2018 Sooty Shearwater Update

RuaDog
Rua the seabird dog looking north to Wakaterepapanui and Takapourewa. Photo: Jo Sim

It was another odd breeding season for the sooties. For our first burrow check in early December 2017, we were joined by Jo Sim, Brook Mells and seabird specialist Rua. The southern colony had 23 active burrows, and the sniffer team found two new small colonies of 7 burrows in all, 5 of which were confirmed to contain sooty shearwater. None of the hoped-for smaller petrels were found despite a comprehensive look over the island (Jo recorded the search track with her GPS and plotted it for us). Later we moved the less active of the two petrel speaker set-ups, with flutterer decoys, to a new site reminiscent in aspect of the colony on Long Is., and looking out to where flutterers feed and raft up at times. Flutterer visits have since been recorded on camera, scattered throughout the winter. There appears to be no nesting.

All or most of the sooties were present in January 2018, and by February the main colony held 11 chicks and 1-2 adults. In mid-April 2018, the last check before fledging, there were only 4 chicks; these are presumed to have gone on and fledged. There had also been one killed at the burrow. Only feathers were left and it looked very much like a falcon kill (Richard Cuthbert in his book Seabirds Beyond The Mountain Crest records falcon taking Hutton’s shearwater at the burrow). There was also a dead, partly feathered, chick at one of the outlying colonies, out of the burrow and very early to be so. Perhaps this indicates that the adults were not getting enough food at sea and gave up on the chicks, prompting one at least to attempt to fledge early.

I found it very worthwhile to get some canine input to our seabird effort. The sooties may always be difficult as they are elsewhere in the area, and it’s now clearer that we don’t have a decent, undetected colony of fluttering shearwater, fairy prion or diving petrel. We continue to ponder how to get one of those up and running.

2017 Sooty Season

After last season’s good result, it was looking very promising in January 2017 too. A record 25 burrows were active, but by February this had dwindled to five. Come mid-late April the colony was deserted, a total failure for the season. We saw nothing untoward at the colony during the season- little or no weka activity, no disturbance, no carnage.

Graeme Taylor at DOC says the sooty season elsewhere was average, with 40-50% of active burrows fledging a chick. He says we need to look closer to home than some at-sea event which might have affected all sites. In contrast, the fluttering shearwater colonies on Mana (communicated by Helen Gummer) and Maud (Biz Bell in the March 2017 Birds New Zealand magazine) had poor results, most likely due to burrows being flooded in heavy rain. Puangiangi also had at least a couple of deluges during the generally acknowledged miserable summer, and despite the excellent drainage at the colony, the chicks may have drowned or died of hypothermia.