Field Sparrow Bonaparte's Gull Warbling Vireo Tallgrass Prairie National Preserve Eastern Meadowlark Tallgrass Prairie National Preserve Bison Bison Valley Forge National Historical Park Fade to Purple Underground Visitor Center Juvenile Northern Mockingbird Winter Huts at ValleyForge Bunks in the winter cabins Cannon at Valley Forge Valley Forge Station George Washington Washington's Headquarters Washington's Headquarters Mexican Mallard x Northern Mallard Hybrid Bosque del Apache National Wildlife Refuge Sandhill Crane Ross's Goose Fish Crow Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Steamtown National Historic Site Elisha_A_Hancock_005 Common Nighthawk (Chordeiles minor) Common Nighthawk (Chordeiles minor) Grack on a Hot Wooden Perch Heat Wave Plains Pocket Gopher (Geomys bursarius) in memoriam Not one our nation's finest hours. Sand Creek Massacre National Historic Site Twelve-Spotted Skimmer (Libellula pulchella)