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Fig. 1 | Movement Ecology

Fig. 1

From: Quantifying animal movement for caching foragers: the path identification index (PII) and cougars, Puma concolor

Fig. 1

Summary of derived metrics used in wildlife GPS telemetry and simulated movement studies. Common movement metrics derived from point observations along an animal’s path include step-length, the Euclidean distance between consecutive points in time, which is easily converted to speed by dividing the net displacement distance by the associated time interval. Turn-angle is another common measure in the movement ecology literature. Less frequently used measures include path tortuosity or straightness that compares the net displacement over a series of observations (the chord) to the length of the path. Residency times or re-visitation rates are commonly estimated using a radius around an observation to measure the number of observations within a given distance for a given time interval. a. An illustrated movement type that has been the focus of movement ecology literature, a correlated random walk in response to a landscape covariate. Slow speed combined with high degrees of turning (search behavior shown in orange) in high quality habitat (green background) compared to fast directed movements in low resource availability (tan background) areas have dominated the literature. b. Illustrated movement path of caching or hoarding foraging movements where feeding is interrupted by short periods of other activities, such as resting away from the cache. The illustration shows speed and turn-angle are not always associated with foraging, but site recursion and how observations are related to one another in space and time show a movement pattern. Open circles represent failed fix attempts and offset location positions are used to illustrate the imperfect detection of GPS telemetry

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