Improved methods for reducing translocation mortality and obtaining reliable population projections for reintroduction of the New Zealand Rifleman Acanthisitta chloris

Sarah Withers, Doug Armstrong, Tamsin Ward-Smith, Stuart Parsons, Mark E. Hauber

Research output: Contribution to journalArticle

Abstract

Despite many notable successes, the failure rate of animal translocations remains high. Conservation practitioners and reintroduction specialists have emphasised the need for ongoing documentation of translocation attempts, whether successful or not, including detailed methodologies and monitoring approaches. This study reports on the first translocation of the North Island subspecies of New Zealand's smallest bird, the endemic Rifleman Acanthisitta chloris granti. We describe an improved transfer methodology following recommendations arising from a previous translocation of South Island Rifleman Acanthisitta chloris chloris. Key modifications included a reduced capture window, shorter holding times, lack of extended aviary housing, and separation of territorial individuals during holding. Survival from capture to release increased from 52% to 97% using this new methodology. However, only 22% of 83 released birds were found in the reserve the next breeding season, resulting in an initial breeding population of only six males and five females. An integrated Bayesian analysis of three years of subsequent population data, including a population boost from a second translocation, projected a median decrease to 0-5 females over 10 years, but with 95% prediction intervals ranging from 0 to 33. These projections explicitly account for parameter uncertainty, as well as demographic stochasticity, and illustrate the need to do so when making inferences for small reintroduced populations.

Original languageEnglish (US)
JournalBird Conservation International
DOIs
StatePublished - Jan 1 2019
Externally publishedYes

Fingerprint

Chloris
reintroduction
translocation
mortality
methodology
parameter uncertainty
aviaries
birds
bird
Bayesian theory
Bayesian analysis
breeding season
breeding population
stochasticity
demographic statistics
subspecies
prediction
method
monitoring
breeding

ASJC Scopus subject areas

  • Ecology
  • Animal Science and Zoology
  • Nature and Landscape Conservation

Cite this

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title = "Improved methods for reducing translocation mortality and obtaining reliable population projections for reintroduction of the New Zealand Rifleman Acanthisitta chloris",
abstract = "Despite many notable successes, the failure rate of animal translocations remains high. Conservation practitioners and reintroduction specialists have emphasised the need for ongoing documentation of translocation attempts, whether successful or not, including detailed methodologies and monitoring approaches. This study reports on the first translocation of the North Island subspecies of New Zealand's smallest bird, the endemic Rifleman Acanthisitta chloris granti. We describe an improved transfer methodology following recommendations arising from a previous translocation of South Island Rifleman Acanthisitta chloris chloris. Key modifications included a reduced capture window, shorter holding times, lack of extended aviary housing, and separation of territorial individuals during holding. Survival from capture to release increased from 52{\%} to 97{\%} using this new methodology. However, only 22{\%} of 83 released birds were found in the reserve the next breeding season, resulting in an initial breeding population of only six males and five females. An integrated Bayesian analysis of three years of subsequent population data, including a population boost from a second translocation, projected a median decrease to 0-5 females over 10 years, but with 95{\%} prediction intervals ranging from 0 to 33. These projections explicitly account for parameter uncertainty, as well as demographic stochasticity, and illustrate the need to do so when making inferences for small reintroduced populations.",
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