There are eight species of swallows in North America with seven species in Montana. The cave swallow is mostly found in Texas and Mexico. Tree, violet-green, northern rough-winged, bank, barn, ...

Courtesy of Houghton Mifflin Co. During April, six species of swallows migrate in from the South. The first one to appear is the tree swallow and it nests in a natural cavity or in a nest box and ...

Tree anatomy, including leaf shape and twig parts, helps you identify and name tree species. Knowing a tree's physiology will help with identification.

Leaf Anatomy. Steve Nix Botanical Structures on a Leaf . A tree's leaf is the best major botanical marker that helps in keying out and identifying any species of tree that has a leaf.

image: The Tree Swallow population on Canada's Kent Island has collapsed as immigration from the mainland has declined. view more . Credit: B. Woodworth.

Tree swallow nests across Pennsylvania are being collected for an investigation into the patterns that the common, fast-flying, cavity-nesting birds might incorporate into their nest construction ...

It’s Feb. 20 and the first spring migrant is flying low over the waters of a mountain lake in Transylvania County. The first tree swallow has arrived, but winter has not yet retreated and it’s a ...