Scones day on Burgess Island: studying seabirds in New Zealand's Hauraki Gulf

A guest blog by Abe Borker

A starry night of White-faced Storm-petrels.

A starry night of White-faced Storm-petrels.

A stormy day on Burgess Island.

A stormy day on Burgess Island.

All six of the island’s mammals are just keeping dry today; poorly adapted to island life, maybe we’re not meant to be here. The thousands of avian and reptilian vertebrate residents, however, are probably just as happy to have drenching rain and 30 knot gusts as calm sunshine, but it tends to throw a slight kink into our well-oiled seabird research machine. Last night, we checked the radar maps to see a large red/pink (meaning hellish) blob of weather headed our way. To affirm our tough reputation as seabird biologists, we spent a few hours in the rain looking for storm-petrel burrows and their residents but before long we were thoroughly drenched, and our fearless leader Chris declared that the following day would be a “Scones Day” - one bit of kiwi English that needed no translation. Be it offshore islands in California or New Zealand, days like this aren’t fit for much other than baking, staying indoors, editing photos and writing. With any luck, the storm should blow over by the end of today, leaving us with a few nice days for the rest of our trip.

If I look around the bunkhouse, I could be on almost any island’s research station. There are walls littered with various old maps, photos and biological curiosities, a pile of seabird carcasses by the door, many more spread wings and feathers in the entranceway, dilapidated furniture, more battery chargers than I can count, and importantly, lots and lots of high calorie foods. While indoor, it can look a lot like the Farallones, but a far different seabird soundscape emerges when you step outside. Just down the lighthouse path are Fluttering and Little Shearwater burrows deep in the vegetation, and if one walks a little farther, White-faced Storm-Petrels and Black-winged Petrels have turned the ground into swiss cheese. Hobbling around the ground like bizarre Cassin’s Auklets are Common Diving-Petrels. You must be super careful not to accidently step on the grass tussocks that seem alive with calls. There are a few burrows you could lose a leg in, and those belong to the Grey-faced Petrels I’ve yet to see. Lastly, on lower slopes, large burrows belong to the foul smelling, foul sounding Blue Penguins. A really good kiwi seabird biologist already could tell you where I am by species assemblage, but for the rest; we’re camped out on Burgess Island in the Mokohinau Islands.

Measuring growth rates of a White-faced Storm-petrel chick.

Measuring growth rates of a White-faced Storm-petrel chick.

Buller's Shearwaters and Burgess Island lighthouse.

Buller's Shearwaters and Burgess Island lighthouse.

If you’re interested in protecting threatened seabirds, New Zealand is the place to be. Despite it being smaller in area than California, it has over 30 threatened breeding species. Monitoring population trends and evaluating outcomes of conservation actions here is important to saving these species. In fact, some of the most cost-effective actions to protect seabirds in our local marine environment in California depend on protecting breeding habitat halfway around the world. Thankfully, New Zealanders have led the way in island-scale restoration. Burgess Island was one of the first islands in New Zealand to have its rodents removed by the Department of Conservation in 1990, and the island now thrives, rodent free, for over a quarter century. Today these islands support at least 12 breeding species of seabirds (including 7 procellarids!), endemic skinks, geckos and surely even more invertebrate and plant biodiversity than us bird-centric folks realize.

I’m here with five other scientists to investigate how seabirds are faring out here, where they go, and what they do. My own interest is testing acoustic monitoring approaches to measure the diversity and abundance of these remote colonies.  By recording night sounds with small inexpensive acoustic recorders we can identify what species live on islands, estimate their relative abundance and seasonal patterns.  The nights out here are overwhelming as tens of thousands of birds descend and release all sorts of primitive sounds into the night air. By contrast, even at the species-rich Farallon Islands in California, nighttime acoustic activity is generally restricted to four or five species of seabirds. Recordings here might have twice as many species vocalizing over the course of a single night. Both are a far cry from the single species tern colonies I started working in three years ago! Why research the effectiveness of acoustic monitoring out here? For every accessible island like Burgess, there are many more so remote, fragile or dangerous to visit that we don’t know much about the island’s seabirds. Even on Burgess, we work in only a fraction of the seabird breeding habitat for a few months a year. Island scale information on the diversity and abundance of cryptic seabirds is critical to evaluate how effective our conservation and management actions have been. In a country like New Zealand, with so many endangered seabirds, and relatively few people and resources, there’s a strong desire to embrace scalable tools for population monitoring approaches like acoustics.

That night we feasted on mincemeat and sautéed veggies, finishing off with a bread pudding my American taste buds will never fully embrace. Regardless, we finally had a break in the rain and were ready to check out the nighttime visitors. One step out the door and we heard could hear petrels calling overhead. After walking a few hundred meters, we encountered five species of tubenoses! Black-winged Petrels and White-faced Storm-petrels buzzed our heads as we stood on the ridge. My colleagues began “war-whooping”, an improbable but incredibly effective solution to getting a wild bird to land squarely at your feet.  Imagine our luck, when the very first bird was one carrying a valuable geolocator tag carrying a year of data about where the winged wandered had roamed!  After a few hours, we all returned “fully knackered”; too tired even to dream of the exciting week in store and the looming possibility of rediscovering the breeding ground of the elusive New Zealand Storm-petrel.

Abe Borker is a Ph.D. candidate in Ecology and Evolutionary Biology at UCSC.