Sebastian Jiménez (Laboratorio de Recursos Pelágicos, Dirección Nacional de Recursos Acuáticos, Montevideo, Uruguay) and colleagues have published in the journal Marine Biology on the importance of artificial food sources provided by fisheries to eight species of albatrosses and petrels.

The paper’s abstract follows:

“Although fisheries discards are recognized as a key food source for many seabirds, there have been few thorough assessments of their importance relative to natural prey, and of their influence on the trophic structure of pelagic seabird communities during the non-breeding period. Competition for resources in Procellariiformes appears to be reduced mainly by avoiding spatial overlap, which is supposed to influence diet composition. However, artificial food sources provided by fisheries might relax niche partitioning, increasing trophic niche overlap. Using bycaught birds from pelagic longline fisheries, we combined the conventional diet and stable isotope analyses to assess the importance of fishing discards in the diet of eight species of Procellariiformes. Both methods revealed the high contribution of trawl discards to the non-breeding diet of three neritic species and a moderate contribution in several other species; discards from pelagic and demersal longline fisheries were considerably less important. There was a clear contrast in diets of neritic vs. oceanic species, which are closely related taxonomically, but segregate at sea. Niche partitioning was less clear among neritic species. They showed an unexpectedly high level of diet overlap, presumably related to the large volume of trawl discards available. This is the first study combining the conventional diet and stable isotope analyses to quantify the importance of fishery discards for a community of non-breeding seabirds, and demonstrates how the super-abundance of supplementary food generates high levels of overlap in diets and allows the coexistence of species.”

Southern Royal Albatross, photograph by Barry Baker

With thanks to Sebastian Jiménez.

Reference:

Jiménez, S., Xavier, J.C., Domingo, A., Brazeiro, A., Defeo, O., Viera, M., Lorenzo, M.I. & Phillips, R.A. 2017. Inter-specific niche partitioning and overlap in albatrosses and petrels: dietary divergence and the role of fishing discards. Marine Biology doi:10.1007/s00227-017-3205-y plus supplementary information.

John Cooper, ACAP Information Officer, 10 August 2017

As previously reported in ACAP Latest News, ACAP will host a workshop on gadfly Pterodroma and other small burrowing petrels at the time of the Agreement’s meetings in Wellington, New Zealand next month. The Ninth Meeting of ACAP’s Advisory Committee (AC9) held in La Serena, Chile in May last year agreed to host the workshop with the main objective of advancing understanding about the best approaches for international cooperation in the conservation of the species to be considered.

Critically Endangered Galapagos Petrel Pterodroma phaeopygia, photograph by Eric Vanderwerf

An introduction to the workshop, along with its Terms of Reference, is now available online as AC10 Doc 14. Some suggestions for a way forward are also given as “starters” for the workshop’s discussions.

BirdLife International has prepared a summary document “Status, trends and conservation management needs of the Pterodroma and Pseudobulweria groups” along with an annexed spreadsheet of key data for each species that will be distributed in advance of the workshop. Following its presentation and discussion, the workshop may break into sub-groups to further its work.  A report of the meeting will be prepared for ultimate consideration by the next session of the ACAP Meeting of Parties, due to be held in 2018.

John Cooper, ACAP Information Officer, 09 August 2017

Airam Rodríguez (Department of Evolutionary Ecology, Estación Biológica de Doñana, Seville, Spain) and colleagues have published in the Journal for Nature Conservation on the effects of different types of night-time lights on Short-tailed Shearwaters Ardenna tenuirostris.

The paper’s abstract follows:

“The use of artificial light at night and its ecological consequences are increasing around the world. Light pollution can lead to massive mortality episodes for nocturnally active petrels, one of the most threatened avian groups. Some fledglings can be attracted or disoriented by artificial light on their first flights. Studies testing the effect of artificial light characteristics on attractiveness to seabirds have not provided conclusive results and there is some urgency as some endangered petrel species experience high light-induced mortality. We designed a field experiment to test the effect of three common outdoor lighting systems with different light spectra (high pressure sodium, metal halide and light emitting diode) on the number and the body condition of grounded fledglings of the short-tailed shearwater Ardenna tenuirostris. A total of 235 birds was grounded during 99 experimental hours (33 h for each treatment). 47% of birds was grounded when metal halide lights were on, while light emitting diode and high pressure sodium lights showed lower percentages of attraction (29% and 24%). Metal halide multiplied the mortality risk by a factor of 1.6 and 1.9 respectively in comparison with light emitting diode and high pressure sodium lights. No differences in body condition were detected among the birds grounded by the different lighting systems. We recommend the adoption of high pressure sodium lights (or with similar spectra) into petrel-friendly lighting designs together with other light mitigation measures such as light attenuation, lateral shielding to reduce spill and appropriate orientation.”

Short-tailed Shearwater at sea, photograph by Kirk Zufelt

Reference:

Rodríguez, A., Dann, P. & Chiaradia, A. 2017. Reducing light-induced mortality of seabirds: High pressure sodium lights decrease the fatal attraction of shearwaters. Journal for Nature Conservation 39: 68-72.

John Cooper, ACAP Information Officer, 08 August 2017

Gustavo Jiménez-Uzcátegui (Department of Sciences, Charles Darwin Foundation, Puerto Ayora, Galápagos, Ecuador) and colleagues have published  in the open access journal Marine Ornithology on heavy metals in feathers of three endemic or near-endemic species of Galápagos seabirds.

The paper’s abstract follows:

“Heavy metals are a threat to wildlife, and they have yet to be analyzed in seabirds from the Galápagos Archipelago. To gauge their prevalence in Galápagos seabird species, we collected and analyzed feather samples from Galápagos Penguins Spheniscus mendiculus, Flightless Cormorants Phalacrocorax harrisi, and Waved Albatross Phoebastria irrorata in seven different breeding areas in 2011 and 2012 as part of an ongoing mark-recapture study. The results showed that lead is higher in penguins and cormorants; cadmium was found to be below the limit for quantification in all our samples. The heavy metals recorded did not have a clear local source related to human activities, as breeding areas are not located near populated areas. Environmental media (soil, water), marine currents, and atmospheric deposition are possible sources.”

A Waved Albatross incubates its single egg

Reference:

Jiménez-Uzcátegui, G., Vinueza, R.L., Urbina, A.S., Egas, D.A., García, C., Cotín, J. & Sevilla, C. 2017. Lead and cadmium levels in Galapagos Penguin Spheniscus mendiculus, Flightless Cormorant Phalacrocorax harrisi, and Waved Albatross Phoebastria irrorata. Marine Ornithology 45: 159-163.

John Cooper, ACAP Information Officer, 07 August 2017