Wednesday, July 26, 2017

Dispersal of southern black-backed gulls (Larus dominicanus dominicanus) banded in Canterbury, New Zealand, 1959-1993

TitleDispersal of southern black-backed gulls (Larus dominicanus dominicanus) banded in Canterbury, New Zealand, 1959-1993
Publication TypeJournal Article
Year of Publication2013
AuthorsRowe, LK
JournalNotornis
Volume60
Issue2
Pagination134-142
Type of ArticleFull article
KeywordsAshley River, banding, dispersal, Larus dominicanus dominicanus, Motunau Island, recoveries, Southern Black-backed Gull, Waimakariri River
Abstract

A total of 3455 southern black-backed gull (Larus dominicanus dominicanus) chicks were banded at 4 Canterbury localities between 1959 and 1993: Ashley River 1239; Waimakariri River 219; Motunau Island 1997. Only 180 (5.2%) of these chicks were recovered, 3.0% of the river colony chicks and 6.9% of the Motunau Island chicks. Three-quarters of recoveries were in rural environments with most others on the coast; 14 had been shot or trapped and killed. The oldest recovery from the river colonies was 6.1 years old but this may be an underestimate due to wear and loss of aluminium bands used early in the study period; Motunau Island birds were found up to 25.7 years after banding. Birds dispersed widely from the Wairarapa to Southland travelling up to 486 km. Recoveries of first year birds off-colony averaged 96 km which is more than the older birds, 54 km; 7/10 birds that travelled over 200 km were first year birds. On average, Motunau Island birds were found further from the natal colony than birds from the river colonies. My results indicate that dispersal distances and direction of black-backed gulls are variable, and that dispersal can occur between the North and South Islands.

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