Cory's Shearwater, photograph by Paulo Catry

Ignacio Munilla (Departamento de Botánica, Universidade de Santiago de Compostela, Spain) and colleagues have published in the on-line and open-access journal PLoS ONE on the likely sources of Cory’s Shearwaters Calonectris borealis settling in new colonies.

The paper’s abstract follows:

“Seabirds are colonial vertebrates that despite their great potential for long-range dispersal and colonization are reluctant to establish in novel locations, often recruiting close to their natal colony.  The foundation of colonies is therefore a rare event in most seabird species and little is known about the colonization process in this group.  The Cory’s shearwater (Calonectris diomedea) is a pelagic seabird that has recently established three new colonies in Galicia (NE Atlantic) thus expanding its distribution range 500 km northwards. This study aimed to describe the establishment and early progress of the new Galician populations and to determine the genetic and morphometric characteristics of the individuals participating in these foundation events.  Using 10 microsatellite loci, we tested the predictions supported by different seabird colonization models.  Possibly three groups of non-breeders, adding up to around 200 birds, started visiting the Galician colonies in the mid 2000’s and some of them eventually laid eggs and reproduced, thus establishing new breeding colonies.  The Galician populations showed a high genetic diversity and a frequency of private alleles similar to or even higher than some of the large historical populations.  Most individuals were assigned to several Atlantic populations and a few (if any) to Mediterranean colonies.  Our study suggests that a large and admixed population is settling in Galicia, in agreement with predictions from island metapopulation models of colonization. Multiple source colonies imply that some birds colonizing Galicia were dispersing from very distant colonies (> 1500 km).  Long-distance colonizations undertaken by relatively large and admixed groups of colonizers can help to explain the low levels of genetic structure over vast areas that are characteristic of most oceanic seabird species.”

Reference:

Munilla, I., Genovart, M., Paiva, V.H. & Velando, A. 2016.  Colony foundation in an oceanic seabird. PLoS ONE 11(2): e0147222. doi:10.1371/journal.pone.0147222.

John Cooper, ACAP Information Officer, 07 March 2016

Hundreds of Black-footed Albatross Phoebastria nigripes chicks were buried up to their necks last month by north-westerly winds that caused a sand storm on the beach the USA’s Kure Atoll, North-western Hawaiian Islands.  Winds were up 40 km/h and with very dry sand resulted in the storm.

Chicks trapped in the sand overheat and die if they are not dug out (as their parents do not dig out their chicks) so Hawaii Department of Land and Natural Resources (DNLR) crew members on the atoll, wearing protective goggles and warm clothes, worked into the late evening to dig out over 400 chicks.  The rescued chicks were doing well some days later.

The Black-footed Albatross depicted here buried up to its neck was incubating an egg on Kure Atoll when it was buried by a severe winter sand storm in 2011.  Climate change may increase the number of storms like these resulting in lower adult survival and reproductive success for seabirds that nest in low lying atolls and islands.  This adult and many others were saved by DLNR staff stationed on the island at the time.

Kure supported 2854 pairs of Black-footed Albatrosses in 2014, as well as 20 073 pairs of Laysan Albatrosses P. immutabilis that tend to breed inland in more vegetated areas.

Photographs by Andrew Sullivan-Haskins and Cynthia Vanderlip, Hawaii Department of Land and Natural Resources.

Follow the Kure Atoll Blog of the Kure Atoll Conservancy.  The conservancy is also on Facebook.

John Cooper, ACAP Information Officer, 04 March 2016

Richard Cuthbert (RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, Sandy, UK) and colleagues are publishing early this year in the Journal of Mammalogy on aspects of the biology of the House Mice Mus musculus of Gough Island, well known for their predatory attacks on albatross and petrel chicks, including of the Critically Endangered Tristan Albatross Diomedea dabbenena.

Rob Ronconi holds a Tristan Albatross chick mortally wounded by Gough's House Mice

The paper’s abstract follows:

“In comparison to the mainland, populations of rodents on islands are often characterized by a suite of life history characteristics termed the “island syndrome.”  Populations of rodents introduced to islands are also well known for their impacts on native species that have evolved in the absence of mammalian predators.  We studied the ecology and behavior of introduced house mice Mus musculus on Gough Island where they are the only terrestrial mammal and where their predatory behavior is having a devastating impact on the island’s burrowing petrel (order Procellariiformes) population and the Critically Endangered Tristan albatross Diomedea dabbenena.  Mice on Gough exhibit extreme features of the island syndrome, including: a body mass 50–60% greater than any other island mouse population, peak densities among the highest recorded for island populations, and low seasonal variation in numbers compared to other studied islands   Seasonal patterns of breeding and survival were linked to body condition and mass, and mice in areas with high chick predation rates were able to maintain higher mass and condition during the winter when mouse mortality rates peak. Within-site patterns of chick predation indicate that proximity to neighboring predated nests and nesting densities are important factors in determining the likelihood of predation.  We conclude that selection for extreme body mass and predatory behavior of mice result from enhanced overwinter survival.  Small mammal populations at temperate and high latitudes are normally limited by high mortality during the winter, but on Gough Island mice avoid that by exploiting the island’s abundant seabird chicks.”

Read more on the depredations of Gough's mice here.

With thanks to Peter Ryan.

Reference:

Cuthbert,R.J., Wanless, R.M., Angel, A., Burle, M.-H., Hilton, G.M., Louw, H., Visser, P., Wilson, J.W. & Ryan, P.G. 2016.  Drivers of predatory behavior and extreme size in house mice Mus musculus on Gough Island.  Journal of Mammalogy DOI:10.1093/jmammal/gyv199.

John Cooper, ACAP Information Officer, 03 March 2016

Junichi Sugishita will be awarded a doctorate by the University of Otago at a graduation ceremony in May this year for his research on foraging by Northern Royal Albatrosses Diomedea sanfordi conducted at Taiaroa Head, New Zealand.

Junichi Sugishita at Taiaroa Head

Junichi (right) fits a tracker to a Northern Royal Albatross, helped by Lyndon Perriman

The abstract of his thesis follows:

 “Monitoring and protection of seabirds that spend much of their lives at sea pose difficult conservation problems.  In the case of pelagic seabirds, such as albatrosses, they can spend up to 95% of their lives at sea, and travel great distances.  During these periods away from breeding colonies, the birds are exposed to a wide range of anthropogenic threats, including interactions with commercial fisheries and exposure to marine pollution.  A detailed knowledge of seabird foraging ecology and behaviour at sea is therefore essential for conservation efforts.

Despite continuous, colony-based management of a small population of endangered northern royal albatross (Diomedea sanfordi) at Taiaroa Head/Pukekura, Dunedin, New Zealand, little is known about the relationship between their at-sea distribution, fisheries overlap, or chick provisioning.   Recent risk assessments of fishery bycatch identified this species to be at-risk from fisheries within the New Zealand Exclusive Economic Zone (EEZ) during breeding. Understanding the nature and spatio-temporal extent of association between fisheries and foraging albatrosses is of important conservation concern.  By incorporating information about at-sea distribution and behaviour with parental provisioning, ongoing albatross management at Taiaroa Head/Pukekura could be facilitated and complemented.

The central aim of this thesis is to gain quantitative insight into the relationship between parental foraging behaviour at sea and provisioning patterns at nests, especially with regard to fine-scale overlap with commercial fisheries, for northern royal albatross breeding at Taiaroa Head/Pukekura.  First, I examined differences between breeders and pre-breeders (i.e. after returning to the colony but prior to the first breeding) in patterns of foraging distribution and activity, and in the relative association with commercial fisheries during the breeding season.  Irrespective of breeding status, birds frequented waters over continental shelf break areas within 250 km of the colony.  Breeders performed longer foraging trips and were more active in prey-searching behaviours at night than were pre-breeders.  An overlap analysis indicated generally low rates of foraging overlap with fisheries, but breeders, compared to pre-breeders, exhibited higher propensity to forage in association with vessels, particularly squid trawlers.  I then investigated the relative importance of intrinsic and extrinsic factors affecting parental provisioning behaviour during the chick-rearing period, as reflected in meal size, foraging trip duration, provisioning rate and colony attendance.  Provisioning rate (g day-1) gradually increased with chick age, largely due to an increase in meal size rather than any increase in feeding frequency.  Results indicate that provisioning behaviour was influenced by the differences in age- and sex-related chick food requirements, other factors related to parental foraging ability, as well as to wind conditions.  Finally, I examined whether foraging in association with a fishing vessel is advantageous for chick provisioning in an attempt to better understand the ecological ramifications of seabird-fishery interactions.  My results suggest that foraging in association with vessels does not confer an advantage for chick feeding, at least for my study birds during the study period.

Overall, the results of this thesis provide new insights into mechanisms shaping patterns of at-sea distribution and chick provisioning of northern royal albatross at Taiaroa Head/Pukekura, emphasising the importance of the localised area along the continental shelf break for this population.  The results obtained here suggest that reproductive constraints play a key role in driving the increased foraging activity in breeders than in pre-breeders, which may lead to the higher tendency for breeders to forage in association with fishing vessels.  By integrating seabird distribution, fishery association, and meal size, this thesis offers a new approach to the growing body of literature on the study of the complex nature of fine-scale overlap between seabirds and fisheries.”

Northern Royal Albatross at sea, photograph by Aleks Terauds

Click here to access a publication on Northern Royal Albatrosses by Dr Sugishita.

With thanks to Junichi Sugishita.

Reference:

Sugishita, J. 2016.  Provisioning and foraging strategies of northern royal albatross (Diomedea sanfordi) at Taiaroa Head/Pukekura, and relationship with fisheries.  PhD Thesis, Dunedin: University of Otago.  158 pp.

John Cooper, ACAP Information Officer, 02 March 2016