Paul Sagar (National Institute of Water & Atmospheric Research,  Christchurch, New Zealand) and colleagues have published in the journal Notornis on a decline in a population of the globally Vulnerable Salvin’s Albatross Thalassarche salvini at New Zealand’s Bounty Islands.

The paper’s abstract follows:

"We used data from 3 sources to examine the population size and trend of Salvin’s albatrosses (Thalassarche salvini) breeding on Proclamation Island, Bounty Islands, New Zealand.  Island-wide counts of breeding birds during incubation resulted in totals that declined 14%, from 3065 in 1997 to 2634 in 2004.  A count of breeding albatrosses over part of the island in 2011 indicated a further decline of 13% between 2004 and 2011, and an overall decline of 30% between 1997 and 2011.  Additional counts on part of Depot Island indicated a decline of 10% in the numbers of breeding pairs between 2004 and 2011.  Daily observations of 70 nests showed that hatching spanned the period from 5 to 21 November 1997, with a median of 15 November, apart from 5 eggs that had not yet hatched by the end of the study period.  Based on the banding and recapture of chicks banded in March 1985 annual survival was estimated at 0.926.  The scale of the decline estimated in this population has resulted in the conservation status of Salvin’s albatross being upgraded from nationally vulnerable to nationally critical."

Salvin's Albatross, photograph by Paul Sagar

Reference:

Sagar, P.M., Amey, J., Scofield, R.P. & Robertson, C.J.R. 2015.  Population trends, timing of breeding and survival of Salvin's albatrosses (Thalassarche salvini) at Proclamation Island, Bounty Islands, New Zealand. Notornis 62:21-29.

John Cooper, ACAP Information Officer, 23 April 2015

The locality in the Falkland Islands (Islas Malvinas)* with the greatest number of breeding ACAP-listed Southern Giant Petrels Macronectes giganteus is Sandy Cay in the Elephant Cays group off the south-west coast of East Falkland.  A total of 10 936 breeding pairs was counted on aerial photographs taken on 08 December 2004 and 7474 chicks on photos taken on 14 January 2005, giving an estimated breeding success of 68%.  The entire colony, the World’s largest for the species, was in one area and was relatively compact.  Breeding of about 1000 pairs of Southern Giant Petrels in the Elephant Cays was recorded in 1986/87, with “hundreds” prior to the 1960s.

Aerial view of the Southern Giant Petrel colony on Sandy Cay, photograph from Reid & Huin [2005] 

Views of Sandy Cay showing tussock and beaches, photographs by  Ken Passmore

Sandy Cay is an 84-ha island with a 4-km coastline largely surrounded by kelp beds.  It is low-lying, flat-topped and roughly oval-shaped, made up of dense and ungrazed Tussac Grass Parodiochloa flabellata, grass meadows and boulder and sandy beaches and dunes, with three fresh-water bodies.  The single giant petrel colony is situated in the north of a 700-m long sandy beach in the north-east of the cay.

The Southern Giant Petrel breeing colony on Sandy Cay, photographs by Ken Passmore

The island is privately owned and operated as a wildlife sanctuary or nature reserve with landings very rarely allowed.  It forms part of BirdLife International’s Important Bird Area for the Elephant Cays (FK05).  Sandy Cay has been stocked with cattle in the past, but now appears to have no introduced mammals, including rodents, based on a ground visit on 28 April 2010.  The collection of giant petrel eggs for human consumption by visiting vessels in the first half of the 20th Century has been reported, suggesting the colony is one of long standing.

With thanks to Ken Passmore, Sally Poncet, Tim Reid and Anton Wolfaardt for information and photographs.

Selected Literature:

[Falklands Conservation] 2006.  Important Bird Areas of the Falkland Islands.  London: Falklands Conservation.  160 pp.

Passmore, K. & Poncet, S. 2010.  Assessment of the Presence of Rodents and Baseline Surveys on Elephant Cays, Stinker Island, Penn Island, Third Island and Fourth Island.  [Stanley]: Beaver Island LandCare.  54 pp.

Patterson, D.L., Woehler, E.J., Croxall, J.P., Cooper, J., Poncet, S., Peter, H.-U., Hunter, S. & Fraser, M.W. 2008.  Breeding distribution and population status of the Northern Giant Petrel Macronectes halli and Southern Giant Petrel M. giganteus.  Marine Ornithology 36: 115-124 and appendix.

Reid, T. & Huin, N. [2005].  Census of the Southern Giant-Petrel Population of the Falkland Islands 2004/2005.  [Stanley]: Falklands Conservation.  26 pp.

Reid, T. & Huin, N. 2008.  Census of the Southern Giant Petrel population of the Falkland Islands 2004/2005.  Bird Conservation International 18: 118-128.

Wolfaardt, A.[C.], Rendell, N. & Brickle, P. 2010.  Falkland Islands Implementation Plan for the Agreement on the Conservation of Albatrosses and Petrels (ACAP): Review of Current Work and a Prioritised Work Programme for the Future.  Stanley: Falkland Islands Government.  57 pp.

Woods, R.W & Woods, A, 1997.  Atlas of the Breeding Birds of the Falkland Islands. Oswestry; Anthony Nelson.  190 pp.

Woods, R., Ingham, R. & Brown, A. 2006.  Falkland Islands.  In: Sanders, S. (Ed.).  Important Bird Areas in the United Kingdom Overseas Territories.  Sandy: Royal Society for the Protection of Birds.  pp. 99-162.

John Cooper, ACAP Information Officer 22 April 2015

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur y Islas Sandwich del Sur) and the surrounding maritime areas.

Michael Tabak (Program in Ecology, Department of Zoology & Physiology, University of Wyoming, Laramie,USA) and colleagues have looked at the distribution of Brown or Norway Rats Rattus norvegicus in the Falkland Islands (Islas Malvinas)*, publishing open access in the online journal NeoBiota.  The finding that rats are likely to be able to swim farther than previously thought has implications for judging the suitability of islands cleared of rats for the reintroduction or translocation of burrowing shearwaters and petrels.

The paper’s abstract follows:

“Non-native rats (Rattus spp.) threaten native island species worldwide.  Efforts to eradicate them from islands have increased in frequency and become more ambitious in recent years. However, the long-term success of some eradication efforts has been compromised by the ability of rats, particularly Norway rats (Rattus norvegicus) which are good swimmers, to recolonize islands following eradications.  In the Falkland Islands, an archipelago in the South Atlantic Ocean, the distance of 250 m between islands (once suggested as the minimum separation distance for an effective barrier to recolonization) has shown to be in­sufficient.  Norway rats are present on about half of the 503 islands in the Falklands.  Bird diversity is lower on islands with rats and two vulnerable passerine species, Troglodytes cobbi (the only endemic Falkland Islands passerine) and Cinclodes antarcticus, have greatly reduced abundances and/or are absent on islands with rats.  We used logistic regression models to investigate the potential factors that may determine the presence of Norway rats on 158 islands in the Falkland Islands.  Our models included island area, distance to the nearest rat-infested island, island location, and the history of island use by humans as driving vari­ables.  Models best supported by data included only distance to the nearest potential source of rats and island area, but the relative magnitude of the effect of distance and area on the presence of rats varied depending on whether islands were in the eastern or western sector of the archipelago.  The human use of an island was not a significant parameter in any models.  A very large fraction (72%) of islands within 500 m of the nearest potential rat source had rats, but 97% of islands farther than 1,000 m away from potential rat sources were free of rats.”

Pycroft's Petrel: being translocated in New Zealand

Click here for a related paper on rodents in the Falkland Islands (Islas Malvinas)*.

References:

Tabak, M.A., Poncet S., Passfield, K, Carling M.D. & Martinez del Rio C 2014.  The relationship between distance and genetic similarity among invasive rat populations in the Falkland Islands.  Conservation Genetics 16: 125-135.

Tabak, M.A., Poncet, S., Passfield, K. & Martinez del Rio, C. 2015.  Modeling the distribution of Norway rats (Rattus norvegicus) on offshore islands in the Falkland Islands.  NeoBiota 24: 33-48.

John Cooper, ACAP Information Officer, 21 April 2015

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur y Islas Sandwich del Sur) and the surrounding maritime areas.

Shannon Lyday (Hawaii Pacific University, Oceanic Institute, Waimanalo, Hawaii, USA.) and colleagues write in a special issue of the Journal of Marine Systems entitled “California Current System – Predators and the Preyscape” on shearwaters (including the ACAP-candidate Pink-footed Puffinus creatopus) as indicators of fish abundance.

The paper’s abstract follows:

“Shearwaters are ideal for monitoring ocean conditions in the California Current because these predators are abundant, conspicuous, and responsive to oceanographic variability.  Herein we evaluated black-vented (Puffinus opisthomelas), Buller's (P. bulleri), flesh-footed (P. carneipes), pink-footed (P. creatopus), short-tailed (P. tenuirostris), and sooty (P. griseus) shearwaters as fishery-independent indicators of predatory or prey fish availability.  We analyzed four years (1996, 2001, 2005, 2008) of monthly (August–November) National Oceanic and Atmospheric Administration seabird surveys, and United States Geological Survey Pacific Coast Fisheries Database catch, from the California coast to 200 nm offshore.  An ordination of shearwater abundance and fish catch revealed that the shearwaters and 11 fish/squid species were significantly correlated with one or more of three principal components, which explained 86% of the variation and revealed distinct species assemblages.  We evaluated multiple linear regression models for 19 fisheries using five shearwater metrics: density, aggregation, and behavior (traveling, stationary, feeding), three oceanographic indices, and latitude.  Eight of these models had a shearwater metric as the primary predictor.  In particular, feeding black-vented shearwater abundance explained 75% of dolphinfish (Coryphaena hippurus) longline catch.  This research illustrates the utility of shearwaters as ecosystem indicators, with direct application for predicting fishery catch of commercial importance.”

Sooty Shearwater, photograph by John Graham 

Reference:

Lyday, S.E., Ballance, L.T., Field, D.B. & Hyrenbach, K.D. 2015.  Shearwaters as ecosystem indicators: towards fishery-independent metrics of fish abundance in the California Current.  Journal of Marine Systems 146: 109-120.

John Cooper, ACAP Information Officer, 20 April 2015