Nesting requirements of the endangered Swift Parrot (Lathamus discolor)

Declines in avian biodiversity are being reported worldwide. A better understanding of the ecology of many species is fundamental to identifying and addressing threatening processes and developing effective mitigation measures. The Swift Parrot (Lathamus discolor) is listed as endangered and is an obligate migrant that breeds only in Tasmania, wintering in mainland Australia. The species nests in tree-hollows and forages primarily on flowers of the Tasmanian Blue Gum (Eucalyptus globulus) and Black Gum (Eucalyptus ovata) during the breeding season. Surveys for Swift Parrot nests conducted over three consecutive breeding seasons identified 130 Swift Parrot nests in 117 trees. Sites were between 12 and 130ha in area with up to 49 nests found at an individual site. Swift Parrot nest-trees were characterised as being large eucalypts (mean diameter at breast height≤105cm) with five or more potential hollows (mean≤8.6) and showing clear signs of senescence. Reuse of nests was uncommon over the 3 years and the infrequency of reuse was most likely related to poor flowering of Tasmanian Blue Gums around nesting sites in years following recorded nesting. To protect the species, conservation actions need to account for the spatiotemporal variation in the availability of Swift Parrot breeding habitat and recognise there may be several years between the use of a particular site. Given the number of nests found at individual sites this will require the management or reservation of suitable forest stands with old-growth characteristics across the landscape, rather than focussing on individual trees or historical nesting sites.