Common goldeneye duck eggs rest in a nest box placed on a tree by the U.S. Fish and Wildlife Service at the Chena River Lakes Flood Control Project in North Pole, Alaska. Working with park rangers at the U.S. Army Corps of Engineers – Alaska District, field researchers track the birds’ use of the boxes to study duck nesting ecology. The data is analyzed by scientists to better understand environmental impacts on the species in its northern-most breeding habitat. (U.S. Army photo)