Likelihood‐based photograph identification: Application with photographs of free‐ranging bison

ABSTRACT Using photographs to identify individual animals and monitor populations is becoming more common. However, photographic identification methods where measurements of morphological traits (e.g., horn length) are compared have received little attention. We present an approach for aiding with t...

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Main Authors: Jerod A. Merkle, Daniel Fortin
Format: Article
Language:English
Published: Wiley 2014-03-01
Series:Wildlife Society Bulletin
Subjects:
Online Access:https://doi.org/10.1002/wsb.382
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author Jerod A. Merkle
Daniel Fortin
author_facet Jerod A. Merkle
Daniel Fortin
author_sort Jerod A. Merkle
collection DOAJ
description ABSTRACT Using photographs to identify individual animals and monitor populations is becoming more common. However, photographic identification methods where measurements of morphological traits (e.g., horn length) are compared have received little attention. We present an approach for aiding with the identification of individual animals from photographs. The approach incorporates measurement data, metadata from photographs, and multiple sources of error, and calculates a matching score between pairs of photographs using a likelihood‐based algorithm. We tested and identified the false‐rejection error rate using 91 photographs, representing 33 known free‐ranging bison (Bison bison), and 117 simulated data sets with varying numbers of unique individuals, morphological measurements, and photograph error. We then used the approach to estimate the adult population size of bison in Prince Albert National Park, Canada, in 2011. For bison, the false‐rejection rate of our approach was 0.055. Using a Huggins closed population model with misidentification, we estimated 103 (95% CI = 82–130) and 46 (95% CI = 37–58) adult female and male bison, respectively. After incorporating field‐based calf‐ and juvenile‐to‐female ratios, we estimated 202 (95% CI = 171.6–231.4) bison. We found this estimate to be plausible using 2 minimum‐count aerial surveys conducted in March 2011 and 2012 for comparison. With our approach, researchers and managers can build capture histories of individuals, which can be used for studies of population dynamics and habitat selection. This approach can incorporate any morphological measurements extracted from photographs (e.g., coat color), making it robust to a variety of species and study systems. © 2013 The Wildlife Society.
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spelling doaj-art-8be2d2cdfa2a4f138fe1e63d62bdbf312024-12-16T12:17:05ZengWileyWildlife Society Bulletin2328-55402014-03-0138119620410.1002/wsb.382Likelihood‐based photograph identification: Application with photographs of free‐ranging bisonJerod A. Merkle0Daniel Fortin1Département de Biologie, Centre d'Étude de la ForêtUniversité LavalPavillon Alexandre Vachon 1045Avenue de la MédecineQuébecQCCanadaG1V 0A6Département de Biologie, Centre d'Étude de la ForêtUniversité LavalPavillon Alexandre Vachon 1045Avenue de la MédecineQuébecQCCanadaG1V 0A6ABSTRACT Using photographs to identify individual animals and monitor populations is becoming more common. However, photographic identification methods where measurements of morphological traits (e.g., horn length) are compared have received little attention. We present an approach for aiding with the identification of individual animals from photographs. The approach incorporates measurement data, metadata from photographs, and multiple sources of error, and calculates a matching score between pairs of photographs using a likelihood‐based algorithm. We tested and identified the false‐rejection error rate using 91 photographs, representing 33 known free‐ranging bison (Bison bison), and 117 simulated data sets with varying numbers of unique individuals, morphological measurements, and photograph error. We then used the approach to estimate the adult population size of bison in Prince Albert National Park, Canada, in 2011. For bison, the false‐rejection rate of our approach was 0.055. Using a Huggins closed population model with misidentification, we estimated 103 (95% CI = 82–130) and 46 (95% CI = 37–58) adult female and male bison, respectively. After incorporating field‐based calf‐ and juvenile‐to‐female ratios, we estimated 202 (95% CI = 171.6–231.4) bison. We found this estimate to be plausible using 2 minimum‐count aerial surveys conducted in March 2011 and 2012 for comparison. With our approach, researchers and managers can build capture histories of individuals, which can be used for studies of population dynamics and habitat selection. This approach can incorporate any morphological measurements extracted from photographs (e.g., coat color), making it robust to a variety of species and study systems. © 2013 The Wildlife Society.https://doi.org/10.1002/wsb.382Bison bisoncapture–mark–recapturecomputer‐assisted photographic‐identificationlikelihoodmisidentificationphotogrammetry
spellingShingle Jerod A. Merkle
Daniel Fortin
Likelihood‐based photograph identification: Application with photographs of free‐ranging bison
Wildlife Society Bulletin
Bison bison
capture–mark–recapture
computer‐assisted photographic‐identification
likelihood
misidentification
photogrammetry
title Likelihood‐based photograph identification: Application with photographs of free‐ranging bison
title_full Likelihood‐based photograph identification: Application with photographs of free‐ranging bison
title_fullStr Likelihood‐based photograph identification: Application with photographs of free‐ranging bison
title_full_unstemmed Likelihood‐based photograph identification: Application with photographs of free‐ranging bison
title_short Likelihood‐based photograph identification: Application with photographs of free‐ranging bison
title_sort likelihood based photograph identification application with photographs of free ranging bison
topic Bison bison
capture–mark–recapture
computer‐assisted photographic‐identification
likelihood
misidentification
photogrammetry
url https://doi.org/10.1002/wsb.382
work_keys_str_mv AT jerodamerkle likelihoodbasedphotographidentificationapplicationwithphotographsoffreerangingbison
AT danielfortin likelihoodbasedphotographidentificationapplicationwithphotographsoffreerangingbison