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Weights and measurements of Anas superciliosa in New Zealand

  • Publication Type

    Journal

  • Publication Year

    2017

  • Author(s)

    M. Williams

  • Journal Name

    Notornis

  • Volume, Issue

    64, 3

  • Pagination

    162-170

  • Article Type

    Paper

  • DOI

    https://doi.org/10.63172/558389eueyks

Keywords

Anas superciliosa; grey duck; measurements; New Zealand; weights


Weights and measurements of Anas superciliosa in New Zealand

Notornis, 64 (3), 162-170

M. Williams (2017)

Article Type: Paper

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Weights and body measurements from 258 male and 203 female adult (>1 year) and juvenile (<1 year) grey duck (Anas superciliosa), were collected from freshly-shot specimens in May 1974 and 1975 at sites in North Island, New Zealand. Mean weights of adult (1069 g) and juvenile (1035 g) males were significantly greater than those of adult (967 g) and juvenile (926 g) females. Assessment of body mass relative to skeletal size using a mass-size index (weight/tarsus2 ) did not detect any significant differences between any sex and age categories. Body measurements were of bill length and width, tarsus and middle-toe-and-claw lengths, and wing and tail lengths, and presented for each sex and age class. For every character measured, mean lengths for juvenile males were significantly longer than for juvenile females, and those for adult males significantly longer than for adult females. Within each sex, only mean wing and tail measurements from adults were significantly longer than those from juveniles. Significant differences in field weights and some body measurements between New Zealand and Australian A. superciliosa were identified.