Teamwork during a Te Papa funded charter trip in the Hauraki Gulf got us a step closer in the hunt for the breeding grounds of the recently rediscovered New Zealand Storm-Petrel (Pelaeornis maoriana). The search team included Te Papa researcher Jean-Claude Stahl, Chris Gaskin who is part of the New Zealand storm-petrel research group, and Brett Rathe from Assassin Fishing Charters, all seasoned storm-petrel chasers. Also joining the trip were Dylan Owen from the National Library, and Jacinda Woolly, a trainee ranger with the Auckland Council Parks staff, who was to be dropped off on Burgess Island to participate in petrel studies ashore.
The date of the trip (20 February) was chosen to maximize the chances of success. It was estimated to fall around the provisional hatching time (back calculated from the latest published sightings in the greater Hauraki Gulf), when foraging trips are at their shortest and many non-breeding birds attend colonies. And it also fell just before new moon, when storm-petrels return ashore just after dark rather than waiting for moonset later at night as they often do during the first quarter. The plan for the day was to zigzag northwards towards Little Barrier, the Mokohinau islands and beyond, before returning to just offshore of one or both island groups for observations at dusk, when birds were expected to concentrate off potential breeding sites. The forecast was for mainly fine weather with a light to moderate NNE to NNW wind, although some heavy showers were announced for the afternoon.
These and many previous observations around the Mokohinaus had given some hope that the species breeds somewhere in this island group. However none were seen when we were back in the vicinity of the Mokohinaus at dusk, slowly cruising from north-east of Fanal island to the stacks south of Burgess Island then to Groper Rock. The total absence of birds there at the optimal time of day and breeding season does not bode well for the chances of a major breeding site being located in this island group.
Although negative results can be crucial pieces of information in science (there are several reputed journals of negative results), they are ususally not the glamorous outcomes sought for by researchers. As a last throw of the dice, the team decided to head to another station off Little Barrier Island later in the evening. There the first New Zealand storm-petrel was circling around the boat in a matter of minutes, and up to six possibly seven were attracted overall, one of which was caught and banded by Sarah Wells and Chris Gaskin, adding to the NZSP research group’s tally for this season. This location was in the same general area where a bird had previously flown on board of a fishing boat anchored for the night off the island. In Jean-Claude’s opinion, the activity there late in the day looked more what was to be expected off a petrel colony, and makes Little Barrier the best prospect so far for breeding sites of one of our most enigmatic birds. This however comes with a catch (as it always does): finding nests of a swallow-sized nocturnal bird in the formidable cliffs and ravines of Little Barrier will not be a picnic.