Archived 2015 topics: Curlew Sandpiper (Calidris ferruginea): request for information

Curlew Sandpiper (BirdLife factsheet) breeds across Arctic Siberia from the Yamal Peninsula to Kolyuchinskaya Gulf (N Chukotskiy Peninsula), and winters from sub-Saharan Africa through Middle East and S & SE Asia to Australasia (van Gils and Wiersma 1996).

Globally, it has an extremely large range in both the breeding season and in winter, and hence does not approach the thresholds for Vulnerable under the range size criteria (B and D2). Its population size is also extremely large (1,085,000–1,285,000 individuals; Wetlands International 2015), and hence does not approach the thresholds for Vulnerable under the population size criteria (C and D1). Therefore, the only potentially relevant criterion is A, which relates to reductions in population size. Until recently, the population was thought to be increasing, and therefore did not approach the threshold for listing as Vulnerable under criterion A (at least a 30% decline over ten years or three generations, whichever is longer).

The following summary is based on that in Wetlands International (2015):


Population breeds / winters Size (individuals) % of total Trend and sources
Central Siberia/SW Asia E & S Africa 400,000 31-37% Long term increase, apparently short term rapid decline (Nagy et al. 2014). Treated as Declining by Wetlands International (2015)
Western Siberia/West Africa 350,000-450,000 30-38% Declining (van Roomen et al. 2014)
S Asia (non-breeding) 200,000-300,000 17-25% Unknown (Wetlands International 2015)
E, SE Asia & Australia (non-breeding) 135,000 11-12% Extremely rapid decline (80.5% in three generations; Garnett 2015)
Global 1,085,000-1,285,000 Decline?

Trend in SW Asia/Middle East/East and Southern African wintering population

Nagy et al. (2014) report a long term moderate increase, and short term large decline since c.2007, based on TRIM analysis of International Waterbird Census data from 1988-2012. However, the range of this population was not very well covered, particularly in the Red Sea and southern Gulf.

A wintering population of c.45,000 at Walvis Bay and Sandwich harbour (Namibia) was stable between 1990-2013 (Simmons et al. 2015).

Trend in West African wintering population

Van Roomen et al. (2014) interpret count data from this wintering population as showing a short-term decline based on wintering counts for the period of 2003-2014 and also a long-term decline for the period of 1979-2014, however the large amount of inter-annual variation make interpretation of the data difficult. Total wintering numbers were estimated at 565,402 in the 1980s, 738,503 in the 1990s and 348,079 (rounded and raised to 350,000-450,000) in the 2010s. Dodman (2014) however estimated 875,000 and proposed to maintain the previous increasing trend of this population. Using the smoothed trend line produced by van Roomen et al. (2014) produces a decline of 32.9% over three generations (23 years), however it is uncertain whether this is truly representative.

Trend in South Asian wintering population

Reported as unknown by Wetlands International (2015).

Trend in the East Asian-Australasian Flyway population

c.11-12% of the global population uses the flyway. BirdLife Australia’s Threatened Species Committee, which applies the IUCN Categories and Criteria at the national level, recently recommended uplisting to Critically Endangered (under criterion A2bc+3bc+4bc) in Australia (Garnett 2015), and the recommendation was subsequently accepted by the BirdLife Australia Research and Conservation Committee. The proposal was based on a detailed analysis of all monitoring data collected on shorebirds around Australia and New Zealand in the last 30 years (Studds et al. in prep) – see extract here:


Annual rate of decline Generation time Loss over three generations Action Plan status 2010 Recommended status 2015
-0.075 7.6 -80.5 Endangered (Vulnerable) Critically Endangered

The analysis used Bayesian binomial mixture models of non-breeding count data throughout Australia and New Zealand to estimate trends for subpopulations thought to follow different migration routes and summarized these estimates to yield flyway-level trends. Count data for each taxon were acquired from local and national databases in Australia and New Zealand. Many counts began in the early 1980s, but several key sites initiated counts in the 1990s.

For shorebirds of the East Asian-Australasian Flyway there is considerable concern that loss of intertidal stopover habitat in the Yellow Sea region of East Asia is driving population declines (Amano et al. 2010; Yang et al. 2011). Up to 65 percent of intertidal habitat in the Yellow Sea has been lost over the past 50 years, and habitat is currently disappearing at a rate of >1 percent annually owing to reclamation for agriculture, aquaculture, and other development (Murray et al. 2014). Current rates of Yellow Sea habitat loss seem likely to continue or accelerate owing to projected human population growth, much of it concentrated along the margins of the Yellow Sea.

Declines in count data in Australia from c.85,000 in 1993 to c22,000 in 2012 (Studds et al. in prep) imply that if this decline is representative of flyway population, and if the 2007-2009 estimate of 135,000 individuals for whole EAAF flyway was correct, there would have been 382,500 birds in the flyway in 1993. This is far higher than previous estimates, suggesting either that the flyway population was previously underestimated, or that the Australian data are not representative of the whole flyway trend. Since the key threat is assumed to be loss of habitat at Yellow Sea stopover sites, and this species is one of the most dependent on these sites, the Australian declines may well be representative of the flyway. However, Amano et al. (2010) found no clear trend in Japan between 1978-2008.


Due to uncertainties over the population trend in much of the range the overall trend is very difficult to determine. However, even if the Middle East/East and South African population is assumed to be stable (despite recent indications of a rapid decline), and the South Asian population is also assumed to be stable, if the EAAF population is declining as fast as Australian data suggest, and the large West African population has declined in the manner implied by van Roomen et al. (2014), an overall decline of 32-40% in three generations may have taken place. This would imply that the species could warrant listing as Vulnerable. However, given the uncertainties outlined above, it may be appropriate to infer a more conservative rate of decline. Conversely, if there is evidence for decline in populations currently assumed to be stable, the overall rate of decline may be even higher.

Comments on all population size and trend estimates and threats to the species are welcomed, in particular from parts of the range where data are limited.


Amano, T., T. Szekely, K. Koyama, H. Amano, and W. J. Sutherland. 2010. A framework for monitoring the status of populations: An example from wader populations in the East Asian-Australasian flyway. Biological Conservation 143:2238-2247.

Bamford, M.; Watkins, D.; Bancroft, W.; Tischler, G.; Wahl, J. 2008. Migratory shorebirds of the East Asian-Australasian flyway: population estimates and internationally important sites. Wetlands International – Oceania, Canberra.

Delany, S.; Scott, D.; Dodman, T.; Stroud, D. 2009. An atlas of wader populations in Africa and Western Eurasia. Wetlands International, Wageningen, The Netherlands.

Dodman, T. 2014. Status, Estimates and Trends of Waterbird Populations in Africa: AEWA-listed African populations. Wetlands International. Consultation draft.

Garnett, S. T. 2015. BirdLife Australia Threatened Species Committee report to RACC. 23rd January 2015. Unpublished report.

Moores N., Rogers D., Kim R-H., Hassell C., Gosbell K., Kim S-A & Park M-N. 2008. The 2006-2008 Saemangeum Shorebird Monitoring Program Report. Birds Korea publication, Busan.

Murray, N. J., R. S. Clemens, S. R. Phinn, H. P. Possingham, and R. A. Fuller. 2014. Tracking the rapid loss of tidal wetlands in the Yellow Sea. Frontiers in Ecology and the Environment 12:267-272

Nagy, S., Flink, S., Langendoen, T. (2014) Waterbird trends 1988-2012: Results of trend analyses of data from the International Waterbird Census in the African-Eurasian Flyway. Wetlands International, Ede. Report 2014_10_05.pdf

Simmons, R.E.; Kolberg, H.; Braby, R.; Erni, B. 2015. Declines in migrant shorebird populations from a winter-quarter perspective. Conservation Biology 29(3): 877-887.

Studds, C. E. et al. in prep. Dependence on the Yellow Sea predicts population collapse in a migratory flyway.

Van Gils, J. & Wiersma, P. (1996). Curlew Sandpiper (Calidris ferruginea). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2014). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 23 July 2015).

van Roomen, M., van Winden, E. & Langendoen, T. (2014) The assessment of trends and population sizes of a selection of waterbird species and populations from the coastal East Atlantic Flyway for Conservation Status Report 6 of The African Eurasian Waterbird Agreement.

Wetlands International (2015). “Waterbird Population Estimates” . Retrieved from on Wednesday 22 Jul 2015

Yang, H. Y., B. Chen, M. Barter, T. Piersma, C. F. Zhou, F. S. Li, and Z. W. Zhang. 2011. Impacts of tidal land reclamation in Bohai Bay, China: ongoing losses of critical Yellow Sea waterbird staging and wintering sites. Bird Conservation International 21: 241-259

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8 Responses to Archived 2015 topics: Curlew Sandpiper (Calidris ferruginea): request for information

  1. Andy Symes (BirdLife) says:

    Hans Meltofte, chairman of the conservation committee of DOF/BirdLife Denmark, has provided the following extract from the draft of a forthcoming paper on Denmark’s most important staging area for waders outside of the Wadden Sea:

    The population of Curlew Sandpipers wintering in West Africa is estimated to number in the order of one million individuals and to have been in “strong increase” since the 1980s (Delany et al. 2009). This is confirmed by 40 years of monitoring 1964-2003 of birds on active migration past Blåvandshuk south of Tipperne, where numbers peaked in the late 1980s and early 1990s (Meltofte et al. 2006). According to the Wadden Sea monitoring, numbers of Curlew Sandpipers have been increasing during the entire period since the 1980s, however (Blew et al. 2013, JMMB XXXX).

    MELTOFTE, H. & CLAUSEN, P. in print: Trends in staging waders on the Tipperne Reserve, western Denmark, 1929-2014. – Dansk Orn. Foren. Tidsskr. 110.

  2. Richard Porter says:

    This is a common migrant/winter visitor in the Middle East, where the only countries that probably have some quantitative data over a longish period are Kuwait, Oman and UAE. It would be worth contacting the recorders directly and I will send the appropriate names directly to Andy Symes.

    This same comment will apply to Bar-tailed Godwit and a lesser extent to Great Knot, but not to Red-necked Stint which is a vagrant in the Middle East.

    Sorry that’s all I can add.

  3. Virag Vyas says:

    It is an occasional winter visitor to Western Coast of India (Gujarat). 40+ birds were sighted along the Gujarat Coast last year (2014). However it is one of the rare (Uncommon) winter visitor to India.

  4. Andy Symes (BirdLife) says:

    Preliminary proposals

    Based on available information, our preliminary proposal for the 2015 Red List would be to treat:

    Curlew Sandpiper as Near Threatened under criterion A4.

    There is now a period for further comments until the final deadline of 31 August, after which the recommended categorisation will be put forward to IUCN.

    The final Red List categories will be published on the BirdLife website in late October and on the IUCN website in November, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  5. Marc van Roomen says:

    Analyses of changes in January numbers of Curlew Sandpiper at Banc d’ Arguin (Mauritania) and Bijagos (Guinea Bissau), the two strongholds of the west African flyway population shows clear decreases. Also integrating these two sites with data from other sites in the flyway during January gives a decreasing trend. The results of the January 2014 count at the East Atlantic Flyway and the analyses with former counts will become available at 15 September 2015.

  6. Curlew Sandpiper is still one of the abundant winter visitor to both west and east coasts of India. The decline during the late 1990s and 2000s was more conspicuous. The declining and increasing trends fluctuates between wetlands, the overall trends indicate that the decline in recent years are small when compared to early 200s. The criterion A is more appropriate for this species

  7. Andy Symes (BirdLife) says:

    Recommended categorisation to be put forward to IUCN

    Following further review, there have been no changes to our preliminary proposal for the 2015 Red List status of this species.

    The final categorisation will be published on the BirdLife website in late October and on the IUCN website in November, following further checking of information relevant to the assessment by BirdLife and IUCN.

  8. Andy Symes (BirdLife) says:

    Szabolcs Nagy has provided the following comment:

    Dear All,

    Just for information, the report on Status of coastal waterbird populations in the East Atlantic Flyway 2014 is now available at This report contains the results of the trend analyses we referred to in earlier contributions.

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