Counting Nellies: the Southern Giant Petrels of Marion Island

Whole-island counts of breeding albatrosses and giant petrels are made annually at South Africa's Marion Island, one of the Prince Edward Islands in the southern Indian Ocean.  For some species counts are made at both incubation and large-chick times, so that both trends over years and a measure of breeding success can be ascertained.

The counts, carried out as part of South Africa's contribution to the work of the Albatross and Petrel Agreement, require researchers on the island to make extended field trips, walking round the whole island's coastline, staying overnight in field huts for periods of up to a week or more at a time.

The results for the 2001/11 breeding season for ACAP-listed Southern Giant Petrels Macronectes giganteus are now available.  A total of 1743 occupied nests (with incubating birds) was counted in 65 individual colonies during the month of October last year.  In February this year 908 large chicks were counted, given an estimate of breeding success of 52.1% (experience has shown that by this time few large chicks die before fledging).

Counts were undertaken by the all-woman team of Linda Clokie and Yolokasi Galada, with help from Mia Cerfonteyn, working for a project jointly managed by the Percy FitzPatrick Institute, University of Cape Town and Branch Oceans & Coasts of the South African Department of Environmental Affairs.

Numbers of Southern Giant Petrels at Marion have been reasonably stable in recent years, following a marked drop in the second half of the 1990s from 2500-3000 pairs in the 1980s and early 1990s (Ryan et al. 2009).

Visit http://www.oceanlight.com/log/southern-giant-petrel-macronectes-giganteus-southern-ocean.html to view recently-posted pictures of flying Southern Giant Petrels.

Click here for news of the 2011 Marion Island count of ACAP-listed Wandering Albatrosses Diomedea exulans.

Reference:

Ryan, P.G., Jones, M.G.W., Dyer, B.M., Upfold, L. & Crawford, R.J.M. 2009.  Recent population estimates and trends in numbers of albatrosses and giant petrels breeding at the sub-Antarctic Prince Edward Islands.  African Journal of Marine Science 31: 409-417.

With thanks to Yolokasi Galada for information.

John Cooper, ACAP Information Officer, 11 March 2011

The Agreement on the
Conservation of Albatrosses and Petrels

ACAP is a multilateral agreement which seeks to conserve listed albatrosses, petrels and shearwaters by coordinating international activity to mitigate known threats to their populations.

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