2015 CFHS National Animal Welfare Conference
Identifying the important factors contributing to the domestic cat (Felis catus)
overpopulation issue in Guelph, Ontario
Tyler Flockhart, PhD and Jason Coe, DVM PhD, Department of Population Medicine,
Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
Responsible solutions to address the cat overpopulation crisis require measuring changes in
population size over time and knowing the factors that drive these changes. However, to address
homelessness, over-taxed animal shelters and unnecessary euthanasia, we must consider owned
cats, free-roaming cats and cats in the shelter system simultaneously. The reason is that human
interventions can move cats between these categories (e.g. adoption, abandonment) and change
the future number of cats in each category (e.g. through sterilization). In this presentation we
highlight the results of the first inclusive model to consider all these populations concurrently,
how they interact, and the factors that drive changes in population size that can be applied to any
city in North America. To validate the generality of our model, we compare the predicted feral
cat population size derived from the population model to published estimates of feral cat
population size in major cities in Canada as well as the predicted proportion of previously
sterilized feral cats that are captured during trap-neuter-return programs from cities in the United
States. We then walk through a case-study by applying detailed shelter-specific income-outcome
information and data from free-roaming cat population counts for the city of Guelph, Ontario
(population 120,000). Finally, we discuss how the portion of the population and the specific
factors that have the greatest impact on reducing cat population size depend on which population
(owned, free-roaming and shelter) is of interest to stakeholders. Ultimately, ensuring that
evidence-based population models accurately reflect the complexities of the cat overpopulation
problem will require data and buy-in from all stakeholders. Quantitative models, such as the one
we highlight, are a necessary first step to designing robust and cost-effective strategies that have
the greatest potential to reach our collective cat population management goals.
Key Learnings:
1. How population models can be used to manage cat overpopulation.
2. The pros and cons of general population models vs population models for a specific
location.
3. Factors identified to be influencing cat overpopulation in Guelph, Ontario (120,000
people).
Speaker Biographies:
Dr. Tyler Flockhart is a population ecologist and conservation biologist interested in
understanding the factors that influence changes in animal populations and applying decisiontheory to design optimal management strategies for species of concern in the face of global
change. He recently developed a year-round population model of migratory monarch butterflies
that is helping guide conservation planning across Canada, the United States and Mexico.
Currently, he is working on developing evidence-based population models to make optimal
decisions to address cat overpopulation.
Dr. Jason Coe studies the human-animal bond and the role of interpersonal communication in the
outcomes of veterinary care, the causes of animal relinquishment and issues surrounding animal
overpopulation. Dr. Coe completed a Doctor of Veterinary Medicine in 2001 and a PhD in
Epidemiology in 2008 at the University of Guelph. He holds the Nestlé Purina PetCare Canada
Chair in Communications and is an Associate Professor in the Department of Population
Medicine at the University of Guelph.