. Table 1 summarizes main
information sources related to different flyway systems.
Flyways illustrated on different map projections can appear
quite different, and the use of different projections can in themselves give useful messages – thus a polar projection highlights
the fact that all the worlds flyways converge in the arctic.
Fig. 9. Ringing recoveries of Pochard Aythya ferina showing predominantly east-west movements across Eurasia. Source: Wernham et al. 2002.
44
Waterbirds around the world
Fig. 10. Recoveries of Lapwings Vanellus vanellus ringed or recovered in Central Siberia; showing a strong east-west migration pattern. Red symbols
refer to birds ringed in Central Siberia. Source: Veen et al. 2005.
FUTURE DEVELOPMENTS TO THE CONCEPT
The flyway concept directly and valuably supports the
‘ecosystem approach’ promoted under the Convention on
Biological Diversity (CBD) as a framework to help integrate
conservation activities and policies.
CBD describes the ecosystem approach as: ”…based on the
application of appropriate scientific methodologies focused on
levels of biological organization, which encompass the essential
structure, processes, functions and interactions among organisms
and their environment. … This focus on structure, processes, functions and interactions is consistent with the definition of
“ecosystem” provided in Article 2 of the Convention on Biological
Diversity: “‘Ecosystem’ means a dynamic complex of plant, animal
and micro-organism communities and their non-living environment
interacting as a functional unit.” This definition does not specify
any particular spatial unit or scale, in contrast to the Convention
definition of “habitat”. Thus, the term “ecosystem” does not,
necessarily, correspond to the terms “biome” or “ecological zone”,
but can refer to any functioning unit at any scale. Indeed, the scale
of analysis and action should be determined by the problem being
addressed. It could, for example, be a grain of soil, a pond, a forest,
a biome or the entire biosphere.” (CBD Decision V/6).
A flyway is in fact the totality of the ecological systems that
are necessary to enable a migratory waterbird to survive and
fulfil its annual cycle. In this sense such bird movements link
sites and ecosystem into a single functional unit, the loss of any
part of which (for example, a staging area) may jeopardise the
long-term viability of the species. Whilst some do not consider
tant component of east-west migration (see for instance Fig. 9 &
10, (Veen et al. 2005 and recovery maps in Fransson & Pettersson
2001, Bakken et al. 2003 and Wernham et al. 2002). Such
elements are not well captured in traditional flyway models.
Further, maps of generalised flyway systems conceal the
considerable between-species variation in individual migration
systems. Thus Fig. 3 highlights three quite different migration
systems for different wader species which all use the East
Atlantic Flyway.
Such limitations should not detract from the application of
the concept, although they give the scope for considerable
confusion, much of which has been apparent in the use of inappropriate flyway maps by the media and others in attempts to
describe and predict the possible spread of highly pathogenic
avian influenza by migratory waterbirds across Eurasia in late
2005. Thus the global map of wader flyways (Fig. 4) has been
widely reproduced as variously relating to all waterbirds, and
even more erroneously, as describing the movements of all
migratory birds (e.g. FAO 2005, Normile 2006, Olsen et al.
2006). Such confusion is unhelpful, especially in contexts
where potentially important policy formulation can be influenced by such misinformation, although the limitations of the
concept are recognised in the EU (Pfeiffer et al. 2006).
Thus there needs to be caution in applying the flyway
concept to other migratory birds, given that ringing recoveries of
passerines indicate widespread broad front migration across
continental land-masses (e.g. Wernham et al. 2002, Zink 1973,
1975, 1981 & 1985).
45
Waterbirds around the world
waterbirds. Ringing and Migration 19 (supplement.):
83-94.
Dixon, C. 1895. The migration of British birds; including their
post-glacial emigrations as traced by the application of a
new law of dispersal. Chapman and Hall, Ltd., London.
Ens, B.J., Piersma, T. & Tinbergen, J.M. 1994. Towards
predictive models of bird migration schedules: theoretical and empirical bottlenecks. NIOZ-Rapport 1994-5.
27 pp. Nederlands Instituut voor Onderzoek der Zee, the
Netherlands.
FAO 2005 Map of H5N1 outbreak in 2005 and major flyways
of migratory birds. Situation on 30 August 2005.
www.fao.org/ag/againfo/subjects/en/health/diseasescards/migrationmap.html
Fransson, T & Pettersson, J. 2001. Swedish Bird Ringing
Atlas. Vol. 1. Stockholm.
Hawkins, A.S, Hanson, R.C., Nelson, H.K. & Reeves, H.M.
1984. Flyways. Pioneering waterfowl management in
North America. USFWS, Department of Interior,
Washington D.C. 517 pp.
Hochbaum, H.A. 1955. Travels and traditions of Waterfowl.
University of Minnesota Press, USA. 301 pp.
Isakov, Y.A. 1967. MAR Project and conservation of waterfowl
breeding in the USSR. In: Salverda, Z. (ed.),
Proceedings of the Second European Meeting on
Wildfowl Conservation, Noordwijk aan Zee, The
Netherlands, 9-14 May 1966: 125-138. Ministry of
Cultural Affairs, Recreation and Social Welfare, The
Netherlands.
Isakov, Y.A. (ed.). 1970. International Regional Meeting on
Conservation of Wildfowl Resources (Europe, Western
Asia, Northern and Tropical Africa), Leningrad, USSR,
25-30 September 1968. Proceedings. Moscow.
424 pp.
Isakov, Y.A. & Matthews, G.V.T (eds.) 1981. Studying and
management of waterfowl in the USSR. Proceedings of
International Symposium on mapping of waterfowl
distribution, migration and habitats, Alushta. IWRB and
USSR Academy of Sciences, Moscow.
Lincoln, F.C. 1950. Migration of birds. US Fish & Wildlife
Serrvice Circular 16.
102 pp.
United States
Government Printing Office, Washington.
Linduska, J.P. (ed.) 1964. Waterfowl Tomorrow. U.S.
Department of the Interior, Washington D.C.. 769 pp.
McClure, H.E. 1974. Migration and survival of the birds of
Asia. United States Army Medical Component, SouthEast Treaty Organisation (SEATO), Bangkok, Thailand.
Miyabayashi, Y. & Mundkur, T. 1999. Atlas of Key Sites for
Anatidae in the East Asian Flyway. Wetlands
International, Kuala Lumpur.
Available at:
www.jawgp.org/anet/aaa1999/aaaendx.htm
Nelson, H.K. & Bartonek, J.C. 1990. History of goose
management in North America. Transactions of the 55th
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Normile, D. 2006. Are wild birds to blame? Science 310:
426-428.
Olsen, B., Munster, V.J., Wallensten, A., Waldenström, J.,
Osterhaus, A.D.M.E. & Fouchier, R.A.M. 2006.
Global patterns of Influenza A virus in wild birds.
that flyways should be seen as ecosystems as defined by CBD
(van der Zon pers. communication), we note that the concept has
been used within the context of recent decisions of the Global
Environment Facility, notably its support for African/Eurasian
Migratory Waterbird Flyways project. Further, CBD Decision
V/6 (above) explicitly notes the potential inclusion of wide-scale
approaches such as are provided by international waterbird
flyways.
ACKNOWLEDGEMENTS
We are very grateful to Greg Conway and the British Trust
for Ornithology for the preparation of the flyway maps presented
here.
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47