The New Zealand travel bubble might have started to much fanfare but for some trans-Tasman travellers it has never applied.
A small shorebird from New Zealand, the double-banded plover, has not only defied travel restrictions, it has defied the laws of migration which generally sees birds travel north in autumn.
The New Zealand waders travel in the opposite direction, from alpine areas on that country’s South Island to Tasmanian shores. From about April to September, Tasmania and coastal areas of the mainland remains the plovers’ winter home.
The plover is a small, elegant species measuring a mere 20 centimetres but as with the other migratory waders, we do not generally get to see it in its full breeding livery. It loses its distinctive parallel black and russet bands across its chest for a more muted brown-grey plumage.
Shorebird species worldwide are under extreme pressure because of the loss of the wetlands they need to feed and breed. The bigger, more dramatic species have been in the news in recent years with the discovery of their remarkable feats of endurance. Satellite tracking of a bar-tailed godwit last spring revealed it had flown non-stop for 12000 kilometres between Alaska and New Zealand.
The doubled-banded plover, however, tends to slip under the radar simply because its migratory exploits are not as dramatic. But the threats to its survival still remain the same as the bigger species.
The long-distance species travelling north are losing habitat in such countries as China and the Koreas when they fly along what is termed the Australasian-East Asian migratory flyway. With the New Zealand plover the problem occurs closer to home, in its breeding range in the Southern Alps. The plovers are rare among waders that breed in the southern hemisphere in that they do not nest exclusively on beaches. Instead they have evolved to nest in the alpine zone, laying eggs in a shallow scrape in pebbles and gravel along mountain streams. Here they fall victim to introduced mammalian predators, including hedgehogs, stoats, cats and rats. Their breeding areas are also becoming overgrown with invasive weeds.
The double-banded plovers, along with Tasmania’s resident pied oystercatchers and red-capped plovers, have long been a bird-watching drawcard on wetlands in the Hobart area when the summer visitors have left. They can sometimes be seen on the sandy shore beneath the Sorell causeway on the Tasman Highway and along the shingle of Ralphs Bay at Lauderdale.
Because of an increasing level of threat, the species has been upgraded in the international Red List of declining birds from least concern to near-threatened.
Birders in Tasmania are monitoring plover numbers carefully. It will be a blow if these New Zealand passport holders continue to decline, especially in the light of the dramatic fall in numbers of the trans-continental migrants.