Tree Swallow (Tachycineta bicolor)
Tree Swallow Missouri Department of Conservation
Barn Swallow (Hirundo rustica) - Mississippi National River & Recreation Area (U.S. National Park Service)
Tree Swallow State of Tennessee, Wildlife Resources Agency
Ohio Birds and Biodiversity: Tree Swallows, chilled
Tree Swallow Audubon Field Guide
Tree Swallow - eBird
Tree Swallow - eBird
Violet-green swallow - Wikipedia