Arctic Shorebird Demographics Network
The Arctic Shorebird Demographics Network (ASDN) was formed in 2009 to help organize and support work on factors limiting populations of shorebirds that nest in the arctic. The Network is a large collaborative effort that spans the North American Arctic. Fifteen organizational partners are working together to conduct demographic field research at eleven sites from Nome to Churchill. We are currently completing the 2011 field season, the second of five planned field seasons. For more information about the network, please contact
Species Focused Working Groups
The following Working Groups have been established, and more are forming soon.
Contact us if you would like to include your working group on the
web site and contact the project leaders at the web or e-mail links below for more
Hypotheses about causes for shorebird declines being addressed by each working group:
Hypotheses to explain census declines
in North American shorebirds
Rob Butler, Ron Ydenberg, Garry
Donaldson, and Stephen Brown
Pacific Wildlife Research
Centre, Canadian Wildlife Service, 5421 Robertson Road,
Delta, B.C. V4K 3N2 Canada; Centre for Wildlife Ecology,
Department of Biological Sciences, Simon Fraser University,
Burnaby B.C. V5A 1S6; Canadian Wildlife Service, Hull,
Quebec K1A 0H3, Canada;
Manomet Center for Conservation Sciences, 81 Stage Road,
P.O. Box 1770, Manomet, MA 02345 USA
R.W., R. C. Ydenberg, G. D. Donaldson and S. Brown. 2004.
Hypotheses to explain census declines in North American
Shorebird Research Group of the Americas
Report 1 (On line)
There is ample evidence that
many shorebirds counted in censuses in North America have
declined in the past two decades but the reasons for the
declines are unclear (e.g. Jehl and Lin 2001, Morrison et
al. 1994, 2001). Censuses on the eastern seaboard and
mid-west showed that 9 of 30 species were significantly
declining with most pronounced declines among species with
wide non breeding ranges in non-marine habitats (J. Bart,
pers. comm.). Trends were most detectable in the north
Atlantic and less so in the mid west. The geographic range
and number of species reported to have declined in recent
decades suggests that a general widespread cause might be at
Shorebirds breeding in North
America migrate to winter quarters in North, Central and
South America, Europe and Asia via traditional migratory
routes or ‘flyways’. Many species travel tens of thousands
of kilometres each year. Some species migrate in large
flocks that assemble at a small number of stop over sites
often populated by humans. Others migrate in small numbers
stopping at many small sites and some species exhibit both
migration behaviours. In nearly every case, shorebirds spend
part of their year in habitats altered by large numbers of
humans living nearby.
The collective wisdom of
shorebird biologists and conservationists from Canada and
the United States mostly drawn from North America was
compiled through meetings of the Canadian Wildlife Service
Shorebird Technical Committee in Quebec City, the Waterbird
Society in Lacrosse, Wisconsin in 2002, and at the 7th
Annual Western Sandpiper Research Group at Simon Fraser
University in 2003. The view of these specialists was that
the answer to why shorebirds were declining would require a
coordinated international, multidisciplinary effort across
the range of a few species which we call the Hemisphere
Shorebird Project. Emerging from these discussions were five
most likely causes for declines.
Possible causes for declines
Snow melt is thought to play an
important role in determining the timing of breeding and
reproductive success of arctic breeding shorebirds. The
Eastern Arctic is showing wider swings in temperature than
the western arctic. We predict that nesting success of
shorebirds in the eastern arctic has become more variable
than shorebirds in the west. We will test this prediction by
examining meteorological records of timing of snow melt and
air temperature at shorebird nesting areas over the past
three decades. We will relate timing of nesting and nesting
success in relation to snow melt and summer temperature at
10 sites spread from east to west across the arctic. We will
then make an estimate of expected fledging success from
archived data of snow melt over the past 30 years. The
estimates for the eastern arctic will be entered into
population models of recruitment to compare relative
population change to actual change seen in counts made on
Maritime Shorebird Surveys over the past 30 years.
2. Avoidance of predators
The recovery of birds of prey in
North America has resulted in a shift in the migration
routes, an avoidance of dangerous stop over sites, and
briefer stop over by individual shorebirds at sites that
historically held large numbers of shorebirds (Ydenberg et
al. 2001, Butler et al. 2003). We predict that shorebirds
have become more numerous in non-coastal areas that have
fewer birds of prey. We also predict that small, enclosed
sites where birds of prey can launch surprise attacks are
used by fewer shorebirds now than in the past. Finally we
predict that individual shorebirds are spending less time at
sites that give an impression that the number of birds has
The ‘trophic contamination
hypothesis’ posits that shorebirds accumulate industrial and
urban pollution at stop over sites that are subsequently
released in sudden high doses as fat is burned during
migratory flights that then disrupt their ability to make
migratory decisions. For example, large contaminant doses
might hamper refueling by reducing the satiation signal in
shorebirds so that they do not accumulate sufficient fat for
migration. In addition, organochlorines deposited on
mudflats in the 1970s and 1980s and now buried by sediments
are more accessible to long-billed shorebirds that probe
deeply for prey than short-billed species that forage at or
near the surface. We predict that OC loads will be greater
in long billed species than in short billed species. We will
compare contaminant levels of birds collected along the
migration route and on the breeding ground to determine if
contaminant loads differ greatly between flights and sites.
Within these samples, we predict that long-billed species
will carry greater OC loads than short-billed species.
This hypothesis posits that
human disturbance at stop over sites has reduced the time
available for shorebirds to accumulate fat for migration. As
a result, the shorebirds stay longer to acquire the fat or
depart for places where they can forage undisturbed. We
predict that shorebirds at stop over sites with large
numbers of people will have lower mass than the same species
at nearby undisturbed sites. We also predict that the number
of shorebirds has declined more rapidly at sites with high
human disturbance than at sites with low disturbance.
Habitat Loss and Degradation
This hypothesis posits that the
number of potential stop over sites has declined resulting
in increased competition for food so that the poorest
competitors moved to marginal foraging habitat where they
suffered higher mortality than birds in good habitat.
We will decipher the cause for
declines among the highly migratory species of shorebirds by
synthesizing existing information from various shorebird
networks and assemble teams to fill gaps in our knowledge to
complete the synthesis for species in decline. The project
would run for five years. The first year would be devoted to
the synthesis of existing data, and establishing species
networks including the enlisting of contributors. The
subsequent years will be used to collect field data to
thoroughly investigate the reasons for declines in selected
The Shorebird Research Group of
the Americas (SRGA) is a collaborative, international, and
multi-disciplinary group of biologists interested in
researching conservation questions pertaining to shorebirds
in the Americas. In the US and Canada, the SRGA advises on
shorebird science to the National Working Groups of the USA
and Canadian Shorebird Plans (Donaldson et al. 2000, Brown
et al. 2000). Participants from other countries will be
strongly encouraged and will report nationally according to
their own specific needs. Its membership includes
individuals from government, university and private
organizations. Recent concerns about possible declines in
some shorebirds in North America prompted the formation of
the SRGA and the development of the following proposal to
provide advice on the question of population stability of
shorebirds in the Americas. Coordination of this project
will be determined through consultation with SRGA partners.
The Hemisphere Shorebird Project will be coordinated through
the Centre for Wildlife Ecology at Simon Fraser University.
Each country will implement the results as they see fit. In
the US and Canada, results will be reported through the
National Working Groups of the respective Shorebird Plans.
Shorebird researchers recognize
that determining the causal factors for declining
populations is a high priority for shorebirds but that there
are additional research questions that must be addressed to
build a solid science foundation on which to base
conservation decisions. Thus, the SRGA will adapt to the
science needs of the conservation community and address
additional questions as priority needs arise.
Bart, J. and C. Francis. 2001.
Quantitative Goals for Avian Monitoring Programs.
Brown, S., C. Hickey, B.
Harrington, and R. Gill (eds.). 2001. United States
Shorebird Conservation Plan, 2nd Ed. Manomet Center for
Conservation Sciences, Manomet, Massachusetts. 70 pp.
Butcher, G. S., B. G. Peterjohn,
and C. J. Ralph. 1993. Overview of national bird population
monitoring programs and databases. Pages 192-203 in D.M.
Finch and P.W. Stangel, editors. Status and management of
Neotropical migratory birds: Proceedings of the 1992
Partners in Flight National Training Workshop, 21-25
September, Estes Park, Colorado. U.S. Forest Service Rocky
Mountain Forest and Range Experiment Station General
Technical Report RM-229.
Clark, C.W. and R.W. Butler.
1999. Fitness components of avian migration: a dynamic model
Western Sandpiper migration. Evolutionary Ecology Research
Donaldson, G. D., C. Hyslop, R.
I. G. Morrison, H. L. Dickson, and I. Davidson. 2000.
Shorebird Conservation Plan. Canadian Wildlife Service
Special Publication, Ottawa.
Jehl, J. R., Jr. and W. Lin.
2001. Population status of shorebirds nesting at Churchill,
Canadian Field-Naturalist 115: 487-494.
Morrison, R. I. G., C. Downes
And B. Collins. 1994. Population trends of shorebirds on
migration in eastern Canada 1974-1991. Wilson Bulletin
Morrison, RIG, Y. Abry, RW
Butler, GW Beyersbergen, GM Donaldson, CL Gratto-Trevor, PW
VH Johnston and RK Ross. 2001. Declines in North American
shorebird populations. Wader
Study Group Bulletin 94: 39-43.