Black-winged Petrel ashore

Terence O’Dwyer (Conservation and Restoration Science, Department of Planning and Environment, New South Wales, Australia) and colleagues have published in the journal Bird Conservation International on breeding recovery of the Black-winged Petrel Pterodroma nigripennis on Australia’s World Heritage Lord Howe Island after the removal of introduced Ship or Black Rats Rattus rattus.

The paper’s abstract follows:

“In 2019, a Rodent Eradication Project (REP) was implemented on World Heritage listed Lord Howe Island, Australia. Among the species expected to benefit was a burrow-nesting seabird, the Black-winged Petrel Pterodroma nigripennis.  Prior to the REP, we assessed causes of Black-winged Petrel nest failure using surveillance cameras. We also measured breeding success before and after the REP and investigated emerging pressures on breeding success from other native species. In 2017, ship rats Rattus rattus were a major cause of Black-winged Petrel nest failure, and breeding success was as low as 2.5%, compared to 47.5% on rodent-free Phillip Island (Norfolk Island Group). In 2020, in the absence of rodents, breeding success on Lord Howe Island increased dramatically to 67% and remained high (50%) in 2021. This result suggests that reproductive output of small seabirds has been heavily supressed by rodents on Lord Howe Island for decades. A subsequent increase in the population of a predatory endemic rail, the Lord Howe Woodhen Hypotaenida sylvestris, combined with burrow competition from Little Shearwaters Puffinus assimilis, indicated that initial high breeding success may not be sustained.  However, the surge in successful breeding of Black-winged Petrels is likely to result in a significant increase in fledgling numbers and the recruitment of hundreds of additional birds each year. Given the important role of petrels in global nutrient cycling, and their positive influence on island biodiversity, their expansion should benefit the ecological restoration of Lord Howe Island.”

With thanks to Sandy Bartle.

Reference:

O’Dwyer, T., Carlile, N., O’Neill, L & Halpin, LR 2022.  Changing fortunes of the Black-winged Petrel Pterodroma nigripennis following the Lord Howe Island Rodent Eradication Project - interactions with other recovering species.  Bird Conservation International doi.org/10.1017/S0959270922000132.

John Cooper, ACAP News Correspondent, 30 August 2022

The CSP's Annual Plan for 2022/23 includes population monitoring of the ACAP-listed Black Petrel (pictured); photograph by Kirk Zufelt

New Zealand’s Conservation Services Programme (CSP) has released its 2022/23 Annual Plan. The CSP operates under the administration of the Department of Conservation with the vision that, “commercial fishing is undertaken in a manner that does not compromise the protection and recovery of protected species in New Zealand fisheries waters”.

The plan provides a comprehensive summary of upcoming and ongoing research projects, their objectives and expected costs. It is divided into three focus areas:

• Interaction Projects (section 2): the Observer Programme and seabird identification programmes.
• Population Projects (section 3): a number of population and demographic studies of albatrosses endemic to New Zealand, monitoring of the Black Petrel and Flesh-footed Shearwater, and research into foraging and diving habits of the Westland Petrel.
• Mitigation Projects (section 4): the Protected Species Liaison Project Officer Programme, the use and effectiveness of various mitigation measures and a project focussed on understanding drivers and barriers to the implementation of mitigation measures by small vessel bottom longline vessels.

The 2022/23 Annual Plan is available at the Department of Conservation’s website, or download here.

Posted 29 August 2022

The G68 Team (Left to Right): Lucy Dorman, Joyfull Ntobeko Gaju, Philani Siyabonga Ngcobo, Sibusiso Maduna, Rebekah Goodwill, Mphumzi Brooklyn Zilindile, Eddy Mfezeko Xaki, Khuliso Collen Maphaha, Mayembe Kapenda; photograph courtesy of Antarctic Legacy of South Africa

The South African National Antarctic Programme (SANAP) has announced the 68^th Gough Island overwintering team (G68) has departed to Gough Island to continue long-term scientific programmes. 

Meteorologists will maintain meteorological records for the South African Weather Service (SAWS). This remote weather station has been manned and providing data for forecasting and research on a daily basis since 1956. 

Seabird monitoring by the UK’s Gough Island Restoration Programme (GIRP) will also continue. The introduction of House Mice to the island in the early 19^th century has devastated some local seabird populations (including ACAP-listed species) which have become a source of food for these small yet resourceful creatures. GIRP’s ambitious objective is to eradicate House Mice from the island and prevent the extinction of seabird species affected by the invasive mice, such as the Critically Endangered Tristan Albatross Diomedea dabbenena. The project suffered a setback earlier this year when footage of a mouse was captured by a camera trap, dashing hopes that the eradication attempt had been a success. Further mice were then discovered on the island. Efforts are now underway to understand what might have enabled mice to survive the eradication operation.

The team departed on 20 August 2022 aboard the South African Antarctic research and supply vessel the S.A. Agulhas II which briefly stopped at Tristan da Cunha to offload passengers and cargo before making the onward journey to Gough. G68 will be stationed on Gough Island for approximately 13 months, replacing the G67 team members who are close to finishing their stint. 

Posted 26 August 2022

A Tristan Albatross chick attacked by House Mice on Gough Island, photograph by Kate Lawrence

Araceli Samaniego (Manaaki Whenua – Landcare Research, Auckland, New Zealand) and colleagues have published open access in the journal Wildlife Research on the possible role of alien slugs in the failure of the 2021 attempt to eradicate the albatross- and petrel-killing House Mice of Gough Island.

The paper’s abstract follows:

“Context: House mice (Mus musculus) are the main drivers of biodiversity declines on Gough Island (6500 ha; 40°21′S, 009°53′W), central South Atlantic. A mouse eradication operation was planned, the largest global attempt targeting only this species. Understanding and managing challenges of operating at such scales are crucial for maximising the chance of eradication success. The Gough Island mouse eradication attempt was implemented between June and August 2021, after years of planning and trials. We expected poor weather and negligible non-target bait consumption.

Aims: We aimed to assess the impact of expected and unexpected challenges faced during the eradication operation on Gough Island, namely poor weather and rapid bait disappearance.

Methods: We set up bait degradation plots across the primary habitats to monitor the impact of expected heavy rain on bait pellets. In contrast, bait availability monitoring and slug laboratory trials were set up ad hoc in response to unexpected observations of high bait consumption by invasive slugs in the lowlands, where both slugs and mice are more abundant.

Key results: Bait degradation rates were very different between the highlands and the lowlands, with bait in the highlands lasting about six times longer, despite bait pellets receiving more precipitation and the highlands being persistently under cloud. Bait availability in the lowlands dropped by >80% within a few days of the second and third bait application, down to critically low levels (∼2 kg ha⁻¹). Importantly, mouse activity was negligible by this time. Non-native slugs appeared to be the main cause of such a sudden drop in rodent bait availability.

Conclusions: The expected rainy weather was not a significant direct cause of bait degradation in the short term. In contrast, the unexpected slug interference, overlooked in earlier planning trials, resulted in major adjustments of the baiting strategy. Indeed, the rapid bait disappearance in the lowlands triggered the third bait application over this area, at a higher rate. This was not enough, as mice are still present.

Implications: This is the first report of slug interference during aerial rodent eradications. Our results illustrate how interference by non-target species could affect future pest eradications using baits and should, as far as possible, be assessed early during planning.”

Reference:

Samaniego A., Jolley W. & McClelland, P. 2022.  A lesson for planning rodent eradications: interference of invasive slugs during the Gough Island mouse eradication attempt in 2021.  Wildlife ResearchWildlife Research  doi.org/10.1071/WR22024..

John Cooper, ACAP News Correspondent, 25 August 2022, updated 26 August 2022