Bird-window collisions in Costa Rica: taxonomic characterization, migratory status, geographic distribution and conservation

Bird-window collisions cause the death of billions of birds worldwide, yet few studies exist on this problem in Tropical America. This study, based on the collaborative work of hundreds of volunteers from 2013 to 2024, documents in detail the bird species that collide with windows in Costa Rica in order to establish fundamental baseline information for future research and to recommend conservation actions. A total of 1,506 bird collision reports were documented from the country’s seven provinces. A total of 296 species from 47 families and 17 orders were counted. The most frequently reported species was Catharus ustulatus (Swainson’s thrush) (n = 142), and the three most frequently reported families were Turdidae, Trochilidae, and Parulidae. Eighty percent of the recorded species were resident (250, n = 1006), compared to latitudinal migrants (59, n = 466). Resident species were present in greater numbers in the non-urban areas of Monteverde, Sarapiquí, San Gerardo de Dota, and San Vito de Coto Brus than in the urban area of San José. Bird-window collisions affect a high number of bird species in Costa Rica, including endemic and endangered species. We recommend using proven effective methods to prevent collisions and the development of legislation and building regulations to protect wild birds.