Mexican Mallard x Northern Mallard Hybrid Bosque del Apache National Wildlife Refuge Sandhill Crane Ross's Goose Gambel's Quail Harris's Sparrow Eastern Phoebe A Mountain of Sandhills Bewick's Wren Phainopepla Canyon Towhee Bushtit Mexican Mallard Curve-Billed Thrasher Black-Throated Sparrow Vermillion Flycatcher Anna's Hummingbird Ladder-Backed Woodpecker Gila Woodpecker Gila Woodpecker Gila Woodpecker Yellow-Rumped Warbler Female Great-Tailed Grackle Washington's Headquarters George Washington Valley Forge Station Cannon at Valley Forge Bunks in the winter cabins Winter Huts at ValleyForge Juvenile Northern Mockingbird Underground Visitor Center Fade to Purple Valley Forge National Historical Park Bison Bison Tallgrass Prairie National Preserve Eastern Meadowlark Tallgrass Prairie National Preserve Warbling Vireo Bonaparte's Gull Field Sparrow Indigo Bunting Fish Crow Steamtown National Historic Site Steamtown National Historic Site