ACAP Latest News has reported regularly on progress with attempts to eradicate rodents by dropping poison bait from helicopters on South Georgia (Islas Georgias del Sur)* in the South Atlantic (click here).

A Team Rat helicopter with slung bait bucket flies over the island

The third and final phase of bait dropping is now underway, in the southern part (35% and 360 km²) of the island.  Rob Webster, Deputy Project Director of the South Georgia Habitat Restoration Project reported to ACAP this week of progress to date:

“We have passed the 50% mark - to be more precise, we sowed 33 pods of bait, which equates to a bit more than 10 tonnes of bait pellets spread today on the Barff Peninsula and takes us to 52% of Phase 3 baiting completed.  We are now within about 6 hours of work from finishing that baiting zone, the largest of the Phase 3 zones - at that point we should have eradicated rats from all the land from the entrance to Cumberland Bay down to the Ross and Hindle Glaciers at the head of Royal Bay.”

South Georgia (Islas Georgias del Sur)* showing the three baiting regions; top red Phase 2, Middle green Phase 1, bottom red , Phase 3

Daily e-mails received by ACAP from the island report that weather conditions have halted flying on a number of days this month.  In addition, gale-force winds made one of the three helicopters unserviceable so “Team Rat” has had its setbacks.

Related news from the South Georgia Heritage Trust is of the finding of the first South Georgia Pipit Anthus antarcticus nest, containing five chicks, in an area previously cleared of rodents in May 2013 as part of Phase 2 of the project.  The return of pipits to the main island from their refugia on offshore islets free of rats is suggestive that burrowing petrels, including the ACAP-listed White-chinned Petrel Procellaria aequinoctialis, will also fare better in the absence of rats.

The pipit nest - in the absence of rats

Click here to access Team Rat’s latest newsletter (Project News, No. 24 of February 2015) and here to read the latest on the eradication of introduced Reindeer Rangifer tarandus on the island.  More conservation news is in the latest South Georgia Newsletter.

With thanks to Keith Springer and Rob Webster for information.

John Cooper, ACAP Information Officer, 25 February 2015

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur y Islas Sandwich del Sur) and the surrounding maritime areas.

Yuna Kim (Department of Biological Sciences, Macquarie University, Sydney, Australia) has been awarded her PhD for a study of the Vulnerable Gould’s or White-winged Petrel Pterodroma leucoptera on Cabbage Tree Island off New South Wales, Australia.  Techniques tested and used in her study of a burrow-nesting gadfly petrel are considered to have relevance to similar studies conducted on the five ACAP-listed Procellaria petrels, which also breed in burrows.

Yuna Kim on the top of Cabbage Tree Island

Her thesis abstract follows:

“Many seabirds experience threats in their environment when breeding and foraging in the highly variable marine ecosystems. Understanding breeding and foraging ecology is crucial to conserve threatened species.  The research presented in this thesis aimed to investigate the foraging ecology of Gould’s Petrel (Pterodroma leucoptera) on Cabbage Tree Island (CTI), New South Wales (NSW), Australia, to provide a knowledge base to inform the future conservation and management of this threatened species.  First, I validated my methods to ensure they were ethical and effective.  I found no detectable negative impact of using tracking devices on adult mass changes and associated chick growth and breeding success.  Second, I tested the reliability and practicality of four techniques (trapping adults, measuring mass change in chicks, examining images from infrared cameras and analysing temperature data from geolocators) to monitor nest attendance rates.  I concluded that temperature loggers featured within geolocators could be used to monitor nest attendance effectively.  Third, I explored the relationships between body mass, incubation shift duration and nest desertion and concluded that incubation success was limited by the condition of birds at the start of the shift and their tenacity to remain until relieved by their partner.  Lastly, but most importantly, I identified the core foraging areas of Gould’s Petrels during the breeding season, which were previously unknown.  In addition, I confirmed that Gould’s Petrels adopted a dual foraging strategy by measuring foraging trip durations and distances during the breeding season.  Examination of regurgitated stomach contents suggested diversity and variation in diet of the Gould’s Petrel, showing that it is an opportunistic forager, which is important to cope with variable environment.  These findings are discussed in relation to management of issues with a view to improving conservation strategies for this threatened species and, potentially, other small pelagic seabirds.” 

Gould's Petrel with a leg-mounted geolocator

Gould's Petrel chick in the hand

In a preface to her thesis Yuna Kim concludes:

“I believe that the outcomes of my thesis contribute to the science base for identifying and mitigating threats to small seabirds.  I endeavour to contribute to an international collaborative research program aimed at characterising seabird hotspots and the identification of links between this community and the wider food chain to understand marine ecosystems under stress from overexploitation and global climate change.”

With thanks to Yuna Kim for information and photographs.

References:

Kim, Y. 2015.  Breeding and foraging ecology of the threatened Gould’s Petrel, Pterodroma leucoptera.  PhD thesis.  Sydney: Macquarie University.  221 pp.

Kim, Y., Priddel, D., Carlile, N., Merrick, J.R. & Harcourt, R. 2014.  Do tracking tags impede breeding performance in the threatened Gould’s Petrel Pterodroma leucoptera?  Marine Ornithology 42: 63-68.

Priddel, D., Carlile, N., Portelli, D., Kim, Y., O’Neill, L., Bretagnolle, V., Ballance, L.T., Phillips, R.A., Pitman, R.L. & Rayner, M.J. in press.  Pelagic distribution of Gould’s Petrel Pterodroma leucoptera: linking shipboard and beached bird sightings with remote tracking data. Emu. 

John Cooper, ACAP Information Officer, 25 February 2015

ACAP Latest News has previously reported a number of times on ongoing efforts to remove introduced Reindeer Rangifer tarandus from South Georgia (Islas Georgias del Sur)* in the South Atlantic with an aerial survey last month confirming that at least 21 animals remained on the island (click here).  News is now in that the alien herbivore may have been finally eradicated from the island with a total of 44 being shot by marksman this year on the Barff Peninsula.  As a consequence vegetation is recovering in the absence of Reindeer to the eventual advantage of burrowing petrels, including the ACAP-listed White-chinned Petrel Procellaria aequinoctialis.

Reindeer on South Georgia with King Penguins, photograph by Martin Collins

Environment Officer Jennifer Lee’s account is given below.

“Following many years hard work of planning, and two years of field operations, in January two marksmen from the Norwegian Nature Inspectorate (SNO) made one final sweep of the Barff Peninsula in order to locate and shoot any reindeer that remained.

The two SNO marksmen on newly named Ranger Ridge

One of the marksmen searching for any remaining reindeer on the Barff Peninsula. Photograph from SNO

The operation to eradicate reindeer from South Georgia began in 2013.  A combination of herding and ground shooting were used in the Busen area with Sami herders gathering around 1,000 animals and SNO ground shooters removing another 1,000 animals from areas where the terrain meant herding was not possible.  As shooting in the Busen area took less time than anticipated, marksmen were also deployed on the Barff Peninsula where a further 1,555 reindeer were killed.  The following year, a team of six marksmen worked to remove the remaining reindeer on the Barff Peninsula and were successful in shooting 3,140 animals.

In the months since the main cull of the Barff heard took place, field parties and aerial searches had been undertaken to determine how many reindeer remained and where they were located. In January 2015 two of the SNO marksmen returned to conduct a final sweep. Just prior to their arrival HMS Dragon visited the island and identified a group of 21 reindeer close to the tip of the peninsula.  In an incredible feat of efficiency and professionalism, within 6 hours of being deployed to the field, the two marksmen [had] shot these 21 animals and harvested some of the meat ready for collection the next day by staff from KEP.

As expected, in the absence of reindeer, vegetation has started to recover from the severe overgrazing it had been subject to for more than 100 years.  Interestingly, the marksmen were able to use this to their advantage and could often determine where the reindeer were located by looking at the height and composition of the vegetation.  In areas where even a small number of reindeer persisted, the grass was short and cropped whereas the valleys, which had had a year to recover, were lush and thickly vegetated.

Early signs of vegetation recovery now the reindeer have gone. Photograph from SNO

In the subsequent three weeks, the marksmen worked their way south and shot a further 15 animals at Penguin Bay, 5 at the top of Sorling Valley and 3 close to St Andrews Bay.  This brings the total number of reindeer killed on the Barff Peninsula to 4,739, and the total number of reindeer eradicated on South Georgia to over 6,700.  In the coming weeks, eagle eyed field workers and helicopter pilots will continue to search for any signs of reindeer.”

Reference:

Lee, J. 2015.  Clean sweep?  South Georgia Newsletter January 2015.

John Cooper, ACAP Information Officer, 24 February 2015

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur y Islas Sandwich del Sur) and the surrounding maritime areas.

Helen Gummer (Department of Conservation, Wellington, New Zealand) and colleagues have published in the journal Global Ecology and Conservation on successes achieved in bringing back the threatened Chatham Petrel Pterodroma axillaris from the brink.

The paper’s abstract follows:

“Conservation of gadfly petrels, some of the most threatened seabirds, is frequently dependent on long-term research and management.  We review 20 years of a program preventing the extinction of the Chatham petrel (Pterodroma axillaris), a New Zealand endemic once declining due to intense burrow competition from another native seabird. Breeding success in the early 1990s was unsustainably low (10–30%).  Recovery measures started in 1992 when Chatham petrel burrows were converted and artificial entrances blockaded to exclude broad-billed prions (Pachyptila vittata).  Pair and burrow fidelity were enhanced, though prions still posed a threat during Chatham petrel chick-rearing.  Breeding success improved when prions were culled, however a less intensive and contentious solution was to introduce burrow flaps in 2001 which reduced interference from prospecting prions.  Subsequently, breeding success increased to a mean 80% per annum.  Finding burrows, primarily using radio-telemetry, increased those under management from eight in 1990 to 217 in 2010 when spotlight surveys indicated 72% of juvenile birds had fledged from managed burrows.  Chick translocations to two other islands and increasing population size (from 200–400 birds in 1990 to an estimated 1400 birds by 2010) has improved the species IUCN status from Critically Endangered in 1990 to Endangered in 2013."

Chatham Petrel, photograph by Don Merton

Graeme Taylor holds a Chatham Petrel chick, photograph by Helen Gummer

Reference:

Gummer, H., Taylor, G., Wilson, K.-J. & Rayner, M.J. 2015.  Recovery of the endangered Chatham petrel (Pterodroma axillaris): A review of conservation management techniques from 1990 to 2010.  Global Ecology and Conservation 3: 310-323.

NOTE:  Starting with this item, ACAP Latest News will from time to time report on efforts to conserve gadfly petrels in the genus Pterodroma where it is thought that findings or techniques are relevant to efforts to conserve ACAP-listed species, especially the burrowing petrels of the genus Procellaria.

John Cooper, ACAP Information Officer, 23 February 2015