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The Critically Endangered Balearic Shearwater Puffinus mauretanicus will be considered next month for listing within the Albatross and Petrel Agreement when the Fourth Session of ACAP's Meeting of Parties is held in Lima, Peru (see references listed below).

Although this small shearwater breeds only within Spain (on the Balearic Islands in the Mediterranean) its migrations take it into the Atlantic Ocean where it increasingly reaches the offshore waters of the United Kingdom in numbers.

Balearic Shearwater in the hand.  Photograph by Daniel Oro

"Record numbers of Balearic Shearwater arrive off southwest UK

The SeaWatch SW team recorded unprecedented numbers of Balearic Shearwaters off southwest UK this autumn.  The first significant influx occurred on 3 Sept with 101 seen off Start Point, and numbers then rapidly built up in western Lyme Bay with peak counts including 300+ of Berry Head on 5-6 Sept (part of a feeding flock of several thousand Manx Shearwaters), 376 off Orcombe Point on 11 Sept and a new Devon record of 383 moving southwest off Start Point on 12 Sept.  Many of these birds apparently continued westwards, as a total of 416 were seen moving west off Gwennap Head on 12-13 Sept.  Up to 200 Balearic Shearwaters continued feeding in Lyme Bay on 15-16 Sept (including counts of 50+ birds following trawlers off Berry Head) and it is possible that the westwards exodus of these birds contributed to a new Cornish record day count of 283 passing Gwennap Head on 18 Sept. Few remained in Lyme Bay after this date but good numbers continued to circulate off Gwennap Head, with three day counts of 150-200 in the period from 19-26 Sept.  It is likely that over 600 birds were present off Devon and Cornwall in mid-September, equating to about 2.5% of the World population and highlighting the increasing importance of this region for this Critically Endangered seabird.  A short note on this influx was published in British Birds in January 2012.

Balearic Shearwater recording in 2011

One of the main aims of SeaWatch SW has been to provide a focal point for land-based recording of the Critically Endangered Balearic Shearwater in UK and Irish waters.  Our partners at Marinelife are also leading intensive boat-based recording of this species in the English Channel.  Data collected between 2007 and 2010 are feeding into ongoing conservation efforts, for example SeaWatch SW have recently provided input to the updated Balearic Shearwater Species Action Plan and have submitted a report on the species status in UK waters to JNCC.  We are grateful to all observers who have provided us with records, and are now in a position to generate a research paper based on data collected in the last four years.  We will therefore not be collating UK and Irish records from 1 Jan 2011 onwards, but urge all observers to submit their records to Birdguides so they can be extracted and used in the future.

Balearic Shearwater tagging and tracking yields first results

The SeaWatch SW team (in collaboration with our partners at University of Oxford and Skua SLP Mallorca) has successfully tracked the year-round migration of the Balearic Shearwater for the first time.  The team deployed geolocators on 34 breeding birds in spring 2010, and recovered 27 of the devices in spring 2011.  The results are providing important insights into favoured feeding areas during the inter-breeding period.  GPS data have also provided information into feeding areas and flyways during the incubation phase.  A two-part report on the spring 2011 expedition can be found using the weblinks below, and the initial geolocator results have recently been submitted for publication to the online journal PLoS One.

http://www.birdguides.com/webzine/article.asp?a=2853

http://www.birdguides.com/webzine/article.asp?a=2855."

Selected References:

Arcos, J.M. (compiler) 2011.  International Species Action Plan for the Balearic Shearwater, Puffinus mauretanicus. Madrid: SEO/BirdLife & Cambridge: BirdLife International.  MoP4 Inf 02.  52 pp.

Darlaston, M. & Wynn, R.B. 2012. A record influx of Balearic Shearwaters in Devon and Cornwall.  British Birds 105: 37-38.

Spain 2012.  Proposed Amendment to Annex 1 of the Agreement on the Conservation of Albatrosses and Petrels (ACAP).  MoP4 Doc  16.  3 pp.

Spain 2012.  Species information - Balearic Shearwater, Puffinus mauretanicus.  MoP4 Inf 01.  11 pp.

With thanks to Ilka Win and Russell Wynn for information.

John Cooper, ACAP Information Officer, 5 March 2012, updated 7 March 2012