Saturday, September 19, 2020

Seasonal variation in duck populations on the Waihopai River, Invercargill, New Zealand

TitleSeasonal variation in duck populations on the Waihopai River, Invercargill, New Zealand
Publication TypeJournal Article
Year of Publication2010
AuthorsWood, JR, Garden, CJ
JournalNotornis
Volume57
Issue2
Pagination57-62
Type of ArticleFull article
Keywordsduck, hunting, mallard, refugia, seasonal population trends
Abstract

Seasonal variation in size of duck populations was examined using weekly surveys along a 1.5 km section of the Waihopai River, Invercargill, New Zealand, between Jul 1995 and Jul 1996. Six species were recorded: mallard (Anas platyrhynchos) (n = 8307), New Zealand shoveler (A. variegata) (n = 285), grey duck (A. superciliosa) (n = 36), paradise shelduck (Tadorna variegata) (n = 4), grey teal (A. gracilis) (n = 1), and New Zealand scaup (Aythya novaeseelandiae) (n = 1). Asynchronous seasonal trends were observed for mallard/grey duck and shoveler populations: mallard/grey duck numbers peaked during duck hunting season, whereas New Zealand shoveler peaked just prior, and declined during hunting season. A relatively constant rise in mallard/grey duck from Jan to late Jun highlights the difficulties in distinguishing the relative effects of post-breeding moult congregations vs. dispersal to refugia from hunting–related disturbance.

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