Spix's macaws (L-R) Felicitas, Frieda, Paula and Paul sit on a branch in their aviary in Germany. The species has not been seen in the wild for 15 years until the recent sighting in Brazil.
There are about 400,000 greater sage grouse left on the landscape, spread across 11 Western states, from California to North Dakota. That's a fraction of what their numbers were just a century ago.
Tom Koerner/U.S. Fish and Wildlife Service
One of these things is not like the other: A 3-D printed model of a beige cowbird egg stands out from its robin's egg nest mates, though their shape and heft are similar.
Ana Lopez/Courtesy of Mark Hauber