The Red-necked Stint is often overlooked because it is our smallest Arctic migrant about the size of a sparrow. But, as Rachel Hufton reports, it is well worth looking for.
Amid the magnificent flocks of Bar-tailed Godwits, Red Knots and Wrybills at Pukorokoro Miranda, it’s easy to overlook the Red-necked Stint (Calidris ruficollis). But once seen this remarkable little sandpiper is never forgotten.
New Zealand’s smallest Arctic wader, about the size of a house sparrow, is extremely gregarious and often seen in twos, working the mudflats, head down, in a repetitive, probing, sewing machine-like motion.
The stint is most easily identified by its small size in relation to a Wrybill or Banded Dotterel. It has a streaked lateral crown and pale underparts. Head, neck and upper breast are usually chestnut brown/grey. The bill is blunt and black-tipped and it has dark legs. The pale supercillium is most prominent in non-breeding adults and juveniles. Like many other Arctic migrants, its breeding plumage develops to a rufous colour on the head and mantle.
Although radio-telemetry has told us a lot about the mystery of Bar-tailed Godwit and Red Knot migration, information for Red-necked Stint is limited due to the small body-size of the species and the limitations of current tracking devices.
Despite being the smallest wader to reach New Zealand the stint makes a staggering annual round-trip migration of 30,000 km around the East Asian-Australasian Flyway (EAAF). Flag marking of Red-necked Stints in Australia has resulted in a number of Asian sightings which has helped to unravel the mysteries of their migration route.
The latest information indicates that the stint breeds in northern Siberia, from the Taimyr Peninsula to the Bering Sea, and in north-western Alaska. It winters on the coasts of the Bay of Bengal, Malaysia, the Philippines, Indonesia and Australasia, especially south eastern Australia.
Within New Zealand, stints are widespread in small flocks that seldom exceed 25 birds. Favoured sites include Parengarenga and Manukau harbours, the Firth of Thames, Porangahau Estuary, Farewell Spit, Lake Ellesmere and Southland.
Relatively little study has been undertaken on the Red-necked Stint’s breeding behaviour. However, it is known that the male’s breeding display involves fluttering and gliding over its breeding territory while uttering a repeated call. Following its aerial display, the male drops to the ground with its wings held high in a sharp V above its back.
Nesting occurs late May-July on the tundra. The species is thought to be monogamous, producing a clutch of four buff-coloured eggs blotched with brown laid in a grass-lined depression on the ground. Incubation. Chick rearing is shared, with the young leaving the nest soon after hatching.
The diet of the stint mainly comprises small invertebrates obtained by probing and gleaning with its specialised small bill. Predominant foods include small gastropods, crustaceans (amphipods, ostracods), fly larvae and pupae, also seeds.
The global population estimate stands at c315,000 (Wetlands International 2015). It is the fifth most numerous Artic wader to visit New Zealand, with under 200 recorded annually. In recent years New Zealand numbers have declined to about 60-150 birds. Fewer than 25 remain over the New Zealand winter.
Most observations occur in the Far North, Auckland, Lake Ellesmere, the Firth of Thames and Southland. Records at Pukorokoro Miranda average three in the last 10 years. The first recorded sighting at Miranda was of four birds way back in 1941
The species is classified as Near Threatened under the IUCN Red List Category. Most of the population is restricted to the East Asian-Australasian flyway and habitat loss on the Yellow Sea is thought to be the main cause of population decline.