Cities are home to billions of wild animals sharing space with humans. Understanding how urban environments affect their wellbeing—and how to create more compassionate cities—is a growing frontier of welfare science.
Over the past century, as natural habitats have been lost to development, many wildlife species have adapted to urban environments. Cities are no longer wildlife deserts—they are increasingly complex ecosystems home to hundreds of species of birds, mammals, reptiles, and invertebrates.
This urbanization of wildlife creates profound welfare questions. Urban environments offer some advantages (supplemental food, reduced large predators, warmer microhabitats) but also severe challenges (vehicle collisions, pollution, light and noise disruption, disease, human conflict). Understanding these trade-offs is essential for building wildlife-friendly cities.
Welfare challenges: Mange (sarcoptic mite infestation) causes prolonged severe suffering; rodenticide secondary poisoning; road mortality; orphaned young from maternal trapping/killing.
Welfare opportunities: Raccoons adapt remarkably well to urban food availability; non-lethal exclusion methods protect both raccoons and homeowners; wildlife rehabilitators successfully treat mange with ivermectin.
Welfare challenges: Road mortality is a primary cause of death; mange; sarcoptic mange epidemics cause painful skin disease; rat poison secondary poisoning; harassment/persecution by homeowners.
Welfare opportunities: Fox populations self-regulate with food availability; healthy fox populations naturally suppress rat populations; mange treatment programs (medicated bait) show success in UK cities.
Welfare challenges: Lethal control (trapping, shooting) when livestock conflicts occur; mange; road mortality; pups orphaned when adults killed.
Welfare opportunities: Coyote coexistence programs (Chicago Urban Coyote Research Project) show lethal control is ineffective and unnecessary in most cases; hazing/deterrence works without killing.
Welfare challenges: Leg entanglement in debris and human hair; poisoning campaigns; "spike" infrastructure prevents roosting without addressing food sources; feral populations often have high disease burden.
Welfare opportunities: Oral contraception (OvoControl) reduces feral pigeon populations humanely over time; better waste management reduces attractants; pigeon towers provide humane alternative nesting sites.
Welfare challenges: Leg entanglement; poisoning; vehicle collisions; habitat loss reducing natural denning sites; domestic cat predation.
Welfare opportunities: Tree canopy connectivity reduces road crossing needs; wildlife-friendly property management; cat confinement policies protect squirrel populations.
Welfare challenges: Roost disturbance during maternity season causes mass pup mortality; exclusion when bats are present causes trapped-pup deaths; White-Nose Syndrome spreading through populations.
Welfare opportunities: Bat boxes provide alternative roost sites; seasonal exclusion timing (outside maternity season) prevents pup deaths; protected status in many jurisdictions.
Road mortality is the leading human-caused source of wildlife injury and death globally. Urban roads fragment habitat and create collision corridors. Animals struck by vehicles often die slowly from internal injuries. An estimated 1-2 million large animals and hundreds of millions of smaller animals are killed on US roads annually.
Free-ranging domestic and feral cats kill an estimated 1.3-4 billion birds and 6-22 billion small mammals annually in the US alone. Unlike natural predation, cat predation is additive to natural mortality in many populations, driving significant welfare impacts.
Birds cannot perceive glass as a barrier. An estimated 600 million to 1 billion birds die from window strikes annually in the US. Many more are injured and die slowly. Simple interventions—UV-reflective window films (invisible to humans, visible to birds), exterior screens, bird-friendly glass patterns—dramatically reduce strikes.
Artificial light at night disrupts circadian rhythms, navigation, foraging, and reproductive behavior across nearly all wildlife groups. Sea turtle hatchlings navigate toward city lights and away from the ocean; migratory birds are disoriented by lit buildings; firefly mating is suppressed; insects swarm and die around lights.
Second-generation anticoagulant rodenticides (brodifacoum, bromadiolone) bioaccumulate in predators. Hawks, owls, foxes, coyotes, and mountain lions are commonly found with rodenticide in their tissues. These poisons cause slow death from internal hemorrhage—significant welfare harms affecting both target and non-target species.
Wildlife corridors, urban trees, green roofs, pocket parks, and permeable surfaces create habitat connectivity. Cities like Singapore, Portland, and Amsterdam are global leaders in urban biodiversity integration.
Lights-out campaigns during migration season (Chicago, NYC's Project Safe Flight), warm-spectrum LED transitions, and shielded fixtures dramatically reduce light pollution impacts.
Indoor cat promotion, cat-free designated wildlife areas, and TNR programs in combination address both feral cat welfare and wildlife predation impacts.
Bird-friendly building codes (Toronto, San Francisco, New York) require window treatment on new construction. Retrofit programs provide incentives for existing buildings.
The world's largest wildlife crossing (Wallis Annenberg Wildlife Crossing over US-101, Los Angeles) opened in 2023—a landmark for urban wildlife connectivity. Many smaller crossings are being built globally.
IPM (Integrated Pest Management) approaches prioritize exclusion, habitat modification, and targeted interventions over broadcast rodenticide use—better for wildlife, raptors, and pets.
Wildlife rehabilitators provide critical welfare services to injured, orphaned, and sick urban wildlife—essentially a welfare safety net for animals in human-caused distress.