Deer populations in suburban and urban areas are growing in many parts of the US and Europe. Their management raises complex welfare, safety, and ecological questions.
Urban deer welfare involves trade-offs between the welfare of individual deer and the welfare of other species affected by overabundant deer populations. Vehicle collision is the primary welfare harm for urban deer — collisions cause acute trauma and, for animals that survive the impact, prolonged suffering from injuries that may not be immediately fatal. Lyme disease tick burden is another deer welfare issue — heavy infestations cause chronic irritation and immune stress. From an ecological welfare perspective, overabundant deer create habitat conditions that reduce biodiversity and may harm the welfare of other species. Non-lethal management including immunocontraception is more welfare-compatible for individual deer but requires sustained investment and is most effective in isolated populations.