Within Holyoke’s borders, approximately 242 species of vertebrates have been identified. These species include: 29 species of fish, including game fish such as Smallmouth and Largemouth Bass, Brook and Rainbow Trout, and Yellow Perch; 21 species of amphibians, including Spotted Salamanders and Wood Frogs of vernal pool fame; 18 species of reptiles, including all snake species found in the state; at least 160 species of birds, from Ruby-throated Hummingbirds to Bald Eagles; and about 42 species of mammals, from the common Gray Squirrels to an occasional wandering Moose.
The City’s Connecticut River frontage and undisturbed habitats on Mount Tom and East Mountain, give Holyoke more species of both plants and animals than most City residents (and nonresidents) realize. As a matter of fact, 47% of Holyoke's acreage is designated as Priority or Estimated rare species habitat by Natural Heritage and Endangered Species Program (NHESP).
A few endangered Wildlife species: