Estimating the population size of animals is an important task for wildlife biologists, who can use the data to assess the health of a population. It requires diligent observation skills coupled with the ability to use empirical models that effectively determine the number of animals based on field surveys. The most common method for estimating the population size of animals is mark and recapture. This method requires capturing and marking individuals, followed by subsequent capture sessions. The number of individuals marked and unmarked in subsequent capture sessions are used to determine the population size. This case study introduces two empirical models for mark and recapture and applies one of the models in an application activity investigating the expansion of coyotes in urban areas.