Figure 5. from the paper which presents vulnerability of seabirds to marine heatwaves (MHWs) is related to the spatial overlap/proximity of the event to breeding and foraging areas, and to the duration of the temporal overlap. Vulnerability is indicated by warmer colours, and the dashed lines are representative of equiva- lent vulnerability. For example, an extended MHW with low spatial overlap will have a similar impact to a brief MHW that has high overlap

Eric J. Woehler (Australasian Seabird Group, Hobart, Tasmania, Australia) and Alistair J. Hobday have published open access in the journal Marine Ecology Progress Series, on how a seabird’s life experience could play a role in moderating the effects of marine heatwaves.

The paper’s abstract follows,

“Marine heatwaves (MHWs) are periods of anomalously warm water associated with changes in ocean structure, based on the horizontal advection of water masses and atmospheric exchange of heat. The longest MHWs persist for many months, and dramatic effects on marine life have been reported from around the world. As top-order predators, seabirds are particularly sensitive to MHWs, with high levels of mortality associated with some events, but not with others. Thus, prediction of impacts is not straightforward, as mortality is not linearly related to simple measures of MHW intensity, persistence, and areal coverage. We describe biological responses expected for seabirds, based on demographic parameters and the geographic proximity and phenological timing of MHWs with respect to seabirds. The expected interactions between seabirds and MHWs will be complex (with some responses likely to be unpredictable) and will extend over broad spatial and temporal scales. The spatial proximity of anomalous marine conditions to breeding colonies, their overlap with foraging areas, and the degree to which MHWs coincide with pre-breeding and breeding seasons presently generate the greatest pressures on seabird populations. We posit that area-restricted seabird species, in terms of movement and breeding strategies, are at greater risk from MHWs, but that non-linear effects complicate prediction. The impacts of MHWs on seabirds may be mediated by their life history strategies.”

Reference: 

Woehler, E.J., Hobday, A.J. 2023. Impacts of marine heatwaves may be mediated by seabird life history strategies. Marine Ecology Progress Series. https://doi.org/10.3354/meps14333

25 August 2023

Mouse-infested Sand Island, with smaller mouse-free Eastern Island upper right, photograph by Jon Brack, USFWS

The Midway Seabird Protection Project aimed to eradicate House Mice Mus musculus that have taken to attacking albatrosses on Sand Island, the larger of the two islands that make up USA’s Midway Atoll in the North Pacific.

“Using a new hopper [filled via an excavator] specially constructed for this project, we safely and efficiently filled the bucket while reducing risk to crew and equipment. Affectionately called Dennis and standing roughly 10-feet [three-metres] tall, the hopper is made of heavy steel and able to stand securely despite the helicopter’s strong downwash”, photograph by Jon Brack, USFWS

Aerial bait applications were completed in July, but subsequently mice have been found to be still present, as recently reported on the Facebook page of the Pacific Islands: U.S. Fish and Wildlife Service.

“In 2015 attacks by invasive mice on albatross at Midway Atoll spurred the U.S. Fish and Wildlife Service and our partners working in Papahānaumokuākea Marine National Monument to initiate the Midway Seabird Protection Project, with a goal to eradicate non-native mice from Sand Island. After years of planning and preparation with top rodent control experts from the U.S. and internationally, the project was implemented this year.

However, after safely and effectively completing bait applications across Sand Island this summer, mice are still present in many areas of the island, and a root cause is not immediately evident.

We are ceasing current eradication efforts and transitioning to continue to care for native species and gathering data to help inform this project and similar projects around the world. Learn more about the project implementation, where we are now with the project, and [find] upcoming updates here.”

Evidence of mouse attacks on Midway’s Laysan Albatrosses, from USFWS

The project reports in its latest update, dated 15 August:

“There are theories, and questions, as to why mice persist on Sand Island. As the team transitions to a Mitigation and Learning Phase, we will continue to gather data to try to find answers. Environmental Monitoring, begun before the application of any bait and continuing throughout the project, can help us understand conditions on the ground. Additional studies can provide knowledge of Sand Island mouse foraging behaviors and food preferences, habitat anomalies, factors of weather and bait, and more. We will also continue to monitor the native wildlife for impacts from mice and take efforts to minimize predation on seabirds when we find it is occurring. The outcome of every rodent eradication effort is uncertain, and every project is an opportunity to learn more about rodents, rodent behavior, toxicants, mitigation of risk to non-target species, and other factors that can influence future restoration projects. Lessons learned on Midway will help inform this project and similar projects around the world”.

The Midway Atoll failure follows that of the Gough Island Restoration Project that failed to eradicate House Mice that also attack that island’s albatrosses (and other seabirds) in 2021.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 24 August 2023

Monitoring the population of Northern Royal Albatrosses (pictured) was one area of focus for the research on New Zealand's Chatham Islands. Photograph by David Brooks

A collection of reports on albatross research conducted on the Chatham Islands has been published by New Zealand’s Department of Conservation.

The Publications:

Motuhara seabird research field trip December 2022 (PDF, 182K)

Trail-camera assessment of the fates of Northern Royal Albatross and Northern Buller’s Mollymawk chicks: 2021 breeding season, Motuhara (PDF, 3,132K)

POP2022-05 Northern Buller’s albatross GLS tracking and comparison with Southern Buller’s albatross (PDF, 5,392K)

POP2022-06 Northern Royal Albatross tracking from Motuhara, Chatham Islands, and Taiaroa Head in 2021 (1,364K) 

A summary of each report follows:

“The field work has been undertaken on Motuhara Island, a privately owned island east of Chatham Island with some of the most significant albatross colonies in New Zealand. Mike Bell (Toroa Consulting Ltd) visited the colony in December 2022 to collect tracking tags of northern Buller’s albatross/mollymawk (Thalassarche bulleri platei), download trail camera footage from cameras left out over the previous 12 months, carry out banding of birds for demographic studies and conduct counts of albatrosses and northern giant petrels (Macronectes halli).

The trail camera footage from 2021 for northern royal albatross (Diomedea sanfordi) and northern Buller’s albatross was analysed by Peter Frost (Science Support Services). This was looking at breeding success at monitored nests, timing and causes of nest failures, activity levels across the daily cycle to inform aerial survey techniques and other observations relevant to the behaviour of the birds across the nesting cycle. Dates of departure of chicks are provided. Climate related issues on the colony are assessed in the report.

Global location sensing tags (GLS) were applied to northern Buller’s albatross as well as southern Buller’s albatross (Thalassarche bulleri) on the Snares Island (Tini Heke). Johannes Fischer has analysed the tracking datasets (n=69 from northerns and n=28 from southerns) to show patterns of annual movements, migration routes and core foraging zones both within the New Zealand EEZ and the high seas and when the birds reach South American waters off Chile and Peru. There are temporal differences in the timing of breeding with a four month difference in peak breeding: northerns departing earlier and returning earlier than southerns, reducing spatial and temporal overlap in their foraging ranges here and off South America. Northerns largely remain north and east of the Chatham Rise whereas southerns are common off southern and western South Island, and off Otago and Canterbury. Some birds reach the seas off Australia.

The satellite tracking of northern royal albatross in 2021 is reported by Samhita Bose. This species had tags applied on Motuhara and the birds stayed exclusively within the New Zealand EEZ during chick rearing. After breeding failure or at the end of the season the birds migrated to the seas off western and eastern South America (Chile, Patagonia and Argentina). Issues with the loss of aerials on tags on some tags were identified with this project. Also a pair of northern royals and their chick from Taiaroa Head were tracked in 2021 and the results presented in this report. The male from this pair made the only visit to the Tasman Sea of the 33 birds involved in this study.”

Publication information

Bell, M. 2023. Motuhara seabird research: field trip report December 2022. Report prepared by Toroa Consulting Limited for the Conservation Services Programme, Department of Conservation. 4 p.  

Frost, P., Bell, M., Taylor, G. 2023.  Trail-camera assessment of the fates of Northern Royal Albatross and Northern Buller’s Mollymawk chicks: 2021 breeding season, Motuhara. Report prepared for the Conservation Services Programme, Department of Conservation. 25 p. 

Bose, S., Bell, M., Taylor, G. 2023.  Northern Royal Albatross tracking from Motuhara, Chatham Islands, and Taiaroa Head in 2021. POP2022-06 final report prepared for the Conservation Services Programme, Department of Conservation. 9 p.  

Fischer, J.H., Bell, M., Frost, P., Sagar, P.M., Thompson, D.R, Middlemiss, K.L., Debski, I., Taylor, G. 2023. Year-round GLS tracking of Northern Buller’s albatross and comparison with Southern Buller’s albatross. POP2022-05 final report prepared for the Conservation Services Programme, Department of Conservation. 16 p.

23 August 2023

Tracks from four different Westland Petrel adults across the annual cycle (two males and two females)

A news article on a study of the ACAP-listed and globally Endangered Westland Petrel Procellaria westlandica, endemic to New Zealand, follows.

“A Department of Conservation team, with field work led by Westport based biodiversity ranger, Kate Simister, has been funded to conduct three years of research into Westland petrels / tāiko. The funding comes from the Conservation Services Programme, which monitors the impact of commercial fishing on protected species, studies species populations and looks at ways to mitigate bycatch.

The new funding has allowed the work programme to expand to cover a range of new projects not previously attempted with this species. These include:

1.      Understanding burrow occupancy rates in this species to determine how burrow mapping and nest counts can be related to numbers of breeding pairs. In particular how the status of apparent non-breeding birds occupying nest sites changes over time (e.g. are these pairs skipping breeding attempts, failed breeders or do these birds lack a partner?)

2.      Investigating the diving behaviour of Westland petrels using time-depth records to determine their risk profile from fisheries methods such as surface and bottom long-lines.

3.      Carry out multi-year tracking of adult birds using Global Location Sensing tags to determine extent of time spent within the New Zealand EEZ and elsewhere in the Southern Hemisphere.

4.      Track juvenile birds to determine if they migrate to seas beyond New Zealand.

5.      Testing of different tag attachment methods for GPS or Argos passive integrated transponder tags.

The study, currently in the third year of field work and the winter breeding season of tāiko, has recently shared a progress report. The report includes some fascinating early findings and when, complete, will provide extensive data for further analysis through an MSc student programme and new scientific papers.

Findings include dive depth and foraging locations as well as their migration to South America.

For the detail, methodology and early findings, the interim report is available here.”

A Westland Petrel in flight, photograph by Raja Stephenson

Text from the website of the West Coast Penguin Trust.

22 August 2023