Anthropogenic nest material incorporation and associated lethal entanglement in the Little Swift Apus affinis at a park entrance gate in Masai Mara, Kenya

Abstract

The incorporation of anthropogenic nest materials into avian nests is a growing global threat, yet macro-ecological records remain heavily skewed toward the Western Palearctic. When string-like synthetic debris are woven into nests, they create a persistent physical hazard that can entangle and kill both adults and nestlings. I document the first confirmed case of plastic nest incorporation and associated lethal entanglement for the Little Swift Apus affinis, recorded on 17 August 2025 at Talek Gate, Masai Mara National Reserve, Kenya. Multiple colonial saliva-bound nests structurally incorporated artificial debris, consisting of green, transparent, and white linear plastic filaments, alongside blue and white films. An adult Little Swift carcass was found suspended by its neck from a fine, transparent synthetic filament tightly woven into the entrance rim of a nest cup. This mortality event highlights the risk that uncontained municipal waste streams pose to synanthropic aerial insectivores breeding on human-made structures.