TOSSI - Bringing back the birds

Something I love about volunteering with TOSSI is finding myself in the back and beyond of Tāwharanui Peninsula – exploring hideaways within the open sanctuary that most visitors miss. A recent tour hosted by Auckland Council park rangers and experienced TOSSI members was an opportunity to discover more about the whenua and witness the outcomes achieved by visionaries.

An intriguing project is the seabird nesting boxes, hidden on a clifftop away from hordes of trail walkers. Seabirds are remarkable beings, spending long periods at sea and then crash-landing into coastal pōhutukawa and dropping to the ground where they dig nesting burrows. Grey-faced petrels and fluttering shearwaters are no longer a common sight on mainland coastal cliffs, preferring to nest on islands where they are protected from rats, stoats and cats.

Monitoring seabirds at night at Tāwharanui.Monitoring seabirds at night at Tāwharanui.

Seabirds have discovered relative safety within Tāwharanui sanctuary and from early autumn onwards they arrive at the site to peruse the latest real estate on offer. Recorded seabird calls project from a nearby sound system to attract and anchor them to the site. After choosing their mate and their home, the birds disappear for several weeks before returning to the nesting boxes to lay a single egg.  The boxes were introduced to accelerate the development of a seabird colony in the sanctuary and they are so comfy, little blue penguins have become uninvited squatters in some of them. There are a few neighbourhood squabbles and even bloody battles between the native species. It is a good sign that some seabirds prefer to do the hard work and dig their own nesting burrows.

TOSSI volunteers, Auckland Council park rangers, tertiary students and Northern New Zealand Seabird Trust members monitor the birds' progress – from nesting to eggs, to chicks, to fledglings. The greatest threat remains predation, with rats, cats and stoats being a serious danger and the determined pests will swim and scamper many kilometres to feed on native birds. An outstanding accomplishment is the nesting of Cook's petrel within the Tāwharanui sanctuary – possibly the only naturally established pair on New Zealand's mainland. Formerly, this small grey and white petrel was only known to breed on Little Barrier, Great Barrier and Codfish Island.

Prior to European settlement the cliffs and coastlines were nesting havens and the wildlife significantly contributed to the delicate balance of coastal ecosystems. Nitrogen and phosphorus-rich guano, produced by millions of seabirds, would have created natural nutrient hot spots and provided essential runoff to native land and sea plants. They would have dug and trampled the soil and deposited nesting materials and seeds. How impressive it would be to see a huge flurry of seabird activity return to Tāwharanui, bringing with it all the benefits of greater biodiversity and restorative balance.

Jackie Russell, TOSSI