Breeding in the cold? A White-eared Hummingbird (Basilinna leucotis) winter nest record from the mountains of Southern Oaxaca, Mexico

We report the finding of a White-eared Hummingbird (Basilinna leucotis) nest during the winter. The observation took place on 9 February 2019 in San José del Pacífico, Oaxaca, Mexico, in the Sierra Madre del Sur. The hummingbird nest was located in the understory, 115 cm above the ground. The nest was placed within a plot of a pine-oak forest at 2,857 m a.s.l. and had 2 nestlings with complete juvenile plumage. Floral phenology is known to be a key factor that determines the biological cycles of hummingbirds, which rely heavily on nectar resources to fulfill their nutritional needs in the breeding season. Around the nest, we observed Salvia punicans Epling, a plant that blossoms during the winter months in the Mexican mountains and is visited by White-eared Hummingbirds. Previous winter nest records in Southern Oaxaca date from more than 50 years ago. We briefly discuss the implications of winter reproduction for the species and the potential commonness of this event.