Partial loss of migratory behaviour by Torresian Imperial-Pigeons Ducula spilorrhoa in Darwin, Northern Territory

Richard A. Noske, Amanda Lilleyman

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    The Northern Territory population of the Torresian Imperial-Pigeon Ducula spilorrhoa was once considered to be completely migratory, departing for New Guinea in February and returning to breed in August. However, reporting rates from Darwin suggest that since at least the early 1990s a substantial proportion of birds 'over-winter' in the region. We monitored an evening roost-site each month from May 2011 to August 2014, counting birds in 5-minute intervals as they arrived. Mean numbers were highest during the late wet-early dry season transition months (March through May) and lowest during the late dry-early wet season transition period (September through November), although the maximum number (1325 birds) was counted in June 2011, following the wettest wet season on record. These observations confirm that many Torresian Imperial-Pigeons do not migrate to New Guinea after the breeding season, but it is not yet known if any individual birds are long-term residents. It is possible that residency in the early dry season has evolved because of year-round availability of food resources in the urban environment but we were unable to test this hypothesis.

    Original languageEnglish
    Pages (from-to)206-210
    Number of pages5
    JournalAustralian Field Ornithology
    Volume33
    DOIs
    Publication statusPublished - Dec 2016

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    migratory behavior
    Northern Territory
    pigeons
    bird
    birds
    New Guinea
    wet season
    dry season
    roost site
    breeding season
    food availability
    breeds
    food
    loss
    winter
    resource
    testing

    Cite this

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    title = "Partial loss of migratory behaviour by Torresian Imperial-Pigeons Ducula spilorrhoa in Darwin, Northern Territory",
    abstract = "The Northern Territory population of the Torresian Imperial-Pigeon Ducula spilorrhoa was once considered to be completely migratory, departing for New Guinea in February and returning to breed in August. However, reporting rates from Darwin suggest that since at least the early 1990s a substantial proportion of birds 'over-winter' in the region. We monitored an evening roost-site each month from May 2011 to August 2014, counting birds in 5-minute intervals as they arrived. Mean numbers were highest during the late wet-early dry season transition months (March through May) and lowest during the late dry-early wet season transition period (September through November), although the maximum number (1325 birds) was counted in June 2011, following the wettest wet season on record. These observations confirm that many Torresian Imperial-Pigeons do not migrate to New Guinea after the breeding season, but it is not yet known if any individual birds are long-term residents. It is possible that residency in the early dry season has evolved because of year-round availability of food resources in the urban environment but we were unable to test this hypothesis.",
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    Partial loss of migratory behaviour by Torresian Imperial-Pigeons Ducula spilorrhoa in Darwin, Northern Territory. / Noske, Richard A.; Lilleyman, Amanda.

    In: Australian Field Ornithology, Vol. 33, 12.2016, p. 206-210.

    Research output: Contribution to journalArticleResearchpeer-review

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