Behaviour This species is fully migratory (del Hoyo et al. 1996). It breeds from May to early-August in solitary pairs, although several pairs may nest close together in optimal habitats along coasts or on islands (Johnsgard 1981, Hayman et al. 1986, del Hoyo et al. 1996, Snow and Perrins 1998). The species migrates in large flocks and is gregarious and sociable when feeding or roosting in winter, often foraging in close flocks of 10-100 or more individuals, especially in tidal areas (del Hoyo et al. 1996, Snow and Perrins 1998). 

Habitat Breeding The species breeds near the coast or up to several kilometres inland in the high Arctic, nesting on coastal plains, marshes and tundra and showing a preference for mosaics of bare rock, clay or shingle and vegetation near water or in areas that remain damp until late summer (Johnsgard 1981, Hayman et al. 1986, del Hoyo et al. 1996, Snow and Perrins 1998). Non-breeding Outside of the breeding season the species is mainly coastal, although on migration it may occur inland along dykes or on lake shores (del Hoyo et al. 1996). During the winter it frequents productive rocky and shingle shores, breakwaters, sandy beaches with storm-wracked seaweed, short-grass saltmarshes, sheltered inlets, estuaries, mangroves swamps, exposed reefs and mudflats with beds of molluscs (Hayman et al. 1986, del Hoyo et al. 1996). 

Diet Breeding On its Arctic breeding grounds the species takes Diptera (especially adult and larval midges) as well as larval Lepidoptera, Hymenoptera, Coleoptera and spiders, occasionally also taking vegetable matter early in the season (del Hoyo et al. 1996). Non-breeding Outside of the breeding season its diet consists of insects, crustaceans, molluscs (especially mussels or cockles), annelids, echinoderms, small fish, carrion and birds eggs (Johnsgard 1981, del Hoyo et al. 1996). 

Breeding site The nest is a shallow depression in mud, peat or on dry ground with dense vegetation, often positioned on a slight ridge, hummock or tussock, or in cleft or shallow fissure (Johnsgard 1981, del Hoyo et al. 1996, Snow and Perrins 1998). The species usually nests solitarily, although neighbouring pairs may nest as little as 15 m apart along coasts or on islands (where abundant feeding habitats are available) (Snow and Perrins 1998).

Almost cosmopolitan range with large populations that span all major flyways. Vast breeding range spans much of low arctic, from western Alaska (USA) and Arctic Canada (see Bart et al. in prep) east through north and north-east Greenland, northern Europe, northern Siberia east to the Chukotsk Peninsula and Bering Sea. In winter, widespread along most of the world's coastlines.

Conservation Actions Underway
The species is listed in Annex II of CMS. It is not listed on the annexes of the European Union (EU) Birds Directive, but is covered by the general protection regime provided by Article 1 of the Directive to all naturally occurring wild species in the EU. It is listed on Annex II (strictly protected) of the pan-European Bern Convention, Annex II of the Convention on Migratory Species (CMS) and Annex I of the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA). It is also listed by the Helsinki Convention (HELCOM) as a species that that is threatened and/or declining in the Baltic Sea. Across the EU, 370 Natura 2000 sites have been designated for the conservation of this species. It is included on the list of priority EU species that can benefit from a higher EU co-funding rate (up to 75%) under the LIFE Programme, although to date (June 2024) the LIFE project database lists only two projects that have taken practical conservation measures for this species. Some habitats along flyway routes are protected. Active management is also underway at some Australian sites to combat cord grass invasion, as well as protective measures implemented to reduce disturbance at roost sites (Clemens et al. 2021). The Australasian Wader Studies Group, along with BirdLife Australia's Shorebirds 2020 Project and committed volunteers continue to monitor migratory shorebirds within the East Asian-Australasian Flyway (Vine and Maurer 2016). China is investing hundreds of millions of dollars to clear tidal mudflats of Spartina cordgrass, with the aim of eliminating 90% of it by 2025; locally, this has already been successful, for example at Chongming Dongtan National Nature Reserve (Stokstad 2023). The governments of China and South Korea have halted new projects that require or depend upon land reclamation, and across the Korean Peninsula the number of coastal wetlands has increased; moreover in China and South Korea, key areas for migratory shorebirds (including A. interpres) have been identified and prioritised by government and two World Heritage nominations have been made on these grounds (IUCN 2023). Although data on scale or impact are sparse, IUCN (2023) consider that "support for coastal wetland conservation and wise-use appears to have increased over the last decade". There has been a substantial increase in the number of volunteer groups and NGOs helping to monitor the migrations of shorebirds and other waterbirds, as well as increased media coverage and special events, demonstrating enhanced awareness among coastal communities (see also EAAFP 2016). North Korea became a Party to the Ramsar Convention and joined the EAAF Partnership in 2018. In 2021, the 'Regional Flyway Initiative' (RFI) was set up by the Asian Development Bank, with technical support from BirdLife International, with the aim of protecting and restoring priority wetland ecosystems and the associated ecosystem services they provide in the East-Asian Australasian Flyway (EAAF), the most threatened flyway globally. The Initiative is slated for implementation in 10 East, South and South-East Asian countries: Mongolia, China, Bangladesh, Viet Nam, Cambodia, Lao PDR, Philippines, Thailand, Malaysia and Indonesia, all of which are used by A. interpres on northbound and southbound migrations between breeding and wintering areas, and many also for wintering. The RFI will mobilise large-scale financing to support the protection, sustainable management and restoration of at least 50 priority wetlands across ten Asian countries, with an initial financing commitment of $3 billion from the ADB (BirdLife International 2022). Over time, the RFI aims to enhance and expand the existing efforts in conserving and managing priority wetlands identified on the basis of supporting globally significant congregations of migratory waterbirds, and leverage on collaborative opportunities with stakeholders including national governments, civil society organizations, communities, regional organisations like the East Asian-Australasian Flyway Partnership. A large portion of this species' breeding population is covered by PRISM surveys in North America, enabling regular monitoring.

Conservation Actions Proposed
Ensure population monitoring continues throughout and its range, and preferably expand it to other regions (particularly in East Asia and wintering grounds in Africa where data coverage is currently patchy). In the East Asian-Australasian Flyway, the main action needed for this is the amelioration of threats on its migration. China needs to implement its plan to eliminate 90+% of Spartina cordgrass to prevent further loss of feeding habitat (much has already been lost to land reclamation; IUCN 2023). The discharge of toxic pollutants into coastal wetlands (especially where there are large shorebird congregations) needs to be controlled. Further degradation of mudflats needs to be stopped, including monitoring and preventing detrimental release of riverine sediments and responsible planning of offshore windfarms. Tools are available, such as AviStep (https://avistep.birdlife.org/) to ensure sustainable building of renewable energy infrastructure. Many of these threats, particularly development of coastal wetlands, apply also to the Arabian Peninsula where there is a need for sensible policy-making and implementation to reduce illegal killing and habitat loss (Brochet et al. 2016, de Fouw et al. 2018).