Bar-Tailed Godwit / Kuaka
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The annual migration of this Arctic wader across the Pacific Ocean to New Zealand has to be one of the most amazing feats of navigation, speed and endurance of any living animal. This journey, flying non-stop from their breeding grounds on the Alaskan tundra to their wintering grounds in New Zealand, a distance of around 11,700km, is achieved in just 8-9 days. To do this they must average speeds of around 55kph. By the time they reach here they will have lost 50% of their body weight.
The bar-tailed godwit is our most common Arctic migrant wader. Approximately 70-80,000 arrive each year about now and spread themselves widely around most harbours and estuaries in both North and South Islands. The larger, more preferred sites supporting the bulk of the birds are Parengarenga Harbour in Northland, Manukau, Waitematā and Kaipara Harbours and the Firth of Thames in the Auckland/Waikato region, and Farewell Spit in NW Nelson. They do however frequent many other smaller harbours, estuaries and beach sites all around New Zealand coastal areas. The Conservation Status for this species is At Risk, Declining.
Currently we are lucky to host a flock of between 80-100 godwit on the Whangamatā Harbour each year. Various counts that have been taken on the high-tide roost sites locally over the past 15 years have noted a decrease in the number of birds wintering here, down from 206 in 2010.
They arrive here about early to mid September and will remain until early March when they depart for their northern breeding grounds. While here recuperation from their southern migration efforts, resting and feeding to regain weight and refuelling for the return journey is essential.
Maybe because of more favourable weather patterns, they take a different, much longer route back to Alaska. On leaving they fly non-stop for about 7 days covering the 10,000km to reach the Yellow Sea where they congregate on the vast tidal feeding grounds near Yalu Jiang on the China-North Korea border. They rest up there for about 40 days to refuel before leaving to fly the remaining 7000km back to their Alaskan home.
The godwit is considerably taller and heavier than dotterels and has a much longer and slightly up-curved bill, pink at the base and black towards the tip. In its non-breeding plumage the feathering of both sexes is similar, mainly light brown on their upper surfaces and white below. In flight the barred tail feathers stand out and with their feet sticking out behind the tail feathers is also a distinctive feature. The males undergo a huge plumage change with the onset of each breeding season. The feathering on their heads, neck, chest and underparts erupt in a wash of rich rufous colour.
It is difficult to assign with any certainty the factors responsible for this species decline in numbers, both locally and internationally. Undoubtedly it is a combination of many, but the factors locally that are the most likely responsible are the loss of suitable high tide roosting sites within the harbour, the loss of suitable estuarine feeding grounds through accelerated siltation and mangrove incursion, and the increasingly high levels of human and dog disturbance happening on our harbour and beaches.
— John Adams. Whangamatā Harbour Care.
