Seasonal variation in duck populations on the Waihopai River, Invercargill, New ZealandSubmitted by Briskie on Tue, 10/18/2011 - 13:10
|Title||Seasonal variation in duck populations on the Waihopai River, Invercargill, New Zealand|
|Publication Type||Journal Article|
|Year of Publication||2010|
|Authors||Wood, JR, Garden, CJ|
|Type of Article||Full article|
|Keywords||duck, hunting, mallard, refugia, seasonal population trends|
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.