Richard Phillips (British Antarctic Survey, Cambridge, UK) and colleagues have published in the ornithological journal Ibis on breeding-site vagrancy and hybridization in albatrosses.

The short communication’s abstract follows:

“Given the rarity of hybridization in seabirds, which presumably relates to their very high philopatry, the degree of breeding‐site vagrancy should correspond with the incidence of mixed‐species pairing, although not necessarily with the production of hybrids if there are behavioural or genetic barriers to successful reproduction. Using molecular methods, we verified that two of the three chicks hatched by a vagrant male White‐capped Albatross Thalassarche steadi paired with a female Black‐browed Albatross Thalassarche melanophris at South Georgia were genuine hybrids (these chicks died before fledging, but a third chick – the result of an extra‐pair copulation – fledged successfully). In a wider review, we could find only five known or suspected mixed‐species pairs, and three different hybrids in albatrosses, mostly between closely related species. This appears to reflect behavioural barriers to hybridization in sympatric species and the low incidence of breeding‐site vagrancy (which mainly involves single individuals that invariably associate with the most phenotypically similar local taxon). Breeding‐site vagrancy is most frequent in the ‘shy‐albatross’ complex, which could explain why genetic divergence occurred more recently in this group than in other Thalassarche, and hence exploratory behaviour appears to be more important than numerical abundance or breeding distribution in driving colonization as well as hybridization processes in albatrosses.”

Vagrant White-capped Albatross on Bird Island, photograph by Richard Phillips

Read more about vagrancy in albatrosses here.

Reference:

Phillips, R.A., Cooper, J. & Burg, T.M. 2018.  Breeding‐site vagrancy and hybridization in albatross.  Ibis https://doi.org/10.1111/ibi.12622.

John Cooper, ACAP Information Officer, 11 October 2018

Stefan Oppel (Centre for Conservation Science, Royal Society for the Protection of Birds, United Kingdom) and colleagues have published in the journal Marine Policy on an analysis of tracking data for 52 Atlantic seabird species, including 10 ACAP-listed albatrosses and petrels.

The paper’s abstract follows:

“Knowing the spatial scales at which effective management can be implemented is fundamental for conservation planning. This is especially important for mobile species, which can be exposed to threats across large areas, but the space use requirements of different species can vary to an extent that might render some management approaches inefficient. Here the space use patterns of seabirds were examined to provide guidance on whether conservation management approaches should be tailored for taxonomic groups with different movement characteristics. Seabird tracking data were synthesised from 5419 adult breeding individuals of 52 species in ten families that were collected in the Atlantic Ocean basin between 1998 and 2017. Two key aspects of spatial distribution were quantified, namely how far seabirds ranged from their colony, and to what extent individuals from the same colony used the same areas at sea. There was evidence for substantial differences in patterns of space-use among the ten studied seabird families, indicating that several alternative conservation management approaches are needed. Several species exhibited large foraging ranges and little aggregation at sea, indicating that area-based conservation solutions would have to be extremely large to adequately protect such species. The results highlight that short-ranging and aggregating species such as cormorants, auks, some penguins, and gulls would benefit from conservation approaches at relatively small spatial scales during their breeding season. However, improved regulation of fisheries, bycatch, pollution and other threats over large spatial scales will be needed for wide-ranging and dispersed species such as albatrosses, petrels, storm petrels and frigatebirds.”

Grey-headed Albatross at sea: one of the 10 ACAP-listed species in the study; photograph by Kirk Zufelt

Reference:

Oppel, S. et al. 2018.  Spatial scales of marine conservation management for breeding seabirds.  Marine Policy 98: 37-46.

John Cooper, ACAP Information Officer, 10 October 2018

Critically Endangered Tristan Albatrosses Diomedea dabbenena breeding on World Heritage Gough Island in the South Atlantic are at great risk of extinction due in part to introduced House Mice Mus musculus attacking and killing their chicks in the hours of darkness during winter months – as has been regularly reported in ACAP Latest News (watch a video on mouse attacks).

Incubating female Tristan Albatross on Gough Island, photograph by John Cooper

Mice attack a Tristan Albatross downy chick at night; it died soon afterwards.  Photograph by Ross Wanless

In September this year the island-wide annual count of all albatross chicks which had survived the austral winter was once more undertaken by a Gough Island Restoration Programme team from the UK’s Royal Society for the Protection of Birds (RSPB).  The count followed a count of incubating birds made in January, allowing an estimate of overall breeding success to be made.

Of 1453 nests with eggs counted at the beginning of the year only 309 chicks were found to have survived until late September.  Breeding success so far is thus estimated at only 21%.  However, since carcasses of large chicks are still being found on the island breeding success will probably drop even lower.  Modelling research has shown that the consistently low breeding success figures of the last decade are insufficient to allow the near-endemic population to remain stable, leading to the bird's Critically Endangered status.

It is intended to attempt to eradicate the mice by poison-bait drop in 2020 (click here).  If successful, the Tristan Albatross will at last have a chance of a “normal” breeding season, with an expected 70-75% breeding success.  Here’s hoping!

The Gough Island Restoration Programme is run by the RSPB in partnership with the Tristan da Cunha Government, BirdLife South Africa, the South African Department of Environmental Affairs and Island Conservation.

Information from Michelle Risi Jones, the Gough Island Restoration Programme and an RSPB blog.

John Cooper, ACAP Information Officer, 09 October 2018

The 2018 intersessional meeting of the Indian Ocean Tuna Commission (IOTC) Working Party on Ecosystems and Bycatch (WPEB-14) was held in Cape Town, South Africa, from 10-14 September 2018.

The Albatross and Petrel Agreement was represented by Anton Wolfaardt, Co-convenor of its Seabird Bycatch Working Group. The meeting considered a number of seabird-related papers, one of which (IOTC-2018-WPEB14-26) was submitted and presented by ACAP, outlining its latest best-practice advice for mitigating seabird bycatch in pelagic longline fisheries. The WPEB re-iterated its support for the ACAP best-practice advice, which has also previously been endorsed by the IOTC’s Scientific Committee.

There was a range of other seabird-related papers and issues discussed at the meeting, all available online. These included a report of recent estimates of seabird bycatch associated with the Spanish surface longline fleet targeting swordfish in the Indian Ocean (IOTC-2018-WPEB14-23), different methodological approaches to assessing seabird bycatch (IOTC-2018-WPEB14-24; IOTC-2018-WPEB14-25; and IOTC-2018-WPEB14-45), and the results of a pilot project to investigate the value of using trans-shipment observers as a tool for understanding the use of seabird bycatch mitigation measures on vessels operating on the high seas (IOTC-2018-WPEB14-44).  Click here to access these and the other meeting documents and information papers considered by the working party.

The abstract of ACAP’s meeting document follows:

“The incidental mortality of seabirds, mostly albatrosses and petrels, in longline fisheries continues to be a serious global concern and was the major reason for the establishment of the Agreement on the Conservation of Albatrosses and Petrels (ACAP). ACAP routinely reviews the scientific literature regarding seabird bycatch mitigation in fisheries, and on the basis of these reviews updates its best practice advice. The most recent review was conducted in September 2017, and this document presents the outcome of that review and the summary advice pertaining to best practice measures for mitigating seabird bycatch. ACAP has confirmed that a combination of weighted branch lines, bird scaring lines and night setting remains the best practice approach to mitigate seabird bycatch in pelagic longline fisheries. In addition, ACAP has since 2016 also endorsed the inclusion in the list of best practice mitigation measures of two hook-shielding devices. These devices encase the point and barb of baited hooks until a prescribed depth or immersion time has been reached (set to correspond to a depth beyond the diving range of most seabirds) thus preventing seabirds gaining access to the hook and becoming hooked during line setting. On the basis of the September 2017 review, the only update to the ACAP best practice advice for reducing bycatch of seabirds in pelagic longline fisheries related to recommendations concerning the aerial extent, streamer line configuration, attachment height and weak link of bird scaring lines for small (<35m) vessels.”

Click here to access ACAP’s 26-page meeting document.

Photograph from BirdLife South Africa

Anton Wolfaardt, Co-convenor, ACAP Seabird Bycatch Working Group, 08 October 2018