Pierre Defos du Rau, (Office National de la Chasse et de la Faune Sauvage, Station Biologique de la Tour du Valat, Le Sambuc, France) and colleagues report in the Journal of Ornithology on a new global estimate for Scopoli’s Shearwater Calonectris diomedea.

The paper’s abstract follows:

“Scopoli’s Shearwater (Calonectris diomedea) is a Procellariiform endemic to the Mediterranean Basin which is considered to be vulnerable in Europe due to recent local declines and its susceptibility to both marine and terrestrial threats. In the 1970s–1980s, its population size was estimated at 57,000–76,000 breeding pairs throughout the Mediterranean Basin, with the largest colony, estimated at 15,000–25,000 pairs, found on Zembra Island, Tunisia.  The objectives of our study were to re-estimate the size of the breeding population on Zembra Island, to reassess the global population size of the species, and to analyse the implications of these findings on status and conservation of this species in the Mediterranean.  Using distance sampling, we estimated the Zembra breeding population to be 141,780 pairs (95 % confidence interval 113,720–176,750 pairs).  A review of the most recent data on populations of this species throughout the Mediterranean Basin led us to estimate its new global population size at 141,000–223,000 breeding pairs.  Using the demographic invariant and potential biological removal approaches, we estimated the maximum number of adults which could be killed annually by all non-natural causes without causing a population decline to be 8800 (range 7700–9700) individuals, of which could be 3700 breeders.  Although these results are less alarming in the context of species conservation than previously thought, uncertainties associated with global population size, trends and major threats still raise questions on the future of this species.  More generally, we show how a monitoring strategy for a bird supposed to be relatively well known overall can be potentially misleading due to biases in survey design.  The reduction of such biases would therefore appear to be an unavoidable prerequisite in cryptic species monitoring before any reliable inference on the conservation status of the species can be drawn.”

Scopoli's Shearwater fledgling

Reference:

Defos du Rau, P. and 20 others 2015.  Reassessment of the size of the Scopoli’s Shearwater population at its main breeding site resulted in a tenfold increase: implications for the species conservation.  Journal of Ornithology DOI 10.1007/s10336-015-1187-4.

John Cooper, ACAP Information Officer, 01 April 2015

Yutaka Watanuki (Graduate School of Fisheries Sciences, Hokkaido University, Hokodate, Japan) and colleagues have written in in the Journal of Ornithology on mercury levels in Short-tailed Shearwaters Puffinus tenuirostris.

The paper’s abstract follows:

“We measured mercury concentrations ([Hg]) and nitrogen stable isotope ratios (δ¹⁵N) in the primary feathers of Short-tailed Shearwaters (Puffinus tenuirostris) that were tracked year-round.  The [Hg] were highest in 14 birds that used the Okhotsk and northern Japan Seas during the non-breeding period (2.5 ± 1.4 μg/g), lowest in nine birds that used the eastern Bering Sea (0.8 ± 0.2 μg/g), and intermediate in five birds that used both regions (1.0 ± 0.5 μg/g), with no effects of δ¹⁵N.  The results illustrate that samples from seabirds can provide a useful means of monitoring pollution at a large spatial scale.”

Short-tailed Shearwater, photograph by Mark Carey 

Reference:

Watanuki, Y., Yamamoto, T., Yamashita, A., Ishii, C., Ikenaka, Y., Nakayama, S.M.M., Ishizuka, M., Suzuki, Y., Niizuma, Y., Meathrel, C.E. & Phillips, R.A. 2015.  Mercury concentrations in primary feathers reflect pollutant exposure in discrete non-breeding grounds used by Short-tailed Shearwaters. Journal of Ornithology DOI .10.1007/s10336-015-1205-6.

John Cooper, ACAP Information Officer, 31 March 2015

April Hedd (Cognitive and Behavioural Ecology, Psychology Department, Memorial University, St. John’s, Newfoundland, Canada) and colleagues have reviewed seabird bycatch in eastern Canadian waters over a 13-year period in the journal Aquatic Conservation: Marine and Freshwater Ecosystems.

The paper’s abstract follows:

1. Seabird bycatch in commercial fisheries has been a growing conservation concern over the past 25 years.  Large-scale fisheries employing gears known to incidentally catch seabirds operate off eastern Canada, however, regional bycatch information is limited.
2. 2. Using data collected from 1998–2011 by observers onboard Canadian domestic and foreign vessels, fishery sectors and target fisheries taking seabirds were identified, as were the seabirds most frequently taken.  In addition, maps of seabird bycatch rates were used to identify localized areas where catch rates were high.
3. 3. Seabird bycatch was widespread.  Despite generally low observer coverage, > 5000 bird deaths were recorded; most observed mortalities occurred in gillnet and longline sectors during summer and autumn.  While the overall magnitude of seabird bycatch has likely decreased substantially since closure of the Atlantic cod Gadus morhua and Atlantic salmon Salmo salar gillnet fisheries in 1992, localized areas with high bycatch rates persist.
4. 4. For example, in Baffin Bay and Davis Strait, bycatch rates of northern fulmars Fulmarus glacialis were high in gillnet and longline fisheries targeting Greenland halibut Reinhardtius hippoglossoides near breeding colonies.  In offshore areas of the Grand Bank, catch rates of migrant shearwaters (Puffinus and Calonectris spp.) were high in deep-set gillnet fisheries for Greenland halibut and monkfish Lophius americanus during summer.  In inshore regions of eastern Newfoundland, gillnets set for Atlantic cod near breeding colonies resulted in high bycatch rates of murres Uria spp. and shearwaters during summer.  High bycatch rates were also observed in pelagic longline fisheries along the Scotian Shelf.
5. 5. While the observer data have highlighted several localized areas with high bycatch rates, information for inshore gillnet fisheries, which take seabirds but are poorly covered by the observer programme, and regional information on fishing effort must both be considered for comprehensive assessment of seabird risk areas and consequent management needs in eastern Canada.

Calonectris shearwater, photograph by John Graha

With thanks to Barry Baker for information.

Reference:

Hedd, A., Regular, P.M., Wilhelm, S.I., Rail, J.-F., Drolet, B., Fowler, M., Pekarik, C. & Robertson, G.J. 2015.  Characterization of seabird bycatch in eastern Canadian waters, 1998–2011, assessed from onboard fisheries observer data.  Aquatic Conservation: Marine and Freshwater Ecosystems  DOI: 10.1002/aqc.2551.

John Cooper, ACAP Information Officer, 30 March 2015

The breeding site of the recently described Bryan’s Shearwater Puffinus bryani has been suspected to be on Japan’s Ogasawara Islands where corpses of birds have been previously found (click here).

News is now in of the confirmation of breeding by the Critically Endangered shearwater with an incubating bird being discovered on Higashijima Island in the Ogasawaras, as described below by the Mainichi Japan of 25 March.

“A team of scientists has confirmed a nesting site of an endangered seabird species once thought to have gone extinct on the Ogasawara island chain, it has been learned -- the first time a nesting site of the species has ever been discovered.

The species, "Bryan's Shearwater," whose body length ranges between 27 and 30 centimeters, was believed to have gone extinct after it was last seen on Midway Atoll in 1991. Scientists conducted DNA testing on seabirds found on the Ogasawara Islands -- which have been recognized as a UNESCO world natural heritage site -- between 1997 and 2011, as their features matched those of the Bryan's Shearwater.

In 2012, it was confirmed that the birds were indeed members of the Bryan's Shearwater species. The Ministry of the Environment subsequently included the birds in the Red List as a critically endangered "IA" species.

In the latest discovery, scientists including Kazuto Kawakami, a senior researcher at the Forestry and Forest Products Research Institute, in Tsukuba, Ibaraki Prefecture, went ashore on several uninhabited islands of the Ogasawaras during the night, and searched for the rare bird by observing its high-pitched cry.

The researchers spotted a flock of 10 Bryan's Shearwaters on Higashijima island, approximately three kilometers east of Chichijima island, on Feb. 25-26. One of those birds was holding eggs inside of its nest.

"They were the only Bryan's Shearwaters found when we searched areas of some 3 hectares," Kawakami said. "We believe that the number of the species living on the islands is extremely small.  The seabirds may be surviving on other islands," he continued, "and we need to exterminate mice as well as alien plants, to avert the risk of losing these precious birds."

A Bryan's Shearwater takes shelter under rocks on Higashijima Island

Photograph courtesy of the Forestry and Forest Products Research Institute

For a similar news story from the Asahai Shimbun on the discovery click here.

For a press release (in Japanese) by the Forestry and Forest Products Research Institute with photographs of the birds and their breeding habitat on Higashijima Island click here.

Selected Literature:

Chikara, O. 2011.  Possible records of the newly described Bryan's Shearwater in Japan.  BirdingASIA 16: 86-88.

Kawakami, K., Eda, M., Horikoshi, K., Suzuki, H., Chiba, H. & Hiraoka, T. 2012.  Bryan's Shearwaters have survived on the Bonin Islands, Northwestern Pacific.  Condor 114: 507-512.

Pyle, P., David, R., Eilerts, B.D., Amerson, A.B., Borker, A. & Mckown, M. 2014.  Second record of Bryan’s Shearwater Puffinus bryani from Midway Atoll, with notes on habitat selection, vocalizations and at-sea distribution.  Marine Ornithology42: 5-8.

Pyle, P., J. Welch, A.J. & Fleischer, R.C. 2011.  A new species of shearwater (Puffinus) recorded from Midway Atoll, Northwestern Hawaiian Islands.  Condor113: 518-527.

John Cooper, ACAP Information Officer, 29 March 2015