Steffen Oppel (Royal Society for the Protection of Birds, Sandy, U.K.) and colleagues have published open-access in the journal Nature Conservation on estimating population size of the Cory’s Shearwater Calonectris borealis.

The paper’s abstract follows:

Population size assessments for nocturnal burrow-nesting seabirds are logistically challenging because these species are active in colonies only during darkness and often nest on remote islands where manual inspections of breeding burrows are not feasible.  Many seabird species are highly vocal, and recent technological innovations now make it possible to record and quantify vocal activity in seabird colonies.  Here we test the hypothesis that remotely recorded vocal activity in Cory’s shearwater (Calonectris borealis) breeding colonies in the North Atlantic increases with nest density, and combined this relationship with cliff habitat mapping to estimate the population size of Cory’s shearwaters on the island of Corvo (Azores).  We deployed acoustic recording devices in 9 Cory’s shearwater colonies of known size to establish a relationship between vocal activity and local nest density (slope = 1.07,R2 = 0.86,p < 0.001).  We used this relationship to predict the nest density in various cliff habitat types and produced a habitat map of breeding cliffs to extrapolate nest density around the island of Corvo.  The mean predicted nest density on Corvo ranged from 6.6 (2.1–16.2) to 27.8 (19.5–36.4) nests/ha.  Extrapolation of habitat-specific nest densities across the cliff area of Corvo resulted in an estimate of 6326 Cory’s shearwater nests (95% confidence interval: 3735–10,524). This population size estimate is similar to previous assessments, but is too imprecise to detect moderate changes in population size over time.  While estimating absolute population size from acoustic recordings may not be sufficiently precise, the strong positive relationship that we found between local nest density and recorded calling rate indicates that passive acoustic monitoring may be useful to document relative changes in seabird populations over time.

Cory's Shearwater, photograph by Paulo Catry

Reference:

Oppel, S., Hervías, S., Oliveira, N., Pipa, T., Silva, C., Geraldes, P., Goh, M., Immler, E. & McKown, M. 2014.  Estimating population size of a nocturnal burrow-nesting seabird using acoustic monitoring and habitat mapping.  Nature Conservation 7: 1-13.

John Cooper, ACAP Information Officer, 07 May 2014

South Africa’s research station at sub-Antarctic Marion Island in the southern Indian Ocean is relieved once a year in April-May.  Returning today on the S.A. Agulhas II are two young researchers who have spent the last 13 months studying albatrosses on the island.

2012 BSc Honours graduates Kim Stevens (University of Cape Town) and Stefan Schoombie (University of KwaZulu-Natal) have been studying Grey-headed Albatrosses Thalassarche chrysostoma and the two sooty albatrosses Phoebetria spp., respectively.

Their two studies have been designed to be comparable.  Utilizing colour-banded birds in long-term monitoring colonies, birds were tracked at sea with back-mounted GPS loggers during three stages in their breeding seasons: early and late incubation and while brooding small chicks.  Deployments were made on 45 Grey-headed, 30 Sooty P. fusca and 15 Light-mantled P. palpebrata Albatrosses.  Return rates with successful downloads were good at 69 out of the 90 devices deployed.  Only a few loggers were lost at sea and some birds had data for more than one foraging trip.

A Grey-headed Albatross flies over a snowy Marion landscape

A Grey-headed Albatross on its nest has been fitted with a back-mounted GPS logger

With albatross crook close by Kim Stevens sits above a study colony on Grey-headed Albatross Ridge

Stefan Schoombie holds a Sooty Albatross on Marion Island

Photographs by Kim Stevens and Stefan Schoombie

In addition, chick regurgitations and squid beak casts were collected on an ad hoc basis to compare with previous studies made on the island, as will be information gathered daily on incubation shifts.

Kim’s study required overnight stays of up to 15 days at a time in a field hut at aptly-named Grey-headed Albatross Ridge on Marion’s south coast – a good day’s walk from the research station on the islands’ eastern side.  Stefan had it a little easier, with some of his study animals being within an hour's walk of the base, although he needed to use fixed ropes as safety aids when working with the sooties that bred on coastal cliffs.

Both Kim and Stefan will now register for Master’s degrees in the Percy FitzPatrick Institute at the University of Cape Town to write up their research findings.  Albatross research at Marion Island is managed by the Institute’s Director, Peter Ryan, who was also on the 2014 relief – as was ACAP’s Information Officer.

Click here for an earlier ACAP news item on research placing "daily diary" loggers on Wandering Albatrosses Diomedea exulans during this year's Marion relief.

John Cooper, ACAP Information Officer, 06 May 2014

The Endangered Black-capped Petrel) Pterodroma hasitata or Diablotin (Little Devil) breeds in remote areas of Haiti and the Dominican Republic, with a population estimated to be 600 to 2000 pairs.

To learn about its at-sea movements in the North Atlantic solar-powered satellite transmitters were placed on three breeding birds last month in the Sierra de Bahoruco along the border between the Dominican Republic and Haiti.  Click here to follow the birds’ journeys.

A Black-capped Petrel is equipped with a solar-powered satellite transmitter

“Much of the habitat loss stems from the desperate situation faced by communities on the Haitian side of the border, which depend on land for farming and fuel wood for cooking.  As a result, the remaining nesting habitat for this species is rapidly becoming deforested and degraded.  This affects the security of nesting colonies in Haiti, but also in the Dominican Republic, since Haitians are often hired by Dominicans to farm and make charcoal for them in the Sierra de Bahoruco, despite its protected area status.  In addition, the species is believed to be threatened by losses from collisions with power lines and communication towers, the periodic outbreak of wildfires and fires associated with forest clearing for farmland, and non-native predators such as rats and cats.” (click here).

The tracking project is being led by Patrick Jodice and Rob Ronconi with institutional backing from the South Carolina Cooperative Fish and Wildlife Research Unit at Clemson University, Grupo Jaragua in the Dominican Republic and American Bird Conservancy through the International Black-capped Petrel Conservation Group.

With thanks to Rob Ronconi for information.

Selected Literature:

Goetz, J.E., Hardesty-Norris, J. & Wheeler, J.A. (Eds) 2012.  Conservation Action Plan for the Black-capped Petrel (Pterodroma hasitata).  International Black-capped Petrel Conservation Group.  26 pp.

Simons, T.R., Lee, D.S. & Haney, J.C. 2013. Diablotin Pterodroma hasitata: a biography of the endangered Black-capped Petrel.  Marine Ornithology 41 (Special Issue): S3-S43.

John Cooper, ACAP Information Officer, 05 May 2014

Leandro Tamini and Leandro Chavez (Albatross Task Force Argentina, Buenos Aires, Argentina) write in the journal Polar Biology on a sighting of an ACAP-listed Buller’s Albatross Thalassarche bulleri in the south-west Atlantic.

The short note’s abstract follows:

“Buller’s Albatross,Thalassarche bulleri, is a New Zealand breeding endemic that is frequently observed in the subtropical and sub-Antarctic South Pacific Ocean between Australia and Peru.  However, in the South Atlantic Ocean, it is a vagrant, as information on its presence in this region is limited to only a few sightings.  Here, we report a new record of T. bulleri in the south-western Atlantic Ocean off Argentina (55°06′13″S, 66°06′44″W) while investigating interactions between commercial fisheries and seabirds.  This record provides new information about the distribution of this albatross species and its relation with fisheries outside of its regular range.”

Buller's Albatross, photograph by Chris Golding

Reference:

Tamini, L.L & Chavez, L.N. 2014.  First record of Buller’s Albatross (Thalassarche bulleri) from a fishing vessel in the south-western Atlantic Ocean off Southern Patagonia (Argentina).  Polar Biology DOI 10.1007/s00300-014-1506-x.

John Cooper, ACAP Information Officer, 04 May 2014