Graham Parker (Parker Conservation, Dunedin, New Zealand) and colleagues have submitted a draft report to last month’s meeting of the Conservation Services Programme (CSP) of New Zealand’s Department of Conservation on a survey of ACAP-listed Grey Petrels Procellaria cinerea on Campbell Island.

The report’s abstract follows:

“Populations of grey petrels have declined due to both incidental capture in commercial fisheries and predation by introduced mammals at breeding sites.  In the New Zealand region grey petrels breed only on Campbell and Antipodes islands.  Rats were successfully eradicated from Campbell Island in 2001.  To investigate if the grey petrel population had expanded since the rat eradication, we defined the population’s spatial extent and produced the first quantitative population estimate on Campbell Island and surrounding islets.  We found no clear increase in the number of grey petrels breeding on Campbell Island relative to a historic, non-quantitative population estimate.  However, two of the four colonies we found are either recently established or previously went unidentified.  We estimated 90 pairs of breeding grey petrels from the four colonies located.  This underestimates the breeding population since work was conducted during the mid chick-rearing stage.  There may be grey petrels breeding on the off-shore islands that we could not survey, but if so, the number there would not significantly increase the island-wide population estimate.  The Campbell Island grey petrel breeding population remains small.  Our study provides a baseline for future population estimates of grey petrels on Campbell Island.”

A Grey Petrel in its burrow, photograph by Peter Ryan 

Click here to view a presentation on the above report.

With thanks to Barry Baker.

Reference:

Parker, G.C., Rexer-Huber, K. & Thompson, D. 2015.  Are Grey Petrels Returning to Campbell Island? Survey and Census 14 years after Rodent Eradication.  Report to the Department of Conservation.  Dunedin: Parker Conservation.  18 pp.

John Cooper, ACAP Information Officer, 08 July 2015

Andrew Reynolds (Rothamsted Research, Harpenden, UK) and colleagues have published in the Proceedings of the Royal Society B on the ability of the three species of Calonectris shearwaters to navigate at sea using their sense of smell.

The paper’s abstract follows:

“Homing studies have provided tantalizing evidence that the remarkable ability of shearwaters (Procellariiformes) to pinpoint their breeding colony after crossing vast expanses of featureless open ocean can be attributed to their assembling cognitive maps of wind-borne odours but crucially, it has not been tested whether olfactory cues are actually used as a system for navigation.  Obtaining statistically important samples of wild birds for use in experimental approaches is, however, impossible because of invasive sensory manipulation.  Using an innovative non-invasive approach, we provide strong evidence that shearwaters rely on olfactory cues for oceanic navigation.  We tested for compliance with olfactory-cued navigation in the flight patterns of 210 shearwaters of three species (Cory's shearwaters, Calonectris borealis, North Atlantic Ocean, Scopoli's shearwaters, C. diomedea Mediterranean Sea, and Cape Verde shearwaters, C. edwardsii, Central Atlantic Ocean) tagged with high-resolution GPS loggers during both incubation and chick rearing.  We found that most (69%) birds displayed exponentially truncated scale-free (Lévy-flight like) displacements, which we show are consistent with olfactory-cued navigation in the presence of atmospheric turbulence.  Our analysis provides the strongest evidence yet for cognitive odour map navigation in wild birds.  Thus, we may reconcile two highly disputed questions in movement ecology, by mechanistically connecting Lévy displacements and olfactory navigation. Our approach can be applied to any species which can be tracked at sufficient spatial resolution, using a GPS logger.”

Read more about this publication here.

Scopoli's Shearwater at sea, photograph by Pep Arcos

Reference:

Reynolds, A.M., Cecere, J.G., Paiva, V.H., Ramos, J.A., Focardi, S. 2015.  Pelagic seabird flight patterns are consistent with a reliance on olfactory maps for oceanic navigation.  Proceedings of the Royal Society B  DOI:10.1098/rspb.2015.0468.

John Cooper, ACAP Information Officer, 07 July 2015

Ben Dilley (Percy FitzPatrick Institute of African Ornithology, DST/NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa) and colleagues have published in the journal Antarctic Science on the deleterious effects of introduced House Mice Mus musculus on the breeding success of seven species of burrowing seabirds on Gough Island, including the ACAP-listed Grey Petrel Procellaria cinerea.

The paper’s abstract follows:

“Since 2004 there has been mounting evidence of the severe impact of introduced house mice (Mus musculus L.) killing chicks of burrow-nesting petrels at Gough Island.  We monitored seven species of burrow-nesting petrels in 2014 using a combination of infra-red video cameras augmented by burrowscope nest inspections.  All seven camera-monitored Atlantic petrel (Pterodroma incerta Schlegel) chicks were killed by mice within hours of hatching (average 7.2±4.0 hours) with an 87% chick failure rate (n=83 hatchlings).  Several grey petrel (Procellaria cinerea Gmelin) chicks were found with mouse wounds and 60% of chicks failed (n=35 hatchlings).  Video surveillance revealed one (of seven nests filmed) fatal attack on a great shearwater (Puffinus gravis O’Reilly) chick and two (of nine) on soft-plumaged petrel (Pterodroma mollis Gould) chicks.  Mice killed the chicks of the recently discovered summer-breeding MacGillivray’s prion (Pachyptila macgillivrayi Mathews), with a chick mortality rate of 82% in 2013/14 and 100% in 2014/15.  The closely-related broad-billed prion (P. vittata Forster) breeds in late winter and also had a chick mortality rate of 100% in 2014.  The results provide further evidence of the dire situation for seabirds nesting on Gough Island and the urgent need for mouse eradication.”

Grey Petrel, photograph by Peter Ryan

A one-minute video of an Atlantic Petrel chick being attacked by a mouse accompanies the publication.

With thanks to Alex Bond.

Reference:

Dilley, B.J., Davies, D., Bond, A.L. & Ryan, P.G. 2015.  Effects of mouse predation on burrowing petrel chicks at Gough Island.  Antarctic Science  DOI:http://dx.doi.org/10.1017/S0954102015000279.

John Cooper, ACAP Information Officer, 6 July 2015

Agathe Gérard (Institut Méditerranéen de Biodiversité et d'Écologie marine et continentale (IMBE), Aix-Marseille Université, Centre IRD de Nouméa, Nouvelle-Calédonie, France) and colleagues have published in the journal Austral Ecology on testing the ability of Wedge-tailed Shearwaters Puffinus pacificus to react to the odour of Ship or Black Rats Rattus rattus.

The paper’s abstract follows:

“Seabirds are particularly vulnerable to introduced alien mammalian predators, especially invasive rats, which are the main contributors to seabird extinction and endangerment in many places worldwide.  However, this appears context-dependent because, paradoxically, cases of apparent long-term coexistence between rats and some species of seabird have been reported for centuries, in various locations.  Among seabirds, procellariiforms are known to have developed a range of olfactory-driven behaviours, such as partner recognition and homing.  Olfaction could be an effective means of recognizing and thereafter avoiding invasive predators.  However, the role of olfaction in predation risk assessment has not yet been examined in any procellariiform.  Here, we investigated, through a Y-maze experiment, whether the wedge-tailed shearwater (Puffinus pacificus) avoided the odour of one of the most damaging alien predators on islands, the ship rat (Rattus rattus).  The experiment was conducted in different ecological contexts on three neighbouring islets off New Caledonia having different communities of invasive rats.  Contrary to our expectations, the wedge-tailed shearwater either did not detect or did not avoid the odour of the ship rat, despite about 175 years of coexistence between rats and shearwaters in New Caledonia.  These findings highlight the need for further investigations (across species, across sites) into the factors underpinning the paradox between high vulnerability and the surprising long-term coexistence between procellariid seabirds and alien invasive rats.”

Wedge-tailed Shearwater, photograph by Alan Burger

Reference:

Gérard, A., Jourdan, H., Millon, A. & Vidal, E. 2015.  Anti-predator behaviour in a procellariid seabird: Wedge-tailed shearwaters.  Austral Ecology DOI: 10.1111/aec.12252.

John Cooper, ACAP Information Officer, 05 July 2015