Domestic cats are the most popular pet in the United States. Many cats are kept outside or are released to roam free. These outdoor cats function as top predators and recent estimates suggest free-ranging cats kill >1 billion birds and 6.5 billion mammals annually. Some people have taken it upon themselves to care for these feral cats, feeding them and providing shelter. With new cats immigrating into these colonies, there is no accurate way to track the number of individuals and devise a plan to properly control populations. Our goal is to identify feral cat colonies and quantify the number of individuals moving into and out of the colony and track cat home-ranges. This information will help us understand the size of the colonies, the number of individuals moving into and out of the colony, and their impacts on the habitats these cats occupy.