Demography and Populations

Age at First Breeding

Individuals usually returned to their natal area and potential breeding grounds at 1–3 years of age (mean = 2) and started to breed (to mate and lay a clutch) at 1–4 years of age (mean = 2.2). The probability of breeding among returning one-year-old birds was 29% (2 out of 7) (63 Tomkovich, P. S., and E. Y. Loktionov (2021). Age of first breeding of Spoon-billed Sandpipers Calidris pygmaea. Wader Study 128(1):96–98. Close ).

Annual and Lifetime Reproductive Success

Hatching success varies significantly depending on environmental factors, such as predator pressure and prey availability for predators. For example, in years when lemming populations are low, predation on Spoon-billed Sandpiper eggs and chicks by Arctic foxes (Vulpus lagopus) increases (41 Syroechkovski, E. (2004). Brief notes on the Spoon-billed Sandpiper Calidris pygmeus Conservation Programme during summer 2004. BirdingASIA 2:68–69. Close ). At one site in 2004, eggs in ca. 50% of nests hatched and approximately 60% of young that hatched successfully fledged, with 1.65 young hatching/pair and 0.8 young fledging/pair (41 Syroechkovski, E. (2004). Brief notes on the Spoon-billed Sandpiper Calidris pygmeus Conservation Programme during summer 2004. BirdingASIA 2:68–69. Close ), but elsewhere overall breeding success has been estimated at just 7–25% and slightly lower amongst headstarted birds (42 Tomkovich, P. S. (1995). Breeding biology and breeding success of the Spoon-billed Sandpiper Eurynorhynchus pygmeus. Russian Journal of Ornithology 4: 77–91. Close , 49 Loktionov, E. Y., R. A. Digby, N. N. Yakushev, I. A. Shepelev, J. P. Clements, P. S. Tomkovich, N. S. Jarrett, N. A. Clark, R. E. Green, E. G. Lappo, and E. E. Syroechkovskiy. (2023). Evaluating the impact of headstarting on the critically endangered Spoon-billed Sandpiper Calidris pygmaea. Diversity 15(4):584. Close ). In northern Chukotka, hatching success during a favorable season was 66.7% in 1988 and 36.4% in 1986 during a poor season (42 Tomkovich, P. S. (1995). Breeding biology and breeding success of the Spoon-billed Sandpiper Eurynorhynchus pygmeus. Russian Journal of Ornithology 4: 77–91. Close ).

On average the birds reach a relatively old age with around 10 years. The oldest recorded bird has been at least 16 years (64 Zöckler, C. (2011). Saving the Soon-billed Sandpiper – an update. Birding World. 24(6): 262–264. Close ). Several other marked birds reached at least 12 and 14 years.

Annual adult survival estimated at 76%, but survival of young birds is currently extremely low and seems to be one of the major drivers of the decline (60 Digby, R., B. Hughes, and N. Jarrett (2013). Headstarting the Critically Endangered Spoon-billed Sandpiper in Russia, 2013. Avicultural Magazine 119(4):146–159. Close , 49 Loktionov, E. Y., R. A. Digby, N. N. Yakushev, I. A. Shepelev, J. P. Clements, P. S. Tomkovich, N. S. Jarrett, N. A. Clark, R. E. Green, E. G. Lappo, and E. E. Syroechkovskiy. (2023). Evaluating the impact of headstarting on the critically endangered Spoon-billed Sandpiper Calidris pygmaea. Diversity 15(4):584. Close ).

No information.

Mortality on the breeding ground among the young is high due to predation by avian predators, such as gulls and skuas, as well as Common Raven (Corvus corax), rarely Sandhill Crane (Antigone canadensis), and by mammals, like both Arctic and red fox, ground squirrels, and bears (49 Loktionov, E. Y., R. A. Digby, N. N. Yakushev, I. A. Shepelev, J. P. Clements, P. S. Tomkovich, N. S. Jarrett, N. A. Clark, R. E. Green, E. G. Lappo, and E. E. Syroechkovskiy. (2023). Evaluating the impact of headstarting on the critically endangered Spoon-billed Sandpiper Calidris pygmaea. Diversity 15(4):584. Close , 42 Tomkovich, P. S. (1995). Breeding biology and breeding success of the Spoon-billed Sandpiper Eurynorhynchus pygmeus. Russian Journal of Ornithology 4: 77–91. Close , 41 Syroechkovski, E. (2004). Brief notes on the Spoon-billed Sandpiper Calidris pygmeus Conservation Programme during summer 2004. BirdingASIA 2:68–69. Close ). Adverse weather conditions (extreme cold or very wet condition) during the chick-rearing period also cause significant chick mortality.

Adult birds are also subjected to high predation pressure. Loktionov (personal communication 2022) reported observing an Parasitic Jaeger (Stercorarius parasiticus) that pursued and killed an adult Spoon-billed Sandpiper near its nesting site. Peregrine Falcon (Falco peregrinus) and Gyrfalcon (Falco rusticolus) have also been noted attacking nesting birds in the vicinity, although specific attacks on Spoon-billed Sandpiper have not been confirmed. A dead, wounded Spoon-billed Sandpiper was found near its nest, likely bitten by an ermine (Mustela erminea).

During migration and on the wintering grounds birds are subjected to trapping, bait poisoning, accidental bycatch, and indiscriminate hunting (33 Zöckler, C., Syroechkovskiy, E.E. and Atkinson, P.W. (2010). Rapid and continued population decline in the Spoon-billed Sandpiper Eurynorhynchus pygmeus indicates imminent extinction unless conservation action is taken. Bird Conservation International. 20(2): 95–111. Close , 65 Clark, N., D. Pain, and R. Green (2014). Saving the Spoon-billed Sandpiper: an update on the conservation programme. British Birds 107(8):467–475. Close , 29 BirdLife International (2024). Species factsheet: Spoon-billed Sandpiper Calidris pygmaea. Close ). While mitigation measures have been successfully applied in Bangladesh, Myanmar and South China, hunting or bycatch pressure remains high in Vietnam, some parts of China and Russia (35 Zöckler, C., Chowdhury, S.U., Pyae Phyo Aung, Li, J., Hughes, B., Clark, N., Anderson, G. and Syroechkovskiy, E. (2018). Good progress in 2018 for Spoon-billed Sandpiper Calidris pygmaea conservation despite some setbacks. BirdingASIA 30: 21–25. Close ). Hunting appears to resume, following the military coup in Myanmar in 2021 with worsening economic conditions in the country.

It is expected that in several areas of South China and Vietnam, the Spoon-billed Sandpiper maybe accidentally caught and killed by deterrent trapping at razor clam farms (66 Liang, D., T. Mu, Z. Yang, X. Giam, Y. Wang, J. Li, S. Cai, X. Zhang, Y. Wang, Y. Liu, and D. S. Wilcove. (2024). Assessing shorebird mortalities due to razor clam aquaculture at key migratory stopover sites in southeastern China. Conservation Biology 38(2):e14185. Close ). While the direct impact of intertidal habitat loss on Spoon-billed Sandpiper mortality is unclear, the reduction in suitable feeding grounds has evidently led to starvation in parts of the population. Moores (personal communication 2020) reported finding a dead Spoon-billed Sandpiper in the reclaimed Saemangeum area of South Korea, likely a result of habitat degradation.

Lastly, diseases and pollution may also contribute to mortality among the adult birds. However, little data are available to substantiate a direct link between high levels of heavy metals and polychlorinated biphenyls (PCB) or other pollutants and the mortality of Spoon-billed Sandpiper. In 2014, a large number of waterbirds and other migratory species were found dead at a key staging areas in the Jiangsu Province near Rudong including at least two Spoon-billed Sandpiper. While pollution or avian disease may have caused this abrupt mortality during migration, the exact reason could not be determined (29 BirdLife International (2024). Species factsheet: Spoon-billed Sandpiper Calidris pygmaea. Close ).

Males establish territories that are initially ca. 6 ha, and subsequently smaller (42 Tomkovich, P. S. (1995). Breeding biology and breeding success of the Spoon-billed Sandpiper Eurynorhynchus pygmeus. Russian Journal of Ornithology 4: 77–91. Close ).

Numbers

The global population was estimated at 2,000–2,800 pairs in the 1970s, falling to 1,000 pairs in 2000 (61 Tomkovich, P.S., Syroechkovski Jr, E.E., Lappo, E.G. and Zöckler, C. (2002). First indications of a sharp population decline in the globally threatened Spoon-billed Sandpiper Eurynorhynchus pygmeus. Bird Conservation International. 12(1): 1–18. Close ), only 120–200 pairs by 2009 (33 Zöckler, C., Syroechkovskiy, E.E. and Atkinson, P.W. (2010). Rapid and continued population decline in the Spoon-billed Sandpiper Eurynorhynchus pygmeus indicates imminent extinction unless conservation action is taken. Bird Conservation International. 20(2): 95–111. Close ) and just 40 known territories in 2011 (67 Sykes, B. (2011). Saving the Spoon-billed Sandpiper: news from the field in 2011. BirdingASIA 16:13–14. Close ). Numbers at Meinypilgyno, Chukotka, which is the most consistently monitored breeding site and holds more individuals than any other known areas, declining from ca. 60 territories in 2003 to just 12 displaying males in 2009, then nine in 2012 (68 Sykes, B. (2012). Saving the Spoon-billed Sandpiper: news from the field in 2012. BirdingASIA 18:79–80. Close ) and 10–11 pairs in 2013 (69 Clark, N., D. Pain, and R. Green (2014). Back from the brink? An update on the Spoon-billed Sandpiper Calidris pygmaea conservation programme. BirdingASIA 22:22–29. Close ).

The largest numbers recorded in the 2010s are 103 and 140 seen in Jiangsu province, eastern China, in autumn 2011 and spring 2013, respectively (70 Pitches, A. (2013). News and Comment: Record flock of Spoon-billed Sandpipers in China. British Birds 106(12):704. Close , 71 China Coastal Waterbird Census Group (2015). Identification of coastal wetlands of international importance for waterbirds: a review of China Coastal Waterbird Surveys 2005–2013. Avian Research 6:12. Close ). A rigorous estimate in 2014 put the global population at 210–228 breeding pairs, with a post-breeding population of adults and immatures of 661–718 individuals (72 Clark, N. A., G. Q. A. Anderson, J. Li, E. E. Syroechkovskiy, P. S. Tomkovich, C. Zöckler, R. Lee, and R. E. Green (2016). First formal estimate of the world population of the Critically Endangered spoon-billed sandpiper Calidris pygmaea. Oryx 52:137–146. Close ); the total winter population, however, was put at only 242–378 individuals after field surveys from 2005 to 2013 (30 Zöckler, C., A. E. Beresford, G. Bunting, S. U. Chowdhury, N. A. Clark, V. W. K. Fu, T. H. Hla, V. V. Morozov, E. E. Syroechkovskiy, M. Kashiwagi, E. G. Lappo, M. Tong, T. L. Long, Y.-T. Yu, F. Huettmann, H. K. Akasofu, H. Tomida, and G. M. Buchanan (2016). The winter distribution of the Spoon-billed Sandpiper Calidris pygmaeus. Bird Conservation International 26:476–489. Close ). A 2024 global mark-resighting analysis, combined with 17 scan surveys at five non-breeding sites and using the Lincoln-Petersen method, estimated the global population of mature individuals to be 443, with a range of 330 to 550 individuals (1 Green, R. E., K. K. S. Leung, N. A. Clark, G. Q. A. Anderson, K. Brides, Q. Chang, S. U. Chowdhury, J. A. Clark, M. Foysal, C. Zöckler, Y. Gerasimov, G. A. Gale, N. Iakushev, J. Khamaye, E. Lappo, D. S. Melville, P. S. Tomkovich, E. Weston, J. Weston, and Z. Yang. (2024). New estimate of the trend in world population size of the Spoon-billed Sandpiper suggests continuing decline. Wader Study 131(2): 122–131. Close ).

Trends

The population censuses indicate a steep decline, including a population reduction of 88% between 2002 and 2009, or an estimated annual decline of 26% (33 Zöckler, C., Syroechkovskiy, E.E. and Atkinson, P.W. (2010). Rapid and continued population decline in the Spoon-billed Sandpiper Eurynorhynchus pygmeus indicates imminent extinction unless conservation action is taken. Bird Conservation International. 20(2): 95–111. Close ). However, long-term monitoring at five key sites over 17 years has provided more refined data, suggesting the current rate of decline as of 2024 is approximately 5% per year (1 Green, R. E., K. K. S. Leung, N. A. Clark, G. Q. A. Anderson, K. Brides, Q. Chang, S. U. Chowdhury, J. A. Clark, M. Foysal, C. Zöckler, Y. Gerasimov, G. A. Gale, N. Iakushev, J. Khamaye, E. Lappo, D. S. Melville, P. S. Tomkovich, E. Weston, J. Weston, and Z. Yang. (2024). New estimate of the trend in world population size of the Spoon-billed Sandpiper suggests continuing decline. Wader Study 131(2): 122–131. Close ). Although this estimate has limited precision, it nonetheless indicates a continued downward trend, emphasizing the critical need to intensify conservation efforts to prevent further losses (1 Green, R. E., K. K. S. Leung, N. A. Clark, G. Q. A. Anderson, K. Brides, Q. Chang, S. U. Chowdhury, J. A. Clark, M. Foysal, C. Zöckler, Y. Gerasimov, G. A. Gale, N. Iakushev, J. Khamaye, E. Lappo, D. S. Melville, P. S. Tomkovich, E. Weston, J. Weston, and Z. Yang. (2024). New estimate of the trend in world population size of the Spoon-billed Sandpiper suggests continuing decline. Wader Study 131(2): 122–131. Close ).

Information needed.