Peggy Ostrom (Department of Zoology, Michigan State University, East Lansing, Michigan, USA) and colleagues have published in the journal Oecologia on variations in hydrogen isotope values in North Pacific albatrosses and petrels.

The paper’s abstract follows:

“Hydrogen isotopes have significantly enhanced our understanding of the biogeography of migratory animals.  The basis for this methodology lies in predictable, continental patterns of precipitation δD values that are often reflected in an organism’s tissues.  δD variation is not expected for oceanic pelagic organisms whose dietary hydrogen (water and organic hydrogen in prey) is transferred up the food web from an isotopically homogeneous water source.  We report a 142 ‰ range in the δD values of flight feathers from the Hawaiian petrel (Pterodroma sandwichensis), an oceanic pelagic North Pacific species, and inquire about the source of that variation.  We show δD variation between and within four other oceanic pelagic species: Newell’s shearwater (Puffinus auricularis newellii), Black-footed albatross (Phoebastria nigripes), Laysan albatross (Phoebastria immutabilis) and Buller’s shearwater (Puffinus bulleri).  The similarity between muscle δD values of hatch-year Hawaiian petrels and their prey suggests that trophic fractionation does not influence δD values of muscle.  We hypothesize that isotopic discrimination is associated with water loss during salt excretion through salt glands.  Salt load differs between seabirds that consume isosmotic squid and crustaceans and those that feed on hyposmotic teleost fish.  In support of the salt gland hypothesis, we show an inverse relationship betweenδD and percent teleost fish in diet for three seabird species.  Our results demonstrate the utility of δD in the study of oceanic consumers, while also contributing to a better understanding of δD systematics, the basis for one of the most commonly utilized isotope tools in avian ecology.”

Reference:

Ostrom, P.H., Wiley, A.E.,Rossman, S., Stricker, C.A. & James, H.F. 2014.  Unexpected hydrogen isotope variation in oceanic pelagic seabirds.  Oecologia 175: 1227-1235.

John Cooper, ACAP Information Officer, 06 August 2014

Ahmed Taibi (Department of Agronomy, Aboubekr Belkaid University of Tlemcen, Algeria) and colleagues write in the journal Advances in Environmental Biology on the Scopoli’s Shearwaters Calonectris diomedea that breed on rat-free Rachgoun Island in the Mediterranean.

The paper’s abstract follows:

Rachgoun Island is one of the largest islands of Algeria with more than 26 hectares.  It houses one of the largest colonies of Cory’s shearwater Calonectris diomedea in Algeria.  A shipping of four days (21 to 25 June 2013) followed by several periodic visits were organized on the island and have as objectives to study the reproduction and distribution of this rare species.  The reproductive success is high because of the absence of the rats on the island.  30 nests were studied by reason of one egg per nest.  The nests are dug in the ground with an average opening of 26.9 cm and a total length equal to 95.3 cm.  The egg is deposited to an average of 67.3 cm from the opening.  Nests are placed at a distance of 26.1 m from the sea and at an altitude of 20.9 m. Eggs whitish color have the greatest length of 67 mm and the largest width of 46.3 mm.  The average of volume and weight of eggs are respectively 68.58 cm³ and 62.2 g.

Cory's/Scopoli's Shearwater, photograph by John Graham

Reference:

Taibi, A., Ghermaoui, M., & Oubaziz, B. 2014.  First study of the reproduction of Cory's shearwater Calonectris diomedea (Procellariidae, Aves) at the Rachgoun Island (Beni Saf, Algeria).  Advances in Environmental Biology 8: 15-20.

John Cooper, ACAP Information Officer, 05 August 2014

Dani López-Velasco has published on-line a report of a Birdquest tour to Australian and New Zealand sub-Antarctic islands last austral summer in which 48 species of procellariiform seabirds were seen (click here).

Over 18 days aboard the Spirit of Enderby visits were made to the Snares, the Auckland Islands, Macquarie Island, Campbell Island, the Antipodes Islands, the Bounty Islands and the Chatham Islands.  The detailed report contains accounts and photographs of 12 species of ACAP-listed and five species of ACAP-listed petrels: over half the total number of ACAP listed species.

Southern Royal Albatross, photograph by Aleks Terauds

Reference:

López-Velasco, D.  2014.  BirdQuest Tour Report.  The Subantarctic islands of New Zealand & Australia 14 November – 2 December 2013.  BirdQuest.  47 pp.

John Cooper, ACAP Information Officer, 04 August 2014

The Endangered Newell’s Shearwater Puffinus newelli and Vulnerable Hawaiian Petrel Pterodroma sandwichensis are both endemic to the USA’s Hawaiian Islands.  Kauai is home to 90% of the World’s population of the shearwater, as well as holding important populations of the petrel.

On Kauai both species are under threat from introduced rats Rattus spp..  The Kauai Endangered Seabird Recovery Project has filmed rats entering burrows: “KESRP is using infrared cameras to monitor the secret lives of endangered Newell’s Shearwater and Hawaiian Petrels in remote locations of Hono o Na Pali Natural Area Reserve and Upper Limahuli Preserve.  Last year, at one specific Na Pali Coast site, rats alone killed 20 percent of nesting chicks” (click here).

Newell's Shearwater, photograph by Eric Vanderwerf

Kauai’s burrowing seabirds are also affected by feral Domestic Cats Felis catus.

John Cooper, ACAP Information Officer, 03 August 2014