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Abstract

An aerial photographic survey of the Southern Buller's Albatross Thalassarche bulleri bulleri population breeding on the Solander Islands / Hautere was undertaken on 09 March 2024, mid-way through the birds' incubation period. Overall, 6,761 individuals were counted: 6,215 (92%) on Great Solander and 546 (8%) on Little Solander. Of these, 4,213 were sitting on nests, 368 were partners to sitting birds, 573 were standing near empty nests, and 145 were apparently loafing. The status of the remaining 1,462 individuals (22% of the total) was uncertain. Assuming that their status was in the same proportions to those of the clearly observed birds, 1,164 were judged to be sitting on nests, giving an overall estimate of 5,377 occupied nests. This is 4% fewer birds at nests than recorded during the last survey in 2016, when 5,620 apparently breeding pairs were reported in a combined aerial survey and ground count of sitting birds. During the 2024 survey, a check of 54 occupied nests along seven short non-random transects found only 33 nests (62%) contained eggs. The remainder (21 nests, 38%) comprised birds sitting on empty nests. The status of these latter birds is unclear. They could be pre-breeders occupying sites prior to nesting for the first time; recent failed breeders that have not yet abandoned their nest; or established breeders forgoing breeding for some reason but still occupying their nest site. Overall, the numbers of apparently occupied nests suggest a decline in the number of nesting Southern Buller's Albatross since 2016. This conclusion is tentative, however, given the many uncertainties surrounding counts and their interpretation.

DOI

http://doi.org/10.5038/2074-1235.53.2.1666

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