New bird species are added to the New Zealand list at a rate of at least five per decade. In most cases these are lone individuals that have blown off course (mainly across the Tasman Sea), or migratory species that have apparently ‘got in with the wrong crowd’, and ended up in our corner of the globe. In the last decade, accepted new species records for New Zealand have included Australian reed warbler (2004), great shearwater and streaked shearwater (both in 2006), straw-necked ibis (2009), Pacific gull (2010) and buff-breasted sandpiper (2014). Three of these species breed in Australia, and the three others are long-distance migrants that had all been confirmed in Australia before they were reported (or accepted) in New Zealand.

Most of these new species were found and identified by experienced local bird-watchers. Finding a new species for the country is the holy grail for many bird-watchers, and is part of their motivation for heading outdoors and being observant. However, knowledgeable bird-watchers are thin on the ground in New Zealand, and it is likely that many vagrant birds (including potential new species records) go undetected, unrecognised or unreported.

Serendipity – otherwise known as good luck – plays a part in many discoveries of ‘first records’ for New Zealand, and was certainly involved in the latest addition. Satoshi Kakishima and Tomoe Morimoto are Japanese bird-watchers who made their first visit to New Zealand, a week-long holiday, in September 2014. A highlight of their visit was 2 days on Stewart Island, based at the only settlement of Half Moon Bay. On the morning of 27 September, they were walking to Golden Bay to catch the ferry to Ulva Island, when they saw an unusual bird near Traill Park. They recognised it as being a species of woodswallow, and realised that this was unusual for New Zealand. Fortunately they were able to take three photographs during the brief time that the bird was in view.

When first seen, the bird was perched on an overhead power-line, then it moved to a harakeke/flax flower stalk before flying across the road to land and catch an earthworm then flying out of sight. Satoshi and Tomoe returned to the site two more times (on the way back from Ulva Island that afternoon, plus Tomoe returned the following morning), but the bird was not seen again.

On the evening of 27 September, Satoshi and Tomoe made contact with Invercargill-based bird-watcher Phil Rhodes after finding his contact details on the Birds New Zealand website. Phil is the regional recorder for the Southland Branch of Birds New Zealand; he confirmed the significance of what they had seen, and identified the bird as a dusky woodswallow. The dusky woodswallow is one of two dark-plumaged woodswallow species found in Australia. It differs from the otherwise similar little woodswallow in having a bold white stripe on the leading edge of the outer wing – a feature prominent in the Stewart Island images.

Satoshi Kakishima and Tomoe Morimoto submitted their photographs and notes from their encounter to the Birds New Zealand Records Appraisal Committee (RAC). The terms of reference for the RAC require new species records for New Zealand to be accepted by all five members – and I am pleased to report that this standard was met, and that dusky woodswallow is now officially recognised as occurring in New Zealand.

Dusky woodswallows are common summer migrants to south-eastern Australia, including Tasmania, with these birds presumed to move to Queensland and northern New South Wales (where there are also resident populations) in winter. The bird seen on Stewart Island on 27 September matches the typical timing of southward migration to Tasmania, and it is likely that this bird got blown off course while migrating across Bass Strait.

It is very likely that dusky woodswallows have reached New Zealand previously, but have not met all the requirements of being detected, recognised, submitted and accepted as valid sightings. On my first visit to the Snares Islands in December 1982, I travelled down on a fishing boat skippered by the late Murray Schofield. Murray was a former chief ranger in Fiordland National Park, as well as a long-serving Lands & Survey ranger on Stewart Island. He was both knowledgeable and observant of the birds that he encountered when fishing. The Snares Islands (about 100 km south of Stewart Island) are a tiny speck of land in the middle of a large ocean, and have an impressively long list of vagrant bird species that have taken refuge there. Murray was delighted to be host to a keen bird-watcher, and provided me a list of mouth-watering rarities that he had seen while fishing or when moored in Ho Ho Bay over the previous two years. Among these were two dusky woodswallows that he observed hawking insects and perched on exposed branches above a penguin colony in Ho Ho Bay during 10-13 October 1982. But with no photographs and no description of the birds recorded at the time, we realised that there was little point in seeking official acceptance for the record.

I thank Satoshi Kakishima and Tomoe Morimoto for reporting their sighting promptly, submitting an Unusual Bird Report to the Records Appraisal Committee, and agreeing to the acceptance of their sighting being reported in this Te Papa blog. A provisional dusky woodswallow page was published on the New Zealand Birds Online website on 7 October. The page included the caveat “The dusky woodswallow has yet to be accepted on the New Zealand list, pending assessment of a submitted Unusual Bird Report of a single bird seen and photographed on Stewart Island in late September 2014. This page will be updated when the Birds New Zealand Records Appraisal Committee has reached a decision”. This caveat has now been removed. Congratulations Satoshi and Tomoe!

Click here to hear a Radio New Zealand interview about the discovery.

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