As winter closes in across much of North America, migratory birds are heading south to warmer climes and more abundant food. But until recently, scientists didn’t have a good understanding of exactly where they went. Researchers from the Wildlife Conservation Society (WCS) and the Cornell Lab of Ornithology U.S. analyzed observations from eBird, a global citizen-science database of sightings submitted by bird-watchers. They found that in 2022 more than half of the 314 migratory bird species they studied went to the five great forests of Central America. They write that 5 billion migratory birds funnel through Central America each year. Many stop in the rainforests, alpine wetlands and mangroves of the five great forests: Selva Maya in Mexico, Belize and Guatemala; Moskitia in Honduras and Nicaragua; Indio Maíz-Tortuguero in Nicaragua and Costa Rica; La Amistad in Costa Rica and Panama; and the Darién in Panama and northern Colombia. Collectively, these forests cover more than 10 million hectares (2.5 million acres), the researchers write. The five great forests. Image courtesy of Trillion Trees. The study found that many species spend the entire winter in these forests, including one in four wood thrushes (Hylocichla mustelina). Others, including one-third of broad-winged hawks (Buteo platypterus) and 40% of cerulean warblers (Setophaga cerulea) use the forests as a stopover for journeys farther south. Cerulean warbler populations have declined by roughly 70% since the 1970s. “The density of migratory warblers, flycatchers, and vireos crowded into these five forests is astounding, and means that each hectare protected…This article was originally published on Mongabay