Gardiner, Montana, to Mammoth Hot Springs, Wyoming Professional Review and Guide
"The birdlife of Yellowstone is highly underrated. Although bird concentrations are not extraordinary, the quality of birdlife is. General Information: A trip through Gardiner is not complete unless one drives through the stone archway known as the Roosevelt Memorial Arch. This unique basaltic structure was dedicated in 1903 by Teddy Roosevelt, commemorating the birth of the park.
But before traveling through the arch, take a rewarding side trip on the Stevens Creek Road. This route gives access to a less traveled part of the park, quality birding, and expansive vistas. This eTrail provides detailed information on birding strategies for this specific location, the specialty birds and other key birds you might see, directions to each birding spot, and helpful general information."