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

José Seco (Department of Life Sciences, Marine and Environmental Sciences Centre (MARE), University of Coimbra, Portugal) and colleagues have published in the Journal of the Marine Biological Association of the United Kingdom on Short-finned Squid Illex argentinus taken by Grey-headed Thalassarche chrysostoma, Black-browed T. melanophris and Wandering Diomedea exulans Albatrosses.

The paper’s abstract follows:

“The diets of marine predators are a potential source of information about range shifts in their prey.  For example, the short-finned squid Illex argentinus, a commercially fished species on the Patagonian Shelf in the South Atlantic, has been reported in the diet of grey-headed, Thalassarche chrysostoma; black-browed, T. melanophris; and wandering, Diomedea exulans, albatrosses breeding at Bird Island, South Georgia (54°S 28°W) in the Southern Ocean.  Tracking data suggest that these birds may feed on I. argentinus while foraging in Southern Ocean waters during their breeding season.  This led to the hypothesis that I. argentinus may occur south of the Antarctic Polar Front.  To test this hypothesis, we used stable isotope analyses to assess the origin of I. argentinus.  We compared I. argentinus beaks from the diets of the three albatross species with beaks of cephalopod species endemic to the Patagonian Shelf and others from the Southern Ocean.  Our results show that I. argentinus from the diet of albatrosses at Bird Island have δ13C values in the range −18.77 to −15.28‰.  This is consistent with δ13C values for Octopus tehuelchus, a typical species from the Patagonian Shelf. In contrast, Alluroteuthis antarcticus, a Southern Ocean squid, has typically Antarctic δ13C in the range −25.46 to −18.61‰.  This suggests that I. argentinus originated from warmer waters of the Patagonian Shelf region.  It is more likely that the albatross species obtained I. argentinus by foraging in the Patagonian Shelf region than that I. argentinus naturally occurs south of the Antarctic Polar Front.”

Grey-headed Albatross, photograph by Mickey Reeves

Reference:

Seco, J., Daneria, G.A., Ceia, F,R. Vieira, R.P.,  Hill, S.J. & Xavier, J.C. 2015.  Distribution of short-finned squid Illex argentinus (Cephalopoda: Ommastrephidae) inferred from the diets of Southern Ocean albatrosses using stable isotope analyses.  Journal of the Marine Biological Association of the United Kingdom DOI: http://dx.doi.org/10.1017/S0025315415000752.

John Cooper, ACAP Information Officer, 04 July 2015