Uwe Horst Schulz (Laboratório de Ecologia de Peixes, Universidade do Vale do Rio dos Sinos, São Leopoldo, Rio Grande do Sul, Brazil) and colleagues have published in the Japanese journal Zoological Science on gender differences during breeding by Southern Giant Petrels Macronectes giganteus.

The paper’s abstract follows:

“Differences in nest attendance between genders in seabirds may be related to morphological differences.  Southern giant petrel is a dimorphic species with gender-specific foraging behavior.  The objective of this study was to investigate sex-related differences in nest attendance during the breeding period of southern giant petrels by presence/absence patterns of both sexes during incubation and compare use of the colony after nest failure.  Fourteen birds were tagged with digitally coded radio-transmitters in a colony at Elephant Island, Antarctica, in the beginning of 2009/2010 breeding season.  Females were present during 18 periods (min. 3 days, max. 9 days) and males only in five periods (min. 2 days, max. 13 days).  The difference in mean number of radio signals per day between females (4330; s.e. 313.5) and males (2691; s.e. 248.6) was highly significant (t = 4.3; d.f. = 199; P < 0.001; Fig. 4).  As consequence of the severe weather conditions that year, all tagged birds failed to reproduce.  After abandonment of the nests, the presence of both genders decreased drastically, although the tagged individuals stayed in the area.  Under severe weather conditions female Southern Giant Petrels continue breeding while males abandon the nest earlier.”

A Southern Giant Petrel in Antarctica, photograph by Michael Dunn

Reference:

Schulz, U.H., Krüger, L. & Petry, M.V. 2014.  Southern Giant Petrel Macronectes giganteus nest attendance patterns under extreme weather conditions.  Zoological Science: 501-506.

John Cooper, ACAP Information Officer, 12 August 2014

Alice Jones (The Environment Institute & School of Ocean and Earth Sciences, University of Adelaide, Australia) and colleagues have published open access in the journal Endangered Species Research on the at-sea distribution of the ACAP-listed and Critically Endangered Balearic Shearwater Puffinus mauretanicus.

The paper’s abstract follows:

“We investigated spatio-temporal distribution patterns of the Critically Endangered Balearic shearwater Puffinus mauretanicus in the northern part of its migratory range, using a combination of effort-corrected land- and boat-based survey data (2007-2010).  The species was recorded regularly along the western English Channel (Western Channel) coasts of northwest France and the southwest UK, with peak counts occurring during the summer and autumn months.  Foraging aggregations comprising hundreds to thousands of birds (~1 to 20% of the global population) were recorded in the large shallow embayments of northern Brittany in all survey years.  Elsewhere, most birds were recorded on passage, with maximum birds-per-hour (BPH) of 169 off northwest France and 36 off the southwest UK.  Few birds were recorded offshore, beyond sight of land.  A distance-from-shore analysis revealed that the species passed closer to shore than other pelagic seabirds such as sooty shearwater Puffinus griseus.  A constant-effort seasonal survey from the southwest tip of the UK mainland recorded the species on 93% of survey days, with BPH rates peaking in the morning between 08:00 and 11:00 h.  These results have important monitoring and conservation implications for this Critically Endangered species.  In particular, the records of large aggregations in spatially restricted areas of the Western Channel during the inter-breeding period suggests the species could be vulnerable to impacts such as oil spills, or disturbance from offshore construction projects.  We also provide evidence that some birds remain in the survey area during the breeding season, suggesting it may be an important site for non-breeding birds.”

Balearic Shearwater, photograph by Henri Weimerskirch

Reference:

Jones, A.R., Wynn, R.B., Yésou, P., Thébault, L., Collins, P., Suberg, L., Lewis, K.M. & Brereton,T.M. 2014.  Using integrated land- and boat-based surveys to inform conservation of the Critically Endangered Balearic shearwater.  Endangered Species Research 25:1-18.

For the paper’s supplementary material click here.

John Cooper, ACAP Information Officer, 11 August 2014

Karen Bourgeois (School of Biological Sciences, Auckland University, New Zealand) and colleagues have published in the journal Acta Ornithologica on site and mate selection in the Vulnerable Yelkouan Shearwater Puffinus yelkouan, a candidate species for ACAP listing.

The paper’s abstract follows:

“Nest and mate choice is important in seabirds, influencing reproductive performance as both nest-site and partner quality varies.  The Yelkouan Shearwater Puffinus yelkouan nests mainly in pre-existing cavities and to a lesser extent in cavities it excavates.  We have monitored breeding colonies of the Yelkouan Shearwater on two islands of the Hyères archipelago, south-east of France, for nine years to analyse nest-cavity and mate selection, to evaluate nest-cavity and mate fidelity, and to investigate their relationships with reproductive performance.  Yelkouan Shearwaters selected nest-cavities providing a high degree of concealment and protection.  Reproductive performance and fidelity to cavity were highest in deep cavities with a winding tunnel and a steep slope around the entrance. Mating was assortative for bill and tarsus measurements.  High rates of return to the same cavity (94.7%) and mate (95.5%) were recorded.  Fidelity to nest-cavity was highest when breeding succeeded the previous year (fidelity rate: 97.3% in successful breeders vs. 87.8% in unsuccessful breeders) and was most likely to result in successful breeding the same year (breeding success: 67.5% in faithful breeders vs. 43.8% in movers).  The rate of divorce was low (4.5%), did not differ between islands and was not associated with breeding performance.  However, breeding success increased by 22.2 ± 9.9% after mate change following a divorce or the absence of a previous mate.  Such high rates of nest-cavity and mate fidelity could indicate a good population status with breeding habitat, food resource and mates of good quality.”

Yelkouan Shearwater, photograph by Jerome Lagrand

With thanks to Karen Bourgeois for information.

Reference:

Bourgeois, K., Dromzée, S. & Vidal, E. 2014.  Relationships between nest-cavity and mate selection, reproductive performance and fidelity in the Mediterranean endemic Yelkouan Shearwater Puffinus yelkouan.  Acta Ornithologica 49: 9-22.

John Cooper, ACAP Information Officer, 10 August 2014

The licensed longline fishery for Patagonian Toothfish Dissostichus eleginoides in the French Exclusive Economic Zone (EEZ) around the sub-Antarctic Kerguelen Islands has reported to the Working Group on Fish Stock Assessment (WG-FSA) of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) that 18 seabird mortalities were observed in the 2012/13 fishing season, consisting of 16 White-chinned Petrels Procellaria aequinoctialis and two Northern Giant Petrels Macronectes halli.  An estimated extrapolated mortality of 70 birds was calculated.

From 2007 to 2013 a total of 690 birds of three species (all ACAP-listed and including the Grey Petrel P. cinerea) were reported killed over the seven-year period, with a decline from a high of 257 in 2008.  White-chinned Petrels were the most commonly killed, at 608 over seven years.

Grey Petrel at sea, photograph by Peter Ryan

Conservation Measure 25-02 ‘Minimisation of the incidental mortality of seabirds in the course of longline fishing or longline fishing research in the CAMLR Convention Area’ was adhered to in the fishery.  An exemption was allowed to the requirement for night setting by achieving the sink rates described in CM 25-02 and subject to a seabird by-catch limit.

The report states that “[a]dditional measures for the upcoming season will also be applied … , including:

(i) changes to the bird exclusion device to ensure it is effective in all weather conditions

(ii) closure of fishing areas and quota allocation reduction to vessels that have high by-catch rates

(iii) education and training will be strengthened by regular meetings between TAAF and fishing masters of vessels with high by-catch

(iv) data will continue to be collected and submitted using CCAMLR standard methods and forms

(v) a demographic study on the white-chinned petrel will be undertaken at Kerguelen Island, as well as the continued population counts of white-chinned petrels on the Kerguelen archipelago.”

Reference:

CCAMLR  2013.  Fishery Report 2013: Dissostichus eleginoides Kerguelen Islands French EEZ (Division 58.5.1).  Hobart: Commission for the Conservation of Antarctic Marine Living Resources.  9 pp.

John Cooper, ACAP Information Officer, 09 August 2014