The bar-tailed godwit (Limosa lapponica) is a large and strongly migratory wader in the family Scolopacidae, which feeds on bristle-worms and shellfish on coastal mudflats and estuaries.

[2] The bar-tailed godwit was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Scolopax limosa.

[3] It is now placed with three other godwits in the genus Limosa that was introduced by the French zoologist Mathurin Jacques Brisson in 1760.

[4][5] The genus name Limosa is from Latin and means "muddy", from limus, "mud", referring to its preferred habitat.

The adult has blue-grey legs and a long, tapering, slightly upturned bi-coloured bill: pink at the base and black towards the tip.

[11] Non-breeding birds seen in the Southern Hemisphere are plain grey-brown with darker feather centres, giving them a striped look, and are whitish underneath.

[13][14] All bar-tailed godwits spend the Northern Hemisphere summer in the Arctic, where they breed, and make a long-distance migration south in winter to more temperate areas.

One specific female of the flock, nicknamed "E7", flew onward from China to Alaska and stayed there for the breeding season.

[17] In 2022, a godwit numbered 234684 left Alaska on 13 October and flew non-stop to Tasmania, the first time a tagged bird has flown this route.

[19] Both Australasian subspecies head north to their breeding grounds along the coast of Asia to the Yalu Jiang coastal wetland in the north Yellow Sea, the most important staging grounds for godwits and great knots (Calidris tenuirostris) in their northern migration.

L. l. menzbieri spent on average 38 days in the Yellow Sea region and flew an additional 4,100 km (2,548 mi) to high Arctic Russia.

[16] Birds will often depart early from New Zealand if there are favourable winds; they seem to be able to predict weather patterns that will assist them on the entire migration route.

[23] Godwits arrive at the Yukon-Kuskokwim Delta in Alaska in two waves; local breeders in early May, and larger flocks in the third week of May en route to breeding grounds further north.

[28] In a major staging site in the northern Yellow Sea, they continue to hunt polychaetes, but most of their food intake is the bivalve mollusc Potamocorbula laevis, which they generally swallow whole.

In a study at the Manawatū Estuary, shorter-billed birds (males) fed mostly on small surface prey like Potamopyrgus snails, half being snail specialists, whereas females consumed more deeply-buried prey such as worms; the birds also displayed some individual food preferences.

[30] During breeding season, shore birds such as bar-tailed godwit will exhibit conspicuous acts such as song flight, courtship, copulation and antagonistic behaviour.

In general, larger godwits have greater flight costs, which accounts for the difference in travel expenses.

Those flight lengths are sufficient to allow the individuals from northern New Zealand potentially to Japan or South Korea.

This species is able to "ride" high-pressure systems over the Tasman Sea during the first part of their migration from New Zealand, and so they are most likely to receive wind assistance to Australia.

[43] Sometimes during Southward migration, they will make some stopovers in different staging sites if their destinations are likely to be father north than Australia or Papua New Guinea and Irian Jaya.

[45] These altered routes are suggested to be adaptive reactions to the risks of continuing to fly over open oceans when the wind is unfavourable.

[45][46] This migration strategy of Australasian bar-tailed godwits is exemplify by their exceptional travels, which cross hemispheres and encompass 10,000 km, and their reliance on a few number of refueling sites.

[1] Fewer birds have been using East African estuaries since 1979, and there has been a steady decline in numbers around the Kola Peninsula, Siberia, since 1930.

[1] Both L. l. bauri and L. l. menzbieri adult survival rates decreased between 2005 and 2012, probably because of the loss of intertidal staging areas in the Yellow Sea.

[53] They are quite sensitive and easily spooked so it prevents them from disturbance at high tide roosts which leads to stress since they could not rest.

We need to contribute to their conservation measures to help maintain their population by restricting human access, creating protected zones and keeping safe distance from bar-tailed godwits.

[54][55] The bar-tailed godwit is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.