J.M. “Pep” Arcos and colleagues have written an article in the July 2015 issue of BirdLife Europe’s electronic newsletter Birdseye that considers the conservation needs of the ACAP-listed and Critically Endangered Balearic Shearwater Puffinus mauretanicus.

A paragraph from their article follows:

 “Balearic Shearwater may not be the most colourful bird, it’s rather brownish and could be mistaken for a gull by an untrained eye, but it’s special. Only found as a breeder in the western Mediterranean’s Balearic Islands where it nests in caves, crevices and under rock boulders in inaccessible sea cliffs and small islets.  We think there are just a little over 3,000 breeding pairs, and maybe a global population of about 25,000 individuals.  It’s long lived, most likely some birds live over 30 years though we have no sound data on this, it begins mating at 3 years of age, and lays a single egg per year.  Losing adult birds is therefore of serious concern, as they are not quickly or easily replaced.  Unfortunately, the population has been steadily declining as a consequence of several threats, particularly fisheries bycatch at sea and predation by invasive species on land. This trend is alarming and scientists say it could become extinct in slightly over half a century.”

A Balearic Shearwater at its cave breeding site, photograph by Miguel McMinn 

Click here for an earlier account on the Balearic Shearwater in ACAP Latest News and here to access the International Action Plan for the species.

Reference:

Arcos, J.M., David García, D., Oro, D., Genovart, M.& Louzao, M. 2015.  Keeping an eye on Balearic Shearwater.  Birdseye 22(7).

John Cooper, ACAP Information Officer, 08 August 2015

Stephen Totterman (Empire Vale, New South Wales, Australia) has published in the New Zealand journal Notornis on recording calls of burrow-breeding Wedge-tailed Shearwaters Puffinus pacificus.

The paper’s abstract follows:

“Calls and playback-response behaviour of breeding wedge-tailed shearwaters (Puffinus pacificus) were studied at Muttonbird Island, Coffs Harbour, New South Wales, Australia.  Burrow calls were recorded from 45 females and 60 males.  Male calls averaged higher in fundamental frequency and longer in note lengths than female calls, although ranges overlapped.  Playback experiments demonstrated sexual recognition, with incubating females mostly responding to female playbacks.  Males responded to both female and male calls.  Ratios of between- to within-subject variation suggested that individual vocal signatures could be encoded in timing and some frequency parameters.  Playback experiments demonstrated a “dear enemy” effect, where shearwaters in burrows were more responsive to stranger rather than neighbour calls.  Wedge-tailed shearwater calls are informative and further studies are encouraged for other southern hemisphere breeding shearwaters.”

Wedge-tailed Shearwater, photograph by Alan Burger

Click here for a related paper by Stephen.

Reference:

Totterman, S.L. 2015.  Sexual and individual differences in wedge-tailed shearwater (Puffinus pacificus) burrow calls and vocal recognition.  Notornis 61: 121-130.

John Cooper, ACAP Information Officer, 07 August 2015

Claudia Mischler (Wildlife Management International Limited) and colleagues have published in the New Zealand journal Notornis on sexing ACAP-listed Black Petrels Procellaria parkinsoni utilizing morphometrics.

The paper’s abstract follows:

“Discriminant function analysis (DFA) is widely used to determine sex in the field from morphological measurements of bird species with monomorphic plumage.  Sexual dimorphism was examined in black petrels (Procellaria parkinsoni) using 7 external measurements of adult birds breeding on Great Barrier Island, New Zealand.  Males were significantly larger than females in absolute values of all measurements except for tarsus.  Two stepwise DFA models were developed.  The first used all 7 parameters, while the second model used only 6 parameters in order to increase sample size.  Model one and two showed an 88 and 82% classification success, respectively, most likely due to the high overlap in measurements between males and females.  These canonical functions were not accurate enough for field surveys, but may be improved using a larger and more representative sample size.”

Black Petrel, photograph by New Zealand Department of Conservation

Reference:

Mischler, C.P.,Bell, E.A.,Landers, T.J. & Dennis, T.E. 2015.  Sex determination of black petrels (Procellaria parkinsoni) using morphometric measurements and discriminant function analysis.  Notornis 62: 57-62.

John Cooper, ACAP Information Officer, 06 August 2015

Claudia Mischler (Wildlife Management International Limited) and colleagues have published in the New Zealand journal Notornis on variation in bycaught White-chinned Petrels Procellaria aequinoctialis in New Zealand waters.

The paper’s abstract follows:

“Discriminant function analysis (DFA) was used to determine gender and geographic variation in the morphometrics of white-chinned petrels (Procellaria aequinoctialis) measured from fisheries bycatch in New Zealand.  Samples were divided into 5 clusters based on capture location.  A DFA model was created using adult breeding birds presumed to be from the 2 main locations at the Auckland Islands and Antipodes Islands.  Geographic variation in head and bill, skull width, culmen, culmen depth at base, culmen width at base, right and left mid-toe and claw, tail, and right and left wing was found between birds presumed to be from the ‘Auckland’ and ‘Antipodes’ clusters, with ‘Antipodes’ birds being generally larger than ‘Auckland’ birds.  Gender variation in head and bill, skull width, culmen, culmen depth at base, culmen width at base, minimum bill depth, right and left mid-toe and claw, right wing, right and left tarsus existed for ‘Auckland’ birds.  Gender variation in head and bill, skull width, culmen, culmen depth at base, culmen width at base, minimum bill depth, right and left mid-toe and claw, and tail existed for ‘Antipodes’ birds.  Birds in the other 3 clusters were classified as originating from the Auckland Islands or Antipodes Islands.  The clustering suggested that birds from the Auckland Islands tended to forage mostly north and west, whereas birds from the Antipodes Islands foraged mostly towards the north.  There were large overlaps at Puysegur Point and particularly the Chatham Rise of birds from both breeding locations.  This study shows the usefulness of bycatch necropsies, and emphasises the need for further studies in geographic variation and sexual dimorphism at all New Zealand breeding locations.”

White-chinned Petrels, photograph by Ben Phalan

Reference:

Mischler, C.P., Robertson, C.J.R. & Bell, E.A. 2015.  Gender and geographic variation in morphometrics of white-chinned petrels (Procellaria aequinoctialis) in New Zealand and their foraging activities as determined from fisheries bycatch.  Notornis 62: 63-70.

John Cooper, ACAP Information Officer, 05 August 2015