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

Mick Roderick (Shortland, New South Wales, Australia) has published in The Whistler on a White-bellied Sea-Eagle Haliaeetus leucogaster killing a Wedge-tailed Shearwater Puffinus pacificus.

The paper’s abstract follows:

“A White-bellied Sea-Eagle Haliaeetus leucogaster was observed taking a live Wedge-tailed Shearwater Ardenna pacifica that was completely submerged as the sea-eagle approached.  Although sea-eagles are known to hunt seabirds, there appears to be no published evidence of them taking a seabird that is submerged in Australia.  A sequence of images illustrates the scenario.”

Wedge-tailed Shearwater, photograph by Alan Burger

Reference:

Roderick, M. 2014.  Observation of a White-bellied Sea-Eagle taking submerged seabird prey.  The Whistler 8: 56-57.

John Cooper, ACAP Information Officer, 22 June 2015

Juan Pablo Seco Pon (Grupo Vertebrados. Instituto de Investigaciones Marinas y Costeras, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Mar del Plata, Argentina) and William Stein report in the Revista Brasileira de Ornitologia on the second photographically documented record of the ACAP-listed Spectacled Petrel  Procellaria conspicillata in Argentinian waters.

The paper’s abstract follows:

“The Spectacled Petrel Procellaria conspicillata is endemic to Inaccessible Island, in the Tristan da Cunha group (central South Atlantic).  The species is considered an occasional visitor to Argentina and there are few records of the species in national waters.  On 13 February 2014, two birds were observed (and photographed) 89 nautical miles southeast off Buenos Aires Province at 38°55'S, 56°00'W.  This record represents the second documented record of Spectacled Petrel for Argentina.”

Spectacled Petrel, photograph by Ross Wanless

Reference:

Seco Pon, J.P. & Stein III, W. 2015.  A second documented record of Spectacled Petrel Procellaria conspicillata in Argentine waters.  Revista Brasileira de Ornitologia 23: 29-30.

John Cooper, ACAP Information Officer, 21 June 2015