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).

Endangered Wildlife species:

The bald eagle (Haliaeetus leuococephalus) is our national bird, and a federally threatened species.  Learn more about this remarkable species, and HG&E’s restoration efforts on the Connecticut River.


A mature bald eagle is easily identifiable by its blackish-brown body and characteristic white head.  Juvenile eagles are typically light brown, and take about 5 years to develop their adult plumage.  Adult female eagles have an average wingspan of 8 feet and a body length of 3 feet, with males being slightly smaller.  Bald eagles typically weight approximately 10-14 pounds and live an average of 15-25 years in the wild.  

A large portion of the Connecticut River Basin, including that which is in the area of the Holyoke Dam and Hydroelectric Facilities, provides good habitat for bald eagles which includes: the waterway with a plentiful source of food – fish;  as well as stands of forest for nesting, perching, and roosting for wintering eagles. 


Historically, Pioneer Valley resource decisions in the 1800’s set the area’s dependence on the Connecticut River for navigation, manufacturing and power, and accordingly resulted in changes to its flow, depth, floodplain, as well as loss of critical wildlife habitat, including that of the bald eagle.  By the late 1800’s, changes in land use and the westward expansion resulted in significant loss of bald eagle habitat and the decline of the population.  Eventually, the killing of bald eagles became prohibited under the Bald Eagle Act of 1940.  However, their continuing decline was the result of the concentration of organochlorines such as DDT within the food chain that caused the female to lay eggs with shells too thin to withstand incubation. 

Today, the bald eagle is beginning to reclaim some of its historic range.  In Massachusetts, this is primarily the result of the 1980’s Massachusetts Division of Fisheries & Wildlife hacking program.  Following the release of forty-one eagles from the Quabbin Reservoir, the bald eagle was confirmed as successfully breeding in the state in 1989.  In 1995, the bald eagle was down-listed from federally endangered to federally threatened.  It remains on the threatened and endangered species list in Massachusetts.

HG&E Restoration Efforts

During 2003, in consultation with the United States Fish & Wildlife Service as well as the Massachusetts Department of Environmental Protection, HG&E constructed three man-made eagles’ nests along the Connecticut River, between Hatfield and West Springfield.  For the next five years, HG&E monitored bald eagle use of these three sites, as well as a natural nest location that was being utilized by a mating pair of bald eagles.  Over this five year monitoring period, juvenile eagles were successfully fledged at two of the three man-made nests, as well as the natural nest.  By 2008, which marked the end of the monitoring period, a total of 16 eagles had successfully fledged from the monitored nests.  Although HG&E has since fulfilled its monitoring obligations, the man-made nests have been left at their respective locations.

The yellow lampmussel is an endangered species in Massachusetts, and is known to occur in only four rivers in New England; one of which is the Connecticut River.  It is a medium to large sized oval-shaped mussel that it typically less than 5 ¼ inches in length and is characterized by a bright shiny yellow shell that is apparent in young, healthy mussels, but may darken with age.  In its limited range in the Connecticut River, the yellow lampmussel has been found in areas ranging in depth from 3 – 30 feet, with low to moderate flows.

Working under its Threatened and Endangered Species Plan, and in consultation with various agencies and stakeholders, HG&E monitored yellow lampmussels within the area of the Holyoke Dam, starting 2003.  Monitoring efforts included an annual survey of yellow lampmussels in the Holyoke Canal System as well a survey of the Holyoke impoundment and bypass reach occurring every three years.  Note that the Holyoke impoundment includes the area of the Connecticut River bounded downstream by the Holyoke Dam and upstream by the Hatfield area, and the bypass reach is the area directly downstream of the Holyoke Dam. 

Did you know that, pound for pound, the adult Puritan tiger beetle is the fastest land animal on earth? Puritan tiger beetles are found in only two places in the world - the Chesapeake Bay and the Connecticut River – both in Massachusetts. State and federal endangered species laws protect the Puritan tiger beetle.

The Peregrine Falcon was once considered quite rare because of pesticide poisoning but has since made a comeback and sightings are increasing every year. 

The Peregrine Falcon is the fastest bird on earth, capable of diving from great heights at speeds of up to 200 miles per hour. It is a beautiful raptor with long, pointed wings and a long, slightly rounded tail. Adults have a bluish-gray to slate-gray backside and a buffy white underside interspersed with black. Adults also possess a black crown, black moustache-like markings or “sideburns”, a white throat, a dark bill with a prominent yellow fleshy base (or cere), and yellow legs and feet.

Peregrines prefer cliff nest sites  such as on Mount Tom. In general, Peregrine falcons prefer to nest on cliffs or man-made structures overlooking a body of water like the Connecticut River Valley.

Contact Info

99 Suffolk Street
Holyoke, MA 01040
Tel: (413) 536-9300
Toll-free: (877) 742-5443