Chapter 7 - Estimating and Visualizing Movement Paths from Radio-Tracking Data

Abstract

Radio-tracking is a reasonable means to acquire movement data at many scales. It is the only practical means to gather movement path data on some vertebrates. Radio-tracking data, if gathered via triangulation or satellite tracking, can be imprecise and inaccurate relative to the scale at which one wishes to study movement phenomena. This chapter describes some of the sampling considerations and analytical tools helpful in acquiring and evaluating narrowly scaled movement data. The use of radio tracking to periodically locate an animal along its movement path renders continuous behavior into a set of discrete points. The frequency with which point locations are recorded (sampling frequency) relative to the speed of the animal directly influences the ability to reconstruct the actual path from these data. The imprecision inherent in radio tracking via triangulation or by satellite also contributes noise to movement path data. A radio-tracking system established to collect movement path data might consist of two or more receiving stations (towers) of known location from which azimuths to the target animal are measured periodically. A complicating factor in the use of radio tracking to describe animal movement paths is the white noise added to movement data by telemetry error.