Now showing items 1-13 of 13

    • Activity seascapes highlight central place foraging strategies in marine predators that never stop swimming 

      Papastamatiou, Yannis; Watanabe, Yuuki; Demsar, Urska; Leos-Barajas, Vianey; Bradley, Darcy; Langrock, Roland; Weng, Kevin; Lowe, Christopher; Friedlander, Alan; Caselle, Jennifer (2018-06-21) - Journal article
      Background:  Central place foragers (CPF) rest within a central place, and theory predicts that distance of patches from this central place sets the outer limits of the foraging arena. Many marine ectothermic predators ...
    • Analysis of animal accelerometer data using hidden Markov models 

      Leos-Barajas, Vianey; Photopoulou, Theoni; Langrock, Roland; Patterson, Toby A.; Watanabe, Yuuki Y.; Murgatroyd, Megan; Papastamatiou, Yannis P. (2017-02) - Journal article
      1. Use of accelerometers is now widespread within animal biologging as they provide a means of measuring an animal's activity in a meaningful and quantitative way where direct observation is not possible. In sequential ...
    • An analysis of pilot whale vocalization activity using hidden Markov models 

      Popov, Valentin Mina; Langrock, Roland; De Ruiter, Stacy Lynn; Visser, Fleur (2017-01) - Journal article
      Vocalizations of cetaceans form a key component of their social interactions. Such vocalization activity is driven by the behavioral states of the whales, which are not directly observable, so that latent-state models are ...
    • Classifying grey seal behaviour in relation to environmental variability and commercial fishing activity - a multivariate hidden Markov model 

      van Beest, Floris M.; Mews, Sina; Elkenkamp, Svenja; Schuhmann, Patrick; Tsolak, Dorian; Wobbe, Till; Bartolino, Valerio; Bastardie, Francois; Dietz, Rune; von Dorrien, Christian; Galatius, Anders; Karlsson, Olle; McConnell, Bernie; Nabe-Nielsen, Jacob; Olsen, Morten Tange; Teilmann, Jonas; Langrock, Roland (2019-04-04) - Journal article
      Classifying movement behaviour of marine predators in relation to anthropogenic activity and environmental conditions is important to guide marine conservation. We studied the relationship between grey seal (Halichoerus ...
    • Double-observer line transect surveys with Markov-modulated Poisson process models for overdispersed animal availability 

      Borchers, David Louis; Langrock, Roland (2015-12) - Journal article
      We develop maximum likelihood methods for line transect surveys in which animals go undetected at distance zero, either because they are stochastically unavailable while within view or because they are missed when they are ...
    • Estimation and simulation of foraging trips in land-based marine predators 

      Michelot, Theo; Langrock, Roland; Bestley, Sophie; Jonsen, Ian D.; Photopoulou, Theoni; Patterson, Toby A. (2017-07) - Journal article
      The behavior of colony-based marine predators is the focus of much research globally. Large telemetry and tracking data sets have been collected for this group of animals, and are accompanied by many empirical studies that ...
    • Incorporating animal movement into distance sampling 

      Glennie, Richard; Buckland, Stephen Terrence; Langrock, Roland; Gerrodette, Tim; Ballance, Lisa; Chivers, Susan; Scott, Michael; Perrin, William (2017-09-08) - Journal article
      Distance sampling is a popular statistical method to estimate the density of wild animal populations. Conventional distance sampling represents animals as fixed points in space that are detected with an unknown probability ...
    • Incorporating animal movement with distance sampling and spatial capture-recapture 

      Glennie, Richard (University of St Andrews, 2018-12-06) - Thesis
      Distance sampling and spatial capture-recapture are statistical methods to estimate the number of animals in a wild population based on encounters between these animals and scientific detectors. Both methods estimate the ...
    • Markov-switching generalized additive models 

      Langrock, Roland; Kneib, Thomas; Glennie, Richard; Michelot, Théo (2017-01) - Journal article
      We consider Markov-switching regression models, i.e. models for time series regression analyses where the functional relationship between covariates and response is subject to regime switching controlled by an unobservable ...
    • Maximum likelihood estimation of mark-recapture-recovery models in the presence of continuous covariates 

      Langrock, Roland; King, Ruth (2013) - Journal article
      We consider mark-recapture-recovery (MRR) data of animals where the model parameters are a function of individual time-varying continuous covariates. For such covariates, the covariate value is unobserved if the corresponding ...
    • Modelling group dynamic animal movement 

      Langrock, Roland; Hopcraft, Grant; Blackwell, Paul; Goodall, Victoria; King, Ruth; Niu, Mu; Patterson, Toby; Pedersen, Martin; Skarin, Anna; Schick, Robert Schilling (2014-02) - Journal article
      1). Group dynamics are a fundamental aspect of many species' movements. The need to adequately model individuals' interactions with other group members has been recognized, particularly in order to differentiate the role ...
    • Statistical modelling of individual animal movement : an overview of key methods and a discussion of practical challenges 

      Patterson, Toby A.; Parton, Alison; Langrock, Roland; Blackwell, Paul G.; Thomas, Len; King, Ruth (2017-10) - Journal article
      With the influx of complex and detailed tracking data gathered from electronic tracking devices, the analysis of animal movement data has recently emerged as a cottage industry among biostatisticians. New approaches of ...
    • Using hidden Markov models to deal with availability bias on line transect surveys 

      Borchers, David Louis; Zucchini, Walter; Heide-Jørgensen, M.P.; Cañadas, A.; Langrock, Roland (2013) - Journal article
      We develop estimators for line transect surveys of animals that are stochastically unavailable for detection while within detection range. The detection process is formulated as a hidden Markov model with a binary ...