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Nestor Coria (Instituto Antártico Argentino, Buenos Aires, Argentina) and colleagues have published on the numbers of ACAP-listed Southern Giant Petrels Macronectes giganteus (and other birds) breeding on Laurie Island, South Orkney Islands in the 1990s in the latest issue of the journal Marine Ornithology.

Relevant information extracted from their paper follows.

"Censuses were made by direct counts of incubating or brooding birds for each breeding colony.  The two largest colonies were located on snow-free areas on the north coast.  At Watson Peninsula, the count of incubating of giant petrels in 1994/95 (235 active nests) was similar to that in 1993/94 (230 active nests), but the number of incubating birds decreased at Cape Geddes, where 184 active nests were counted compared with 228 in 1993/94.

The colonies of Southern Giant Petrels at Laurie Island, with 419 breeding pairs in 1995, represent over 12% of the total breeding population in the South Orkney Islands (3400 pairs, Patterson et al. 2008).  A comparison of the giant petrel breeding populations at Cape Geddes, from this study and earlier counts (Coria et al. 1996), shows that from 1985/86 to 1993/94, the breeding population increased by about 43%, with a slight decrease between 1993/94 and 1994/95.  For the other colony (Watson Peninsula) studied, the available data show no clear trends."

According to the ACAP Species Assessment for the Southern Giant Petrel (click here) the Cape Geddes and Watson Peninsula colonies supported 187 and 280 breeding pairs, respectively, in 2006.  This suggests that the Laurie Island population is a stable one with  range of 419 to 467 breeding pairs over the period 1993 to 2006.

Southern Giant Petrel breeding in Antarctica
Photograph by Markus Ritz

References:

Coria, N.R., Blendinger, P. & Montalti, D. 1996.  The breeding birds of Cape Geddes, Laurie Island, South Orkney Islands, Antarctica.  Marine Ornithology 24: 43-44.

Coria, N.R., Montalti, D., Rombola, E.F., Santos, M.M., Garcia Betoño, M.I. & Juares, M.A. 2011.  Birds at Laurie Island, South Orkney Islands, Antarctica: breeding species and their distribution.  Marine Ornithology 39: 207-213.

Patterson, D.L., Woehler, E.J., Croxall, J.P., Cooper, J., Poncet, S., Peter, H.-U., Hunter, S. & Fraser, W.R. 2008.  Breeding distribution and population status of the Northern Giant Petrel Macronectes halli and Southern Giant Petrel M. giganteus.  Marine Ornithology 36: 115-124.

John Cooper, ACAP Information Officer, 17 January 2012