Welcome to the hummingbird master class on nest concealment and feeding basics. These 2-inch-wide rufous hummingbird nests are built with moss, or other soft plant material, held together with spider web and camouflaged with lichen. And the lucky chicks, likely two, get a regurgitated feeding of nectar with a side of insects mom caught in midair. This amazing scene was captured recently at Billy Frank Jr. Nisqually National Wildlife Refuge in western Washington state. USFWS video: A. Froschauer

Help scientists understand how Rufous Hummingbirds are affected by climate change by participating in Hummingbirds at Home, an Audubon program made possible with support from GEICO. | National Audubon Society

Discover the powerful effect hummingbirds have over their wild neighbors in Costa Rica. "The Hummingbird Effect" premieres Wednesday, April 12 at 8/7c on PBS. [VID: In Costa Rica, much of life depends on a tiny little bird. An architect who brings flowers to the fields and fruit to the forest. The result is a realm bursting with wildlife. This is The Hummingbird Effect.] | Nature | PBS