  Encounter rates link movement strategies to intra- and inter-specific
interactions, and therefore translate individual movement behavior into
higher-level ecological processes. Indeed, a large body of interacting
population theory rests on the law of mass action, which can be derived from
assumptions of Brownian motion in an enclosed container with exclusively local
perception. These assumptions imply completely uniform space use, individual
home ranges equivalent to the population range, and encounter dependent on
movement paths actually crossing. Mounting empirical evidence, however,
suggests that animals use space non-uniformly, occupy home ranges substantially
smaller than the population range, and are often capable of nonlocal
perception. Here, we explore how these empirically supported behaviors change
pairwise encounter rates. Specifically, we derive novel analytical expressions
for encounter rates under Ornstein-Uhlenbeck motion, which features non-uniform
space use and allows individual home ranges to differ from the population
range. We compare OU-based encounter predictions to those of Reflected Brownian
Motion, from which the law of mass action can be derived. For both models, we
further explore how the interplay between the scale of perception and home
range size affects encounter rates. We find that neglecting realistic movement
and perceptual behaviors can systematically bias encounter rate predictions.
