Breeds in wetland habitats from the boreal forest transition in the taiga zone to the subarctic tundra (Elphick and Tibbitts 2020). On migration and in the non-breeding season occurs in a variety of wetland habitats, fresh, brackish and saltwater, including human-made habitats such as salt evaporation ponds, flooded agriculture, ponds and reservoirs (Elphick and Tibbitts 2020). Feeds on aquatic and terrestrial invertebrates, and occasionally fish and frogs.

This migratory shorebird breeds from the Alaska Peninsula, United States of America (USA) south of the north slope and east through central Canada all the way to Nova Scotia and through north central Canada from the coastal Northwest Territories, Yukon, northern British Colombia east to Hudson Bay and James Bay (Elphick and Tibbitts 2020, Fink et al. 2023). All individuals migrate from breeding areas, but a number remain in non-breeding areas each breeding season (Elphick and Tibbitts 2020, Navedo and Ruiz 2020, Fink et al. 2023). Large numbers winter in the United States in the non-breeding season, but as many migrate to the south-eastern South American grasslands (Argentina and Uruguay) and both South American coasts, scattered through high elevation wetlands in the Andes, in the Llanos of Colombia and Venezuela as well as the northern coast of South America (Elphick and Tibbetts 2020, Fink et al. 2023).

Conservation Actions In Place
Protected in U.S. and Canada under the 1927 Migratory Bird Treaty Act. Hunting is illegal in many countries within the species range, though there is allowance for subsistence hunting in Brazil and for indigenous people in Canada and the USA (AFSI 2020). In Trinidad and Tobago a ban on all waterbird hunting was enacted in 2019 (AFSI 2020). 
The Atlantic Flyway Shorebird Initiative (AFSI) has identified and undertaken a series of measures to address unsustainable harvest in the Caribbean and northern South America (AFSI 2016, 2017, 2020). An initial Potential Biological Removal estimate was generated (Watts et al. 2015). Migratory stopover habitat is largely identified and protected under the Western Hemisphere Shorebird Reserve Network (WHSRN), although this offers no legal protection.
Greater Yellowlegs is monitored via the North American Breeding Bird Survey (BBS) (Ziolkowski Jr. et al. 2022) although this covers only a small proportion of the breeding range; by the Christmas Bird Count (Meehan et al. 2022) which covers part of the non-breeding range; by the International Shorebird Survey during migration (Brown et al. 2001, Smith et al. 2023); and is partly covered by the International Waterbird Census during the non-breeding season (Wetlands International 2023).

Conservation Actions Needed
The biological and social aspects of harvest across the countries for which there is significant harvest in the species need to be fully assessed (AFSI 2016). In particular further research into harvest levels is needed in Suriname, Brazil, French Guiana, Guadeloupe and Saint-Martin and Saint Pierre and Miquelon (AFSI 2020).
Consult with the Barbados Wildfowlers Association on further lowering bag limits for the species, and delaying the start of the season to reduce the take of adult birds (Wege et al. 2014). Seek to devise, with national governments, a harvest management strategy for shorebirds in Guyana and Suriname (AFSI 2016, 2020).