Victoria Bakker (Department of Ecology, Montana State University, Bozeman, USA) and colleagues have published open access in the journal Biological Conservation on the problem of using nests counts for population estimates when not all Black-footed Phoebastria nigripes and Laysan P. immutabilis Albatrosses breed annually.

The paper’s abstract follows:

“Pelagic predators such as albatross have long been of conservation concern, but assessing their status poses numerous challenges. A standard monitoring method for albatross is colony-based nest counts to track numbers of breeders. However, a variable proportion of the population skips breeding in any given year and cannot be quantified by nest counts, creating several complications to efforts in understanding population dynamics. We used stochastic demographic matrix models for black-footed (Phoebastria nigripes) and Laysan (P. immutabilis) albatross to investigate: i) the potential for the skipping behavior of breeders to create apparent density dependence in nest counts, ii) the limitations to assessing population trends from nest counts and implications for evaluating impacts from fisheries bycatch, including calculating Potential Biological Removal values, and iii) the relative importance of at-sea versus on-island threats to population viability. We found the increased likelihood of these albatrosses skipping breeding following a successful season – a feature common to many seabirds and other taxa – results in substantial negative temporal auto-correlation in the observable population that can be misinterpreted as negative density dependence, with important implications for inferences about population viability. Black-footed albatross appear limited by fisheries bycatch, while Laysan albatross, which have low estimated bycatch mortality, are currently at greater risk from island-based threats. Our results suggest a cautionary approach to managing black-footed and Laysan albatross should be adopted because detecting population declines from nest counts could take decades. Ultimately, we highlight the inherent difficulties in assessing population status and trends in long-lived species such as albatross.”

Black-footed and Laysan Albatrosses, photograph from the Kure Atoll Conservancy

Reference:

Bakker, V., Finkelstein, M.E., Doak, D.F., VanderWerf, E.A., Young, L.C., Arata, J.A., Sievert, P.R. & Vanderlip, C. 2018. The albatross of assessing and managing risk for long-lived pelagic seabirds. Biological Conservation 217: 83-95.

John Cooper, ACAP Information Officer, 09 January 2018

The globally Near Threatened Black-footed Albatross Phoebastria nigripes is a non-breeding visitor to Canada’s Pacific waters, where it is at risk to mortalities caused by longline fishing. The albatross was listed as a species of Special Concern ("species at risk of becoming threatened or endangered"; roughly equivalent to a status of Near Threatened) by Canada in 2007 (click here). 

A final management plan has now been produced for the Black-footed Albatross in Canadian waters.

The plan’s executive summary follows:

“The Black-footed Albatross is a long-lived seabird that breeds mainly in the Northwestern Hawaiian Islands and occurs at sea off the Pacific Coast of Canada during the breeding and non-breeding seasons. Significant numbers feed off the coast of British Columbia each year, including adults making long foraging trips to feed their young.

The population seems generally stable, but relatively high numbers are caught as bycatch in longline fisheries in the North Pacific. Additionally, adults and immature birds are affected by the accumulation of toxic chemicals and heavy metals and by the ingestion of waste plastics from the surface of the sea when they are feeding. Because of the unknown effect of these particular threats over the long term, the Black-footed Albatross has been listed as a species of Special Concern in Canada. Emerging threats such as the potential loss of nesting and foraging habitat due to climate change also threaten this species.

The management objective for the Black-footed Albatross is to “...help to increase global population numbers and maintain the population throughout its documented distribution in Canadian waters, by reducing at-sea mortality and otherwise augmenting international conservation efforts.” The conservation of the Black-footed Albatross cannot succeed by Canadian efforts alone due to the wide-ranging marine nature and distant nesting habitats of this species.

Actions already underway include long-term at-sea surveys that record Black-footed Albatross distribution and abundance in Canada, and assessments of longline bycatch mortality in Canadian Pacific waters, including monitoring of current bycatch levels. Bycatch mitigation measures have been implemented in the target fishing fleet, but monitoring for compliance and effectiveness is limited and should be increased. Strategies and measures to achieve the management objectives are presented in the section entitled Broad Strategies and Conservation Measures.”

Click here for an earlier report on the management plan in ACAP Latest News.

A colour-banded Black-footed Albatross at sea, photograph by Vicki Miller

With thanks to Ken Morgan.

Reference:

Environment and Climate Change Canada. 2017. Management Plan for the Black-footed Albatross (Phoebastria nigripes) in Canada. Species at Risk Act Management Plan Series. Ottawa: Environment and Climate Change Canada. iv + 30 pp.

Click here for the French text.

John Cooper, ACAP Information Officer, 08 January 2018

The globally Endangered Hutton’s Shearwater Puffinus huttoni breeds at altitude in the Seaward Kaikoura Range on New Zealand’s South Island. In November 2016 the area was severely impacted by an earthquake which caused landslides within the two known colonies during the breeding season, leading to fears that many of the breeding birds would have been killed in their burrows (see earlier articles in ACAP Latest News).

Hutton's Shearwater outside its burrow

Last month the Hutton’s Shearwater Charitable Trust used earthquake assessment funding to send Richard Cuthbert, who had previously studied the bird for his PhD, and three Department of Conservation rangers to see what damage the earthquake had caused to the shearwater’s breeding sites (click here).

The Kowhai Valley colony at the site of a large landslide/rockfall that destroyed c. 12% of the breeding area

 View from a helicopter of the Shearwater Stream colony showing landslides caused by the November 2016 earthquake

Photographs by Richard Cuthbert

 “About 20-30% of the breeding burrows [in the Kowhai Stream colony] have been destroyed, which is better than biologists feared, and there is lots of bird activity in the colony which bodes well for its recovery.”

Despite the changes from the earthquake the larger Kowhai Stream colony was still deemed inaccessible to feral pigs, which are believed to have caused the extinction of other colonies in the mountain range.

The smaller Shearwater Stream colony was only viewed from the air because it was not considered safe to land; although burrow numbers were estimated to have dropped by a similar 20-30%.  Listen to a radio interview with Richard after his survey here.

Click here to read ACAP’s review of Richard Cuthbert’s book Seabirds beyond the Mountain Crest, written about his research conducted on Hutton’s Shearwater.

With thanks to Richard Cuthbert for information and photographs.

John Cooper, ACAP Information Officer, 05 January 2018

Over the last few decades efforts, mostly successful, have been made to eradicate introduced predatory mammals on many of the Southern Ocean’s sub-Antarctic islands, notably New Zealand’s Campbell Island and Australia’s Macquarie Island among others. For some islands (e.g. New Zealand’s Antipodes) final results of eradication attempts are still awaited. Plans are being made to rid the UK’s Gough Island and South Africa’s Marion Island of their introduced House Mice Mus musculus over the next three years. An ambitious plan to rid New Zealand’s Auckland Island of its feral pigs Sus scrofus domesticus and cats Felis catus, as well as of its mice, is also currently being developed.

News is now to hand that the French have commenced a year’s research on the feral cats, Norway Rats Rattus norvegicus and House Mice on Amsterdam Island in the southern Indian Ocean (click here). Population estimates of rodents will be made, and cats will be monitored with camera traps.

Amsterdam Island, photograph from Thierry Micol

According to the article, the Norway Rat is suspected of being a carrier for the bacterium Pasteurella multocida, responsible for avian cholera which kills chicks of the globally Endangered Indian Yellow-nosed Albatross Thalassarche carteri, on the island, of which two- thirds of the world population breeds on Amsterdam’s Entrecasteaux cliffs. Rats will be sampled for Pasteurella.

Indian Yellow-nosed Albatross with its chick, photograph by Jeremy Demay

The intention is for the research to inform planning for the simultaneous eradication of the three alien mammals. The island’s feral cattle Bos taurus were eradicated in 2010 (click here).

ACAP Latest News will report on progress towards a pest-free Amsterdam Island as information becomes available, in the expectation that in time it will join the growing panoply of pest-free islands in the Southern Ocean.

Read more here.

References:

TAAF 2010. Plan de gestion 2011 - 2015 Réserve naturelle des Terres australes françaises. Saint Pierre, La Réunion: Terres australes et antarctiques françaises. 35 pp.

Weimerskirch, H. 2004. Diseases threaten Southern Ocean albatrosses. Polar Biology 27: 374-379.

John Cooper, ACAP Information Officer, 04 January 2018