Stephen Totterman (Empire Vale, New South Wales, Australia) writes on-line in the open-access journal Marine Ornithology on differences in measuring Short-tailed Shearwaters Puffinus tenuirostris as study skins or live specimens

The paper’s summary follows:

“External biometrics have many applications in ornithology, and study skins are a major source of these measurements. However, measurements can be imprecise, and skins tend to shrink when they dry — two problems rarely investigated for petrels (family: Procellariidae). This study examined measurement error and shrinkage for 15 biometrics, using Short-tailed Shearwater Puffinus tenuirostris as the subject species. Random measurement error, defined as the variability of repeated measurements of a particular character taken on the same individual relative to its variability among individuals in a particular group, ranged from 0.3% for head plus bill length in dry specimens to 36% for tarsus width in freshly dead birds. Shrinkage of skin specimens stabilised within 2–5 months after preparation. Average fresh-dry shrinkage ranged from 0.2% for head plus bill to 12% for tarsus height. A new method was used to estimate shrinkage variability among individuals. “Shrinkage variation,” defined as the proportion of unexplained variance (1 – r2) in the correlation between paired fresh and dry measurements of a particular character after correcting for measurement error, ranged from 0% for wing chord to 33% for bill base width. More robust biometrics from this study were measurements of large, inflexible characters with well-defined measurement “landmarks.”

Short-tailed Shearwater, photograph by Mark Carey

Reference:

Totterman, S.L. 2016. Random measurement error and specimen shrinkage in Short-tailed Shearwaters Puffinus tenuirostris. Marine Ornithology 44: 11-20.

John Cooper, ACAP Information Officer, 08 March 2016

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