Susan Robinson (Invasive Species Branch, Department of Primary Industries, Parks, Water and Environment, Hobart, Australia) and colleagues have published in the New Zealand Journal of Ecology on the recovery of Tasman Island’s Short-tailed Shearwaters Puffinus tenuirostris and Fairy Prions Pachyptila turtur after the removal of feral Domestic Cats Felis catus.

The paper’s abstract follows:

"A restoration programme was initiated in 2008 in response to high levels of seabird predation by feral cats (Felis catus) at Australia’s largest fairy prion (Pachyptila turtur) colony on Tasman Island, Tasmania.  The primary knockdown involved aerial baiting with para-aminopropiophenone (PAPP) in meat baits. The efficacy of baiting was lower than expected resulting in trapping and hunting commencing earlier than planned.  Cats were successfully eradicated over two weeks.  Key to the success of the programme was the identification of a narrow window of low prey availability for cats.  Post-eradication monitoring of the two most common seabird species, fairy prions and short-tailed shearwaters (Ardenna tenuirostris), showed positive signs towards population recovery. Prion activity increased three-fold and shearwater breeding success increased.”

Short-tailed Shearwater

Click here for an earlier news item on conservation efforts on Tasman Island.

Reference:

Robinson, S., Gadd, L., Johnston, M. & Pauza, M. 2015.  Long-term protection of important seabird breeding colonies on Tasman Island through eradication of cats.  New Zealand Journal of Ecology 39.

John Cooper, ACAP Information Officer, 26 June 2015

The following news comes from the Seabirds.net member discussion group of the World Seabird Union.

“The first themed #seabirdersaturday on Twitter is this upcoming Saturday.  It is chaired by José Manuel Arcos (@PepArcos) who will be around 1400-1600 GMT to lead the conversation and answer questions that people might have.

Seabird bycatch is regarded as one of the major threats for many seabird species, particularly albatrosses, petrels and shearwaters throughout the world.  For years research and conservation action were focused in longline fleets operating in the southern Oceans, where many albatross species were experiencing sharp declines due to this factor of added mortality.  However, there’s increasing evidence that the problem extends to other regions and involves several gear types.

One of the bycatch hotspots worldwide appears to be the Mediterranean, although the information there is still patchy and precludes a proper assessment.  The basin is particularly sensitive from a seabird point of view, since diversity is high, with quite a few endemic taxa, and populations are relatively small.

Of the seabirds of conservation concern, two species deserve particular attention, the Balearic shearwater Puffinus mauretanicus (Critically Endangered) and the Yelkouan shearwater P. yelkouan (Vulnerable).  Both are endemic to the Mediterranean, with small global populations and sharp declining trends that could lead to their extinction in the near future. Although they are affected by introduced predators and other threats in their colonies, the major drivers of their decline seem to occur at sea, and bycatch postulates itself as the most important of them, particularly on longlines.  Other endemic taxa are also regularly affected by longline bycatch, including Scopoli’s shearwater Calonectris diomedea and Audouin’s gull Larus audouinii.

But most of the information on bycatch comes from the western Mediterranean, with recent work also conducted in the central (Malta) and eastern basin (Greece).  Information regarding other gears, such as set nets (that might impact the Mediterranean shag Phalacrocorax aristotelis desmarestii), purse-seines and trawlers, is also very limited. BirdLife is trying to fill these gaps with its new Seabird Task Force, but the task ahead is huge.

Next #seabirdersaturday we want to discuss on the topic of seabird bycatch in the Mediterranean and try to put in common information from ornithologists all around the basing, as well as beyond.

Join the conversation on 27 June 1400-1600 GMT, and please help spread the word!”

A Yelkouan Shearwater gets caught on a longline, photograph by Vero Cortes

The Balearic Shearwater is an ACAP-listed species.  The Yelkouan and Cory’s Shearwaters have been identified by ACAP as potential candidates for listing within the Agreement.

The World Seabird Union's mission is to place seabird research, management, and conservation into a worldwide perspective.  Its vision is to aid in creating global partnerships that will continue into the future by sharing research, knowledge, and ideas on a global level.

John Cooper, ACAP Information Officer, 25 June 2015

Lise Ruffino (Section of Ecology, Department of Biology, University of Turku, Finland) and colleagues have assessed the impacts of rodents on island bird populations, including procellariiform seabirds, such as the ACAP potential candidate and Vulnerable Yelkouan Shearwater Puffinus yelkouan, in the journal Wildlife Research.

The paper’s abstract follows:

“Bird conservation is nowadays a strong driving force for prioritising rodent eradications, but robust quantitative estimates of impacts are needed to ensure cost-effectiveness of management operations.  Here, we review the published literature to investigate on what methodological basis rodent effects on island bird communities have been evaluated for the past six decades.  We then discuss the advantages and limitations of each category of methods for the detection and quantification of impacts, and end with some recommendations on how to strengthen current approaches and extend our knowledge on the mechanisms of impacts.  Impact studies (152 studies considered) emphasised seabirds (67%), black rats (63%) and the Pacific Ocean (57%).  Among the most commonly used methods to study rodent impacts on birds were the observation of dead eggs or empty nests while monitoring bird breeding success, and the analyses of rodent diets, which can both lead to misleading conclusions if the data are not supported by direct field evidence of rodent predation.  Direct observations of rodent–bird interactions (19% of studies) are still poorly considered despite their potential to reveal cryptic behaviours and shed light on the mechanisms of impacts.  Rodent effects on birds were most often measured as a change or difference in bird breeding parameters (74% of studies), while estimates of bird population growth rates (4%) are lacking.  Based on the outcomes of this literature review, we highlight the need for collecting unbiased population-level estimates of rodent impacts, which are essential prerequisites for predicting bird population growth scenarios and prioritising their conservation needs.  This could be achieved by a more systematic integration of long-term monitoring of bird populations into rodent management operations and modelling bird population dynamics.  We also strongly recommend including various complementary methods in impact assessment strategies to unravel complex interactions between rodents and birds and avoid faulty evidence.  Finally, more research should be devoted to a better understanding of the cases of non-impacts (i.e. long-term coexistence) and those impacts mediated by mechanisms other than predation and ecosystem-level processes.”

Yelkouan Shearwater, photograph by Matthew Borg Cardona

Reference:

 Ruffino, L., Zarzoso-Lacoste, D. & Vidal, E. 2015.  Assessment of invasive rodent impacts on island avifauna: methods, limitations and the way forward.  Wildlife Research 42: 185-195.

John Cooper, ACAP Information Officer, 24 June 2015

The Vulnerable Pink-footed Shearwater Puffinus creatopus is a recently listed ACAP species.  A breeding endemic to Chile it migrates to the northern hemisphere – as far as Canadian waters - after breeding.  Over recent years the species’ trans-equatorial migration routes have been studied (click here and here).

This year in April 10 breeding Pink-footed Shearwaters were fitted with solar-powered satellite trackers on Chile’s Isla Mocha.  Four of the birds are currently off the coast of Peru, and six have already crossed the Equator into Mexican waters on their way north, as of 22 June.

One of the 10 shearwaters has shown a previously undescribed behaviour in its migration, entering into offshore pelagic waters off the coast of Mexico.

Follow the shearwaters' daily progress here.

Pink-footed Shearwater, photograph by Peter Hodum

Tracking map for 22 June courtesy of Oikonos Ecosystem Knowledge

The tracking study is a project of the U.S. Geological Survey and Oikonos Ecosystem Knowledge.

John Cooper, ACAP Information Officer, 23 June 2015