Population decline in the spoon-billed sandpiper (Eurynorhynchus pygmeus) in northern Chukotka based on monitoring on breeding grounds

Abstract

The spoon-billed sandpiper is endemic of the northern Russian Far East and one of the rarest wader species in the world. During a field survey (summer 2002) of the coast of Kolyuchinskaya Bay and in lagoons located to the east, it was discovered that the species breeding population has declined by 3–5 times since the 1970s and amounted to only 42–50 breeding pairs. The reasons for this decline are uncertain. They seem to occur outside the breeding grounds, on staging or wintering areas in South Eastern Asia. The breeding productivity of the spoon-billed sandpiper is relatively low, but it did not decrease in recent decades. The breeding success in 2002 was higher than in the 1980s; however, it was still about half of the minimum level necessary to keep the local breeding population stable. Annual survival of the spoon-billed sandpiper is about 5–15% lower than in several other small Calidridinae waders. An increased mortality rather than decreased productivity appears to be responsible for the general decline of the spoon-billed sandpiper population. In the early 2000s, its total world population was estimated at 350–500 breeding pairs. The estimate of the spoonbilled sandpiper population obtained by Flint and Kondratyev (1977) is likely an overestimate.