The austral snipes, also known as the New Zealand snipes or tutukiwi,[1] are a genus, Coenocorypha, of tiny birds in the sandpiper family, which are now only found on New Zealand's outlying islands. There are currently three living species and six known extinct species, with the Subantarctic snipe having three subspecies, including the Campbell Island snipe discovered as recently as 1997. The genus was once distributed from Fiji, New Caledonia and Norfolk Island, across New Zealand and southwards into New Zealand's subantarctic islands, but predation by introduced species, especially rats, has drastically reduced their range.
The relationship between Coenocorypha snipe and the snipes of the genus Gallinago is uncertain. Coenocorypha is sometimes thought to be a relict taxon of an ancient lineage;[2] however, insufficient research has been done to prove this. The first specimen was collected from the Auckland Islands during the voyage of HMS Erebus and HMS Terror and was described by George Gray in 1845. Ten years later he assigned the species to its own genus. With the exception of the Chatham snipe and the Forbes's snipe (described from fossils found in the Chatham Islands) all subsequent New Zealand snipe collected were assigned as subspecies to the original species, known as the New Zealand snipe. Subspecific forms have been described from the Snares, Little Barrier Island, Stewart Island, the Antipodes Islands and Campbell Island.
A morphological study and comparisons of plumage and behaviour led some authors to accept that the Snares Islands, Little Barrier Island and Stewart Island forms were all species instead of subspecies of the Auckland Island snipe, also raising the possibility that the Antipodes Island snipe might be a separate species.[3]
In 1997, a previously unknown form of snipe was discovered on Jacquemart Island off Campbell Island.[4] The Campbell snipe was described as another subspecies in the radiation of New Zealand snipes.[5] Fossil remains of Coenocorypha have also now been discovered on the islands of New Caledonia, Fiji and Norfolk Island.[6][7] Fossil evidence has also shown that the Little Barrier Island form was once widespread across North Island and the Stewart Island form across South Island; both are now extinct.
The austral snipes have long bills and short necks, wings, and tails. Overall they resemble Gallinago snipes, although smaller, stockier, and with relatively shorter bills.[8] They measure from 19–24 cm long, with wingspans of 28–35 cm, and weigh 75–120 g. The smallest species is the Chatham Island snipe. Their plumage is overall brown; most species have a dark eye stripe. The scapulars on the wings are mottled, with some species having white tips.
The austral snipes are carnivorous, feeding on invertebrates found by probing in the soil and in compacted vegetation.[8] Feeding is both diurnal and nocturnal, with most hunting occurring at night and in the early morning. Bouts of feeding are characterised by continuous probing the soil with the full length of the bill. The ground is covered systematically, with about 18 holes for every 100 cm2 of soil. Prey is presumably detected by touch and possibly by Herbst's corpuscles,[8] clusters of cells that can detect changes in pressure and have been shown to be used by other shorebirds to detect prey.[9] Smaller prey is swallowed with the bill still probed, as the mandibles are flexible and the prey can be manipulated in the soil. Larger prey items are removed from the soil for easier manipulating and swallowing. The most common prey items taken include earthworms, amphipods, beetle adults and larvae and the pupae of other insects.