Population study of Gibsons Wandering Albatross Kath Walker Graeme - - PowerPoint PPT Presentation

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Population study of Gibsons Wandering Albatross Kath Walker Graeme - - PowerPoint PPT Presentation

Aug 20, 2023 665 likes •934 views

Population study of Gibsons Wandering Albatross Kath Walker Graeme Elliott Graham Parker Kalinka Rexer-Huber 3000 2500 2000 Number of adults 1500 1000 All as in 1991 adsurv as in 1991 500 Psuccess as in 1991 Breeding proportion as

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Population study of Gibson’s Wandering Albatross Kath Walker Graeme Elliott Graham Parker Kalinka Rexer-Huber

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1990 2000 2010 2020 2030 500 1000 1500 2000 2500 3000 All as in 1991 adsurv as in 1991 Psuccess as in 1991 Breeding proportion as in 1991 Status quo Number of adults

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Macquarie (Aus) Bounties Antipodes Campbell Aucklands Snares Chathams

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Macquarie (Aus) Bounties Antipodes Campbell Aucklands Snares Chathams

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× ×

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Wandering albatross breeding timetable

  • It takes a year to raise a chick

– Lay in January – Chicks fledge in the following December – February

  • In one visit to the island in Jan – Feb you can

collect all the data you need

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– Assess the nesting success of the previous year’s nests and band the chicks in the study area – Band and resight birds nesting in the study area for mark-recapture analysis – Mark and map all the nests – Count the nests in the census blocks – Sufficient data for a population model

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100 200 300 400 500 600 1998 2003 2008 2013 Number of nests Rhys's Ridge A to A Fly Square

Nest counts

2.7%

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Mark-recapture estimates of the number of breeders

200 250 300 350 400 450 500 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 Number of breeding birds Females Males

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0.1 0.2 0.3 0.4 0.5 0.6 0.7 1995 2000 2005 2010 2015 Proportion of females breeding

Proportion of females breeding

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Adult survival

0.8 0.9 1 1993 1998 2003 2008 2013 Annual survival male female

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Nesting success and productivity

20 40 60 80 100 120 140 160 10 20 30 40 50 60 70 80 90 1991 1996 2001 2006 2011 2016 Chicks produced in study area Nesting success (%) Nesting success Chicks produced

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0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

  • 1
  • 0.5

0.5 1 1.5 2 1993 1998 2003 2008 2013 Nesting succcess Southern Oscillation index

Southern Oscillation index vs Nesting success

La Niña - warmer Low nesting success High nesting success El Niño - cooler

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0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

  • 2.5
  • 2
  • 1.5
  • 1
  • 0.5

0.5 1 1.5 1995 2000 2005 2010 2015 Proportion breeding PDO

Pacific Decadal Oscillation index vs proportion breeding

PDO prop breeding

warmer cooler

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Geolocator dataloggers

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Before 2005 23 Males

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  • Lower survival
  • Lower productivity
  • Foraging more widely
  • Things are starting to look up.
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