Volume 49 • Number 4 • August 2012 - 192.38.112.111

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Dispersal
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Data on movements of marked birds were used to estimate annual dispersal. Available
information suggests that approximately 73% of birds leave the general natal area annually
and 23% of these leave the wider flock region, so c. 17% of birds disperse annually
(Southgate 2002; Mooney & Pedler 2005). Dispersers moved an average of 44 km and up to
78 km (Southgate 2002). This high rate of dispersal supports our use of mark-recapturederived
survival estimates even though only a portion of the island is covered by the markrecapture
surveys. Our dispersal function had 17% of birds dispersing ≥28 km annually and
1% of the population (4 birds) dispersing 78 km annually (Fig. S1). We modelled dispersal as
a function of the distance between the centres of suitable habitat patches.
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dispersal ~ a = 0.8, b = 16.5, c = 1
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