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Productivity and survival within 2 declining populations of brown teal ( Anas chlorotis )

  • Publication Type

    Journal Article

  • Publication Year

    2001

  • Author(s)

    M. Williams

  • Journal Name

    Notornis

  • Volume, Issue

    48, 4

  • Pagination

    187-195

  • Article Type

    paper

Keywords

Anus chlorotis; breeding; brown teal; New Zealand; Northland; population; survival


Productivity and survival within 2 declining populations of brown teal ( Anas chlorotis )

Notornis, 48 (4), 187-195

M. Williams (2001)

Article Type: paper

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Brown teal (Anas chlorotis) populations at Clendon Cove and Tutaematai in Northland, New Zealand, declined catastrophically between 1993 and 1995, from 31 pairs to 1 and from 22 pairs to 8, respectively. Mean productivity was 1.8 fledglings pair1 in both populations. Fledgling survival was almost nil with only 1 of 51 identifiable fledglings surviving to recruit into 1 population. Almost all fledgling mortality occurred within 3 months of independence. Annual adult survival was 15% at Clendon Cove and 43% at Tutaematai and most deaths occurred in October-December, immediately after breeding. At Clendon Cove, significant mortality also occurred in autumn. Destruction of breeding and refuge habitat by cattle seeking moisture during periods of drought was identified as a significant cause of decline.