Twenty-two Laysan Albatross Phoebastria immutabilis chicks have disappeared over the past three weeks from a wildlife refuge on the USA’s island of Kauai, with feral Domestic Cats Felis catus being suspected as the culprits (click here and here).

A Laysan Albatross incubates its egg on Kauai, photograph by Hob Osterlund

As a consequence traps have been set and so far eight cats have been caught.  “We’ve noticed the mortality has subsided since we’ve removed eight cats,” said Michael Mitchell of the Kauai National Wildlife Refuge Complex.  The complex includes the Kīlauea Point National Wildlife Refuge where 115 to 130 pairs of Laysan Albatrosses breed unprotected by a predator-proof fence that would keep out cats, as has proved successful at the Kaena Point Natural Area Reserve on the nearby island of Oahu (click here and here).

A live-trapped cat

As well as the suspected cats killing chicks, domestic dogs Canis familiaris running loose have from time to time killed numbers of adult Laysan Albatrosses on Kauai (click here).

Unlike some of the other main Hawaiian islands Kauai apparently does not have an established population of alien Small Indian Mongoose Herpestes javanicus, a known seabird predator, although two animals were live-trapped on the island in 2012 (click here).

To view photos and accounts of Laysan Albatrosses breeding on Kauai visit My Albatross Diary, the Kaua’i Albatross Network and The Albatross of Kaua’i.  There's also a live-streaming webcam, in its second year, that is keeping watch on two Laysan nests, currently with small chicks (click here and here).  

John Cooper, ACAP Information Officer, 21 February 2015

Sarah Gall and Richard Thompson (Marine Biology & Ecology Research Centre, Plymouth University, United Kingdom) have reviewed the impact of debris on marine life, including seabirds, in the Marine Pollution Bulletin.  Their literature review shows that 10 species of ACAP-listed albatrosses and petrels, notably the Laysan Albatross Phoebastria immutabilis, on the IUCN threatened or near-threatened lists have been reported in the literature as being impacted by marine debris through entanglement or ingestion.  However, it is known that several of the remaining 20 ACAP-listed species, including the Critically Endangered Tristan Albatross Diomedea dabbenena, have also been impacted in this way.

The paper’s abstract follows:

“Marine debris is listed among the major perceived threats to biodiversity, and is cause for particular concern due to its abundance, durability and persistence in the marine environment.  An extensive literature search reviewed the current state of knowledge on the effects of marine debris on marine organisms.  340 original publications reported encounters between organisms and marine debris and 693 species.  Plastic debris accounted for 92% of encounters between debris and individuals. Numerous direct and indirect consequences were recorded, with the potential for sublethal effects of ingestion an area of considerable uncertainty and concern.  Comparison to the IUCN Red List highlighted that at least 17% of species affected by entanglement and ingestion were listed as threatened or near threatened.  Hence where marine debris combines with other anthropogenic stressors it may affect populations, trophic interactions and assemblages.”

Female Tristan Albatross Incubating on Gough Island, photograph by Marienne de Villiers

With thanks to Phelisa Hans for information.

Reference:

Gall, S.C. & Thompson, R.C. 2015.  The impact of debris on marine life.  Marine Pollution Bulletin doi:10.1016/j.marpolbul.2014.12.041.

John Cooper, ACAP Information Officer, 20 February 2015

Fredrik Haug (Marine and Environmental Sciences Centre, Universidade de Coimbra, Portugal) and colleagues have published this year in the journal Marine Biology on foraging differences in Cory’s Shearwaters Calonectris borealis breeding on Portugal’s Berlenga Island.

The paper’s abstract follows:

“Experience is believed to be an important factor determining the foraging success of animals, but there is limited knowledge on how foraging tactics differ among individuals, and on how individuals develop efficient foraging strategies.  Pelagic seabirds are some of the longest living organisms, and in several species, breeding is deferred far beyond their physical maturity.  The complex foraging skills needed to successfully rear a young is considered the most likely explanation for this life trait, making seabirds particularly interesting for the investigation of how foraging skills differ and develop through their life span.  In our study, the spatial distribution and foraging tactics of experienced and inexperienced males of a Procellariiform seabird species, the Cory’s shearwater (Calonectris borealis) breeding on the Portuguese continental shelf, were compared along three consecutive breeding seasons with ameliorating environmental conditions (from 2010 towards 2012).  Kernel overlaps of foraging areas and habitat modelling demonstrated that while experienced males showed high fidelity to shallow feeding grounds, inexperienced birds were more explorative and relied more on less-productive pelagic areas.  Our results seem to support the prediction that differences between experienced and inexperienced individuals are enhanced by food scarcity.  In fact, there was a higher spatial, trophic and behavioural segregation between both groups when environmental conditions were poor, which progressively diminished with improving environmental conditions.  Still, we cannot rule out the fact that inexperienced birds might be gaining experience with each breeding season and thus honing their foraging skills towards those of experienced individuals.”

Cory's Shearwaters, photograph by Paulo Catry

Reference:

Haug, F.D., Paiva, V.H., Werner, A.C. & Ramos, J.A. 2015.  Foraging by experienced and inexperienced Cory’s shearwater along a 3-year period of ameliorating foraging conditions.  Marine Biology 162: 649-660.

John Cooper, ACAP Information Officer, 20 February 2015

Gabriela Blanco (Centro Nacional Patagónico, Puerto Madryn, Argentina) and colleagues have written in the journal Estuarine, Coastal and Shelf Science on satellite tracking Southern Giant Petrels Macronectes giganteus at sea off the coast of Argentina.

The paper’s abstract follows:

“To study habitat use and at-sea movements of southern giant petrels (SGP) during non-breeding period, we deployed 15 satellite transmitters (six adults, nine juveniles) at Isla Arce and Isla Gran Robredo colonies in Patagonia, Argentina.  Birds were instrumented during 81.4 ± 37 days.  Adult birds used 74% of the Argentine shelf concentrating mainly at the shelf break, middle shelf waters, and the surroundings of the colony.  After fledging, juveniles spread to the Argentine, Uruguayan and Brazilian shelves within the South Atlantic.  Adults alternated at-sea excursions (12 ± 5 days) with periods at the colony of 3 ± 0.3 days.  Contrarily, juveniles moved first to the shelf break and then traveled [sic] northwards reaching the south of Brazil.  There was some spatial overlap between age classes, but only during the first 30 days after juveniles had fledged; thereafter there was not overlap between the areas used by both age classes.  The Argentine shelf is widely used by different species offering a suitable environment for foraging; this may be why adults SGP from Patagonian colonies spend all year-round within the Argentine shelf.  The identification of used areas of non-breeding SGP fills a gap in the species knowledge contributing not only to the preservation the species, but also to the management of marine areas globally recognized as important for many other Procellariiformes.”

Southern Giant Petrel, photograph by Juan Pablo Seco Pon

Click here to access a related paper by the senior author.

Reference:

Blanco, G.S.  & Quintana, F. 2014.  Differential use of the Argentine shelf by wintering adults and juveniles southern giant petrels,Macronectes giganteus, from Patagonia.    Estuarine, Coastal and Shelf Science 149: 151-159.

John Cooper, ACAP Information Officer, 19 February 2015