THE EARTH GIVES US SIGNS, if we know how to read them. Some scientists obsessively track environmental fluctuations like shifts in precipitation and insect populations in search of early warnings of climate change. But one co-inhabitant of Earth can teach us more about the climate than any other: birds. “Birds need what people need, such as clean water, healthy forests and resilient coastlines,” says David Yarnold, the president and C.E.O. of the National Audubon Society. As the canary in the coal mine metaphor suggests, when the birds are in trouble, so are we. Birds perform invaluable ecosystem services necessary for our survival, like pollinating plants and dispersing seeds to help countless species of plants survive. They also eat between 400 million and 500 million metric tons of insects a year globally, reducing the need for pesticides. Birds even perform the role of garbage disposal by devouring animal carcasses that would otherwise rot. As the effects of climate change become more pervasive, five North American species are particularly threatened. The Painted Redstart, Scarlet Tanager, Pygmy Nuthatch, Allen’s Hummingbird and Mountain Bluebird each help the environment in many ways, but their habitats are at risk, unless we start revitalization efforts soon. From the soft buzzing of the hummingbird’s wings to the sweet whistle of a warbler, birds are constantly communicating. Through their actions and very existence, they’re also sending us a message. It’s time to listen. Learn about these beautiful, essential creatures and the incredible impact they have on the planet, below.