The Bar-tailed Godwit (Limosa lapponica) is found in all of the world’s migratory shorebird flyways. Reflecting the global distribution of the species, a godwit has featured on the postage stamps of at least 15 countries, including Australia, and a stylised logo at one time appeared on the tail fin of aeroplanes of a national airline.
Of the 3 subspecies in the East Asian-Australasian Flyway, 2 migrate from the breeding grounds in the northern hemisphere to Australia for their non-breeding season: the baueri subspecies on the east coast and the menzbieri subspecies in Western Australia. An estimated 40% of the baueri subspecies spend their non-breeding season in Australia.
The English name is taken from the black-and-white barred tail and upper tail coverts while the term “godwit” may be derived from the Old English “god whit”, meaning “good creature”, possibly referring to its eating qualities. The subspecies baueri is named after Ferdinand Bauer who was the official artist on board the HMS Investigator when Matthew Flinders set sail in 1801 to circumnavigate Australia.
Restricted to coastal sites in Australia, the tidal flats of Moreton Bay and the Great Sandy Strait are among the strongholds for the species. Large concentrations of birds can be found; sometimes flocks of thousands at high tide roost sites. Although not their preference, godwits have been recorded roosting in mangroves.
The Bar-tailed Godwit is one of the largest migratory shorebirds (>38 cm) and most distinctive having a long and dark upturned bill with a pinkish base. The birds can be reliably sexed on bill length, the female having a longer bill. In non-breeding plumage, both males and females have a distinct brown eye-stripe with a whitish band above and extending past the eye. The brown tinged feathers of the upper parts and streaked crown give the godwit a mottled appearance. These diagnostic features separate it from the smaller Black-tailed Godwit (Limosa limosa) which has a straight bill, smooth pale greyish upperparts and as its name suggests, a noticeable black tail with a white rump in flight. Juvenile Bar-tailed Godwits have buff-tinged feathers on the upperparts giving them a striking chequered appearance.
In the austral autumn, male Bar-tailed Godwits moult into breeding plumage of almost wholly rufous head, neck and underparts with some black streaks on the sides of the breast and flanks (see photo). The females develop a far more subdued breeding plumage and some do so before northern migration.
Bar-tailed Godwits actively forage in shallow water at the tidal edge using the sensitive tip to their long bill to locate worms and shellfish in the sandy or soft mud substrates and, unlike Black-tailed Godwits, only occasionally wade in belly-deep water.
Since 2006, almost 1,200 Bar-tailed Godwits have been fitted with engraved leg flags by QWSG’s banding team revealing valuable data relating to their migration and longevity. In recent years, the fitting of satellite transmitters show the baueri subspecies undertakes the longest known non-stop flight of any bird, flying across the Pacific Ocean from its breeding grounds in Alaska to Australia and New Zealand. One of these birds, a male fitted with engraved leg flag BYX, has provided data for the entire migration in 2021 and 2022. In 2022, after a direct 6 day flight of c 7,000 km, BYX landed in South Korea where it staged for just over 4 weeks before a 4-day flight to western Alaska and then to the northernmost point to breed, the same location it used in 2021. After 2 months on the breeding grounds, BYX flew back to southern Alaska where he spent several weeks preparing for the flight to Moreton Bay. In an astonishing feat of endurance and using amazing navigation skills, BYX left Alaska in mid-September, taking 10 days to fly 10,800 km, reaching Moreton Bay on 28 September. That’s 10 days of constant wing beating (because shorebirds cannot soar or glide) without food or water flying over a featureless ocean. The image below shows the round trip undertaken by BYX.
In Queensland, the baueri subspecies is classified as vulnerable; it’s decline stemming from the loss of intertidal mudflat habitat at key migration staging sites in the Yellow Sea. However, the conservation status of the menzbieri subspecies found in Western Australia is critically endangered because, unlike the baueri subspecies, it relies on the Yellow Sea region on both northern and southern migration.
Depending on their breeding success and prevailing weather conditions, adult Bar-tailed Godwits arrive in Queensland in September and October while the juveniles arrive a little later. In March and April, the adults leave for the breeding grounds but many of the young of the previous year overwinter and in September some fly east to New Zealand where they stay until reaching sexual maturity in 2-3 years.
References:
- Hollands D. & Minton C (2012) Waders: the Shorebirds of Australia.
- Woodley, K. (2012) Shorebirds of New Zealand
- Menkhorst, P et al (2017) The Australian Bird Guide.
