Ryan Carle (Oikonos Ecosystem Knowledge, Santa Cruz, California, U.S.A.) and colleagues have written in the Spanish-language journal La Revista Chilena de Ornitología on the advantages of keeping breeding ACAP-listed Pink-footed Shearwaters Ardenna creatopus and cattle apart with a fence.

The paper’s English abstract follows:

“With the aim of contributing to conservation of breeding habitat of Pink-footed Shearwater (Ardenna creatopus), in 2011 we established a cattle exclusion system around a breeding colony in Isla Robinson Crusoe, Juan Fernández Archipelago, Chile. The cattle exclusion system consisted of a metallic fence 1.6 m in height around a polygon 21 000 m².  After three years, we evaluated the vegetation characteristics inside and outside the cattle-exclusion area by plant sampling in 20 x 20 m plots.  Between 2012-2016, we also monitored 100 burrows in the cattle-exclusion area to assess their structural status.  The exclusion area had a greater overall vegetation cover and increased plant height in comparison to the non-exclusion area.  The non-exclusion area had significantly greater cover of bare soil and of the invasive plant Acaena argentea.  The frequency of occurrence of bare soil and trun [sic] was also significantly greater on the non-exclusion area.  On the exclusion area, we detected a significant increase in cover of annual grasses, forbs and plant litter, and a greater occurrence of lichens compared to the non-exclusion area. We found no evidence of regeneration of native flora within the exclusion area, and the cattle exclusion had no apparent effect on the native fern Blechnum hastatum.  After exclusion, none of the monitored shearwater burrows showed evidence of further damage.  The use of cattle-exclusion fences could be an effective tool for restoration of seabird breeding habitat.”

Pink-footed Shearwater, photograph by Peter Hodum

Reference:

Carle, R.D., Beck, J.N., Colodro, V. & Hodum, P. 2016.  Efectos de la exclusión de ganado vacuno sobre la vegetación en el área ocupada por una colonia de Fardela Blanca (Ardenna creatopus) en la Isla Robinson Crusoe, Chile.  [Effects of cattle exclusion on the vegetation at a Pink-footed Shearwater (Ardenna creatopus) colony on Robinson Crusoe Island, Chile].  La Revista Chilena de Ornitología 22: 184-193.

John Cooper, ACAP Information Officer, 16 December 2016

Dimas Gianuca (Environment and Sustainability Institute, University of Exeter, Penryn, UK) and colleagues have published in the journal Biological Conservation on making a global assessment of seabird bycatch by sex and age.

The paper’s abstract follows:

Fisheries bycatch is a major threat to seabird populations, and understanding sex- and age-biases in bycatch rates is important for assessing population-level impacts.  We analysed 44 studies to provide the first global assessment of seabird bycatch by sex and age, and used generalised models to investigate the effects of region and fishing method. Bycatch was highly biased by sex (65% of 123 samples) and age (92% of 114 samples), with the majority of samples skewed towards males and adults. Bycatch of adults and males was higher in subpolar regions, whereas there was a tendency for more immatures and females to be killed in subtropical waters. Fishing method influenced sex- and age-ratios only in subpolar regions. Sex- and age-biases are therefore common features of seabird bycatch in global fisheries that appear to be associated largely with differences in at-sea distributions. This unbalanced mortality influences the extent to which populations are impacted by fisheries, which is a key consideration for at-risk species. We recommend that researchers track individuals of different sex and age classes to improve knowledge of their distribution, relative overlap with vessels, and hence susceptibility to bycatch. This information should then be incorporated in ecological risk assessments of effects of fisheries on vulnerable species. Additionally, data on sex, age and provenance of bycaught birds should be collected by fisheries observers in order to identify regions and fleets where bycatch is more likely to result in population-level impacts, and to improve targeting of bycatch mitigation and monitoring of compliance.”

Antipodean Albatross: at risk to long-lining, photograph by Colin O'Donnell

Reference:

Gianuca, D.,  Phillips, R.A., Townley, S. & Votier, S.C. 2017  Global patterns of sex- and age-specific variation in seabird bycatch.  Biological Conservation 205: 60–76.

John Cooper, ACAP Information Officer, 15 December 2016

The Flesh-footed Shearwater Ardenna carnepeis has been categorised as Near Threatened in the just-released 2016 list of threatened birds by BirdLife International.

The up-listing follows a review of the bird’s conservation status and call for comments via the BirdLife International Threatened Seabird Forum (click here for the texts).

The uplisting justification follows: “Despite the poor historical records and the current lack of data across all populations to assess the global population, there is now enough evidence to confirm that its population has been strongly affected by the fisheries operating in Australia and the population on Lord Howe and Sandy Island (Australia) and Lady Alice Island (New Zealand) is declining.  Based on such an evidence, it seems reasonable to suspect that the population has declined by at least 20-30% over three generations and thus the species has been uplisted to Near Threatened.”

One forum commentary stated “The species warrants uplisting to Near Threatened, on the basis of the combined set of demographic and population information, most of which is unfavourable, although with high uncertainty associated with most estimates, and the detailed information about threats to the population that are quantified through fisheries observer work.”

The Flesh-footed Shearwater was identified as a potential candidate for listing within the Agreement in a 2008 publication.  It breeds within the territories of Australia, France and New Zealand, all Parties to ACAP.  Two other shearwaters identified as candidate species in 2008, the Critically Endangered Balearic Puffinus mauretanicus and the Vulnerable Pink-footed A. creatopus have subsequently been listed within the Agreement.

Flesh-footed Shearwater, photograph by Barry Baker

Selected Literature:

Baker, G.B. and Wise, B.S. 2005. The impact of pelagic longline fishing on the Flesh-footed Shearwater Puffinus carneipes in Eastern Australia. Biological Conservation 126: 306-316.

Barbraud, C., Booth, A., Taylor, G.A., Waugh, S.M., 2014. Survivorship in Flesh-footed Shearwater Puffinus carneipes at two sites in northern New Zealand.  Marine Ornithology 42: 91-97.

Cooper, J. & Baker, G.B. 2008.  Identifying candidate species for inclusion within the Agreement on the Conservation of Albatrosses and Petrels.  Marine Ornithology 36: 1-8.

Lavers, J.L. 2015.  Population status and threats to Flesh-footed Shearwaters (Puffinus carneipes) in South and Western Australia.  ICES Journal of Marine Science 72: 316-327.

Priddel, D., Carlile, N., Fullagar, P., Hutton, I. and O’Neill, L. 2006. Decline in the distribution and abundance of Flesh-footed Shearwaters (Puffinus carneipes) on Lord Howe Island, Australia. Biological Conservation 128: 412-424.

Waugh, S.M., Tennyson, A.J.D., Taylor, G.A. & Wilson, K.-J. 2013.  Population sizes of shearwaters (Puffinus spp.) breeding in New Zealand, with recommendations for monitoring.  Tuhinga – Records of the Museum of New Zealand Te Papa Tongarewa 24: 159-204.

John Cooper, ACAP Information Officer, 14 December 2016

ACAP Latest News has previously reported that introduced House Mice Mus musculus have taken to attacking and causing the deaths of incubating Laysan Phoebastria immutabilis and Black-footed P. nigripes Albatrosses on Midway Island in the North Pacific (click here).  Planning has now commenced towards their eventual eradication as reported in an article by Meg Duhr-Schultz in the latest issue of Gooney Gazette II, the newsletter of the Friends of Midway Atoll National Wildlife Reserve (FOMA)

An extract from the article follows.

“Last winter, Refuge staff and volunteers discovered that invasive House Mice (Mus musculus) were attacking nesting albatrosses on Sand Island.  Our monitoring revealed that a minimum of 480 nests had bitten birds and at least 70 nests were abandoned following a mouse attack to one of the parents.  Nearly 50 Laysan albatrosses died due to mouse attacks.  Working with veterinarians at the USGS National Wildlife Health Center lab in Honolulu to recover and study many of these carcasses, we found that the birds died of infections that stemmed from the bite wounds.  Mortality of breeding adult albatrosses is a major concern for USFWS and eradicating House Mice has become a high priority.  We recently secured grant funding to support an eradication feasibility study and in October, a team of rodent eradication experts from the non-profit group Island Conservation arrived to Midway Atoll NWR to initiate the study.  The first of several site visits, the group worked with us to understand the social, biological, and abiotic factors that would influence the operations and potential success of a mouse eradication.  The team found that eradicating mice, though it will be costly, challenging, and complex, is indeed feasible.  Currently, the Refuge is taking proactive steps to begin the intensive permitting and regulatory work involved with a rodent eradication, as well as formulating plans for mitigating impacts to non-target species.”

Laysan Albatross pair, photograph by James Lloyd

Reference:

Duhr-Schultz, M. 2016.  From the field.  Updates from the Refuge Biology Program.  Gooney Gazette II Winter 2016/2017.  pp. 8-9.

John Cooper, ACAP Information Officer, 13 December 2016