Jaimie Cleeland was awarded a PhD last year by the University of Tasmania for her study of four species of ACAP-listed albatrosses (Black-browed Thalassarche melanophris, Grey-headed T. chrystostoma, Light-mantled Phoebetria palpebrata and Wandering Diomedea exulans) that breed on Australia's sub-Antarctic Macquarie Island.

The abstract of her thesis follows:

“Understanding the ecological relationships between a species and the environment it inhabits is critical to determining species resilience to environmental change and future population viability. By assessing ecological relationships across multiple species greater insights into species intrinsic adaptations and external environmental factors can be revealed, contributing to a broader understanding of community ecology.

This thesis examines the foraging behaviours and environmental drivers of demographic variability of four albatross species from subantarctic Macquarie Island (black-browed Thalassarche melanophris, grey-headed T. chrystostoma, light-mantled Phoebetria palpebrata and wandering albatrosses Diomedea exulans) to understand the ecological, morphological and life history relationships that influence species resilience to ecological shifts.

Three of the four albatross species that inhabit Macquarie Island exist in small populations of less than 80 breeding pairs (for light-mantled albatross the current breeding population estimate is approximately 2 150 pairs). Consistent monitoring since 1994 shows varied population trends among the species; black-browed and light-mantled albatrosses are increasing, while the grey-headed albatross population remains stable and the wandering albatross population is declining. The decline of Macquarie Island’s wandering albatrosses is attributed to long-line fishing operations, however for the remaining species, population and demographic drivers are unidentified. Aside from the threat to survival presented by fisheries, Macquarie Island albatrosses face climate-driven changes to physical oceanic processes including a southerly shift in frontal positions, intensifying wind patterns and greater variability in sea ice dynamics. For albatrosses, such changes are predicted to alter the structuring of prey resources and influence the energetic costs of foraging, ultimately compromising their capacity to survive and reproduce. At the colony, trends in the reproductive output of Macquarie Island albatrosses may be influenced by severe habitat degradation, including vegetation suppression and landslides, caused by the grazing of invasive rabbits.

Specifically, this thesis aims to: 1) identify important at-sea habitats and vulnerability to climate change in the Southern Ocean 2) understand the indirect impacts of onshore change caused by climate change and invasive species on albatross reproductive output 3) quantify the relative contribution of at-sea (climate change and fisheries) and onshore change (habitat degradation and weather) to demographic variability.

1) Habitat models of residence time from tracking data of all four species (n = 47, 1994-2009) were used to quantify the physical features associated with core foraging areas.  During the breeding season, species overlap was high close to the island, extending north into the Tasman Sea. Conversely, nonbreeding albatrosses showed high variability in habitat use across wide ocean expanses but similarly used productive frontal regions and associated mesoscale eddies. Residence times were linked to moderate wind speeds for all species, suggesting that birds use areas where the aerodynamic performance will be greatest, reflecting morphological adaptations.  Given the core foraging areas identified, and the functional and life history adaptations of each species, it is expected that of the four albatross species breeding on Macquarie Island, black-browed albatross may be more vulnerable to future climate-driven changes to wind patterns in the Southern Ocean and potential latitudinal shifts in the Subantarctic Front;

2) To quantify the influence of invasive European rabbits Oryctolagus cuniculus and extreme weather patterns on the reproductive output of three escarpment nesting albatross species (black-browed, grey-headed, and light-mantled albatrosses) demographic multi-event models were applied to 20 years of mark-recapture data.

High rabbit densities corresponded to reduced breeding propensity of all species, with severe declines observed during periods of highest rabbit numbers. For one species; the black-browed albatross, the combination of extreme rainfall and high rabbit density significantly explained reduced breeding success. These results show the cascading and compounding effects of a successful mammalian invader and extreme weather events on the reproductive output of a community of albatross species, offering compelling support for active management of island ecosystems;

3) The temporal variability in survival, breeding propensity and success was assessed using 20 years of mark-recapture data from four species of Macquarie Island albatrosses. For three species (excluding wandering albatrosses), the influence of oceanic, fisheries and onshore change were investigated using multi-event models to give insight into future population viability. Large-scale climate cycles; the Southern Annular Mode and the El Niño/Southern Oscillation explained significant variability in the survival of all species. For black-browed albatrosses, south-west Atlantic longline and New Zealand trawl fisheries effort described variability in survival.  These findings suggest that managing drivers of negative demographic trends that may be more easily controlled, such as fisheries and habitat degradation, will be a viable option for some species (e.g. black-browed albatrosses) but less effective for others (e.g. light-mantled albatrosses), as opposed to drivers which are not easily mitigated, such as climate change. These findings illustrate the importance of integrating oceanic, fisheries and onshore threatening processes when assessing demographic variability and the development of management policy;

The results of this study suggest that managing sources of negative demographic trends that are more easily controlled, such as fisheries and habitat degradation, as opposed to those which are not; such as climate change, may be a viable option for some species (e.g. blackbrowed albatross) and less effective for others (e.g. light-mantled albatross). Subsequently, this study provides support for evidence-based conservation planning for these populations as well reduces outcome uncertainty of future management actions for other marine predator populations. Furthermore, this study has provided new insights into the ecology of a community of Southern Ocean predators and has broader applications for understanding the responses of multiple sympatric species to multiple environmental stressors.”

Jaimie Cleeland with Light-mantled Albatrosses on Macquarie Island

Click here for details of a publication co-authored by Jaimie Cleeland from her PhD research.

With thanks to Jaimie Cleeland.

Reference:

Cleeland, J.  2017.  Factors that drive demographic change in a community of albatrosses.  PhD thesis.  Hobart: University of Tasmania.  153 pp.

John Cooper, ACAP Information Officer, 10 October 2019

The Midway Seabird Protection Project aims to eradicate introduced House Mice Mus musculus from Sand Island, part of the USA’s Midway Atoll next year.  The operation is scheduled to take place over the month of July near the end of the dry season when the mice are looking for scarce food sources and when bird numbers on the island should be at their lowest (click here to read more and to access the very detailed Final Environmental Assessment and Project Plan).  The mice in recent years have started to attack and kill breeding Black-footed Phoebastria nigripes and Laysan P. immutabilis Albatrosses (click here to access ACAP Latest News postings on Midway’s mice).  “From 2015 to 2017 the number of mouse attacks on seabirds at Midway exploded – growing from a series of isolated attacks to a widespread crisis affecting birds throughout the albatross colony”.

Mouse attack!  A wounded adult Laysan Albatross on Midway Atoll, photograph from the Friends of Midway Atoll National Wildlife Reserve

Bait pellets containing the rodenticide Brodifacoum 25D will be spread across much of the island from helicopters using a specially designed bait hopper; buildings and surrounds will be treated by hand baiting, bait boxes and trapping.  Prior to the start of the project, a mitigation team will attempt to capture some 400 individuals of the Critically Endangered Laysan Duck Anas laysanensis on Sand Island that have been deemed to be at risk to poisoning.  Captive ducks and also globally Vulnerable Bristle-thighed Curlews Numenius tahitiensis and perhaps other shorebirds (which do not breed on Midway) will be kept in aviaries on Sand Island until immediately before the July application period.  They will then be moved to corresponding aviaries or released following wing clipping on nearby mouse-free Eastern Island where they will be kept until monitoring teams deem it safe to release them back on Sand Island.  Few migratory shorebirds are expected to be on Midway in July.  Strict biosecurity procedures already in existence will continue after the bait drop to minimise the chances of mice being reintroduced to the atoll.

One of the partners with the U.S. Fish and Wildlife Service of the Midway Seabird Protection Project is the NGO Island Conservation, which is aiming to raise one million US Dollars towards the cost of the eradication exercise via an Adopt an Albatross campaign (click here).  It has now reported via its Facebook page that due to “generous contributions of our donors and partners” the funding gap is now US$750 000.   Financial support has also come from the Friends of Midway Atoll National Wildlife Reserve (FOMA) which has made US$20 000 available for the construction of the required aviaries as reported on ts Facebook page.

Aviaries under construction on Midway's Sand Island, photograph from the Friends of Midway Atoll National Wildlife Reserve

Next year will be the first year that a World Albatross Day is held, on 19 June, the date the Agreement was signed in Australia.  The chosen inaugural theme is “Eradicating Island Pests”.  ACAP Latest News will follow progress towards next year’s Midway eradication as part of the build up to World Albatross Day.

Reference:

Hamer Environmental L.P. and Planning Solutions, Inc. 2019.  Midway Seabird Protection Project Final Environmental Assessment Sand Island, Midway Atoll, Papahanaumokuakea Marine National Monument.  Honolulu: U.S. Fish and Wildlife Service.  350 pp.

John Cooper, ACAP Information Officer, 09 October 2019

Following an exchange of letters the American Bird Conservancy will participate with ACAP in the inauguration of World Albatross Day on 19 June next year – and in future years.  Mike Parr, President and Clare Nielsen, Vice President, Communications of the American Bird Conservancy have written to ACAP: “We plan to participate by providing social media content to raise awareness of albatrosses and their conservation needs.”

ACAP’s Executive Secretary, Christine Bogle, expressed her pleasure with the development: “I look forward to ACAP working closely with the conservancy to promote the first World Albatross Day in 2020”.  She noted that two threatened ACAP-listed species occurring in Pacific waters, the Critically Endangered Waved Albatross Phoebastria irrorata of Ecuador, and the Vulnerable Pink-footed Shearwater Ardenna creatopus, endemic to Chile, were of especial interest to both organizations.

Hannah Nevins, American Bird Conservancy’s Seabird Program Director, has written to ACAP Latest News: “World Albatross Day is a chance to celebrate one of the most awe-inspiring creatures on this earth.  Albatross link us to the ocean.  The fact that these birds are affected by plastics and other marine debris reminds us that our actions on land affect them and their watery realm.” Following the letter exchange, Hannah has been co-opted to ACAP’s World Albatross Day Intersessional Group, which is chaired by Verónica López from Chile.

Hannah Nevins, Seabird Program Director, American Bird Conservancy

The mission of the ABC, a non-profit organization based in the United States, is to conserve native birds and their habitats throughout the Americas.  Its Seabird Program works to protect seabirds through direct conservation, outreach and policy work.  Albatross conservation is regarded as a priority in the Americas and globally by the conservancy where it can increase awareness and address threats.

With thanks to Verónica López and Hannah Nevins.

John Cooper, ACAP Information Officer, 08 October 2019

A feral cat Felis catus was photographed and videoed feeding from the corpse of a White-capped Albatross Thalassarche steadi chick (Near Threatened) on its nest at South-West Cape on New Zealand’s Auckland Island on 25 and 26 August this year (click here).

A feral cat feeds from a White-capped Albatross chick on Auckland Island, August 2019;  photographs by Department of Conservation o Te Papa Atawhai

Stephen Horn, Project Manager - Maukahuka - Pest free Auckland Island, has written to ACAP Latest News over the incident:

“The cat was first seen basking in the sun about 5 to 10 metres from the dead bird and the photographers waited for a couple of hours before it strolled down the hill and resumed feeding on it and they got the photos.  It was still there the next day.  Unable to say if it was just scavenging or had killed it.  The neck muscles had all been eaten and it was feeding on the back, no damage to the breast at that stage.”

There appear to be few records of feral cats attacking albatrosses (and in this case the cat may have come across a corpse rather than acted as a predator).  A feral cat was seen feeding on the corpse of a Light-mantled Sooty Albatross Phoebastria palpebrata chick on (now cat-free) Marion Island in 1981.  Cats have been thought to have killed a number of Laysan Albatross Phoebastria immutabilis chicks on the Hawaiian island of Kauai in 2015 (click here), although definite evidence of predation appears to be lacking.  A more exhaustive literature search may turn up more records from localities where albatrosses and feral cats co-exist – or once did.

Field work continues on Auckland Island towards the eradication of its cats, as well as of feral pigs Sus scrofa and House Mice Mus musculus (click here).  The most recent field team had photographed and videoed the cat feeding on the albatross.  Maukahuka Pest Free Auckland Island Project Manager Steve Horn reports that the team tested potential cat baits, with three of the four meat baits tested proving appealing to cats.  The winter team's monitoring also found that mouse numbers on the island had exploded after tussock seeding last summer, which appeared to have also caused an increase in the numbers of young cats.  The field team put GPS collars on 11 cats, adding to the 20 animals already being tracked from last summer.  The tracking has revealed cats range up to 70 square kilometres in search of food and move to steep coastal areas when seabirds, including the White-capped Albatross, have their young.

With “Eradicating Island Pests” as the chosen theme for next year’s inaugural World Albatross Day, ACAP Latest News will continue to post on the fortunes of the Maukahuka - Pest free Auckland Island project.  A report on the feasibility of the project is due to be considered by the Department of Conservation's Island Eradication Advisory Group in the coming weeks.

With thanks to Keith Broome, Finlay Cox and Stephen Horn.

Reference:

Berruti, A. 1981. The status of the Royal Penguin and Fairy Prion at Marion Island, with notes on feral cat predation on nestlings of large birds. Marine Ornithology 9: 123-128.

John Cooper, ACAP Information Officer, 07 October 2019