Quantifying the errors in animal contacts recorded by proximity loggers

Federico Ossi, Stefano Focardi, Bryony Tolhurst, G.P. Picco, Amy Murphy, Davide Molteni, Noemi Giannini, Jean-Michel Gaillard, Francesca Cagnacci

Research output: Contribution to journalArticlepeer-review


Automated contact detection by means of proximity loggers permits the measurement of encounters between individuals (animal-animal contacts) and the time spent by individuals in the proximity of a focal resource of interest (animal-fixed logger contacts). The ecological inference derived from contact detection is intrinsically associated with the distance at which the contact occurred. But no proximity loggers currently exist that record this distance and therefore all distance estimations are associated with error. Here we applied a probabilistic approach to model the relationship between contact detection and inter-logger distance, and quantify the associated error, on free-ranging animals in semi-controlled settings. The probability of recording a contact declined with the distance between loggers, and this decline was steeper for weaker radio transmission powers. Even when proximity loggers were adjacent, contact detection was not guaranteed, irrespective of the radio transmission power. Accordingly, the precision and sensitivity of the system varied as a function of inter-logger distance, radio transmission power, and experimental setting (e.g., depending on animal body mass and fine-scale movements). By accounting for these relationships, we were able to estimate the probability that a detected contact occurred at a certain distance, and the probability that contacts were missed (i.e., false negatives). These calibration exercises have the potential to improve the predictability of the study and enhance the applicability of proximity loggers to key wildlife management issues such as disease transmission rates or wildlife use of landscape features and resources.
Original languageEnglish
Pages (from-to)1-15
Number of pages15
JournalThe Journal of Wildlife Management
Publication statusPublished - 28 Dec 2021

Bibliographical note

Funding Information:
We acknowledge the work of S. Nicoloso and M. Corrà in manufacturing WildScope. We thank C. Pucci and the staff of Stelvio National Park who allowed us to test collars on their animals. The research was conducted with the support of the Forestry and Wildlife Service of the Autonomous Province of Trento. This project was partly funded by Autonomous Province of Trento (PAT), under grant BEARNET, protocol N. S044‐5/2012/226570. F. Ossi was granted 3 yearly scholarships financed by the European Union (European Social Funds), Aosta Valley Autonomous Region, and the Italian Ministry for Work and Social Politics.

Publisher Copyright:
© 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society


  • Ecology
  • Ecology, Evolution, Behavior and Systematics
  • General Earth and Planetary Sciences
  • General Environmental Science
  • Nature and Landscape Conservation


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