There is mounting concern about declines in wildlife populations in many protected areas in Africa. Migratory ungulates are especially vulnerable to impacts of changing land use outside protected areas on their abundance. Range compression may compromise the capacity of migrants to cope with climatic variation, and accentuate both competitive interactions and predation. We analyzed the population dynamics of 11 ungulate species within Kenya’s Nairobi National Park, and compared them to those in the adjoining Athi-Kaputiei Plains, where human settlements and