Massachusetts Plans Quabbin Reservoir Timber Rattlesnake Colony

Summary: Massachusetts plans Quabbin Reservoir timber rattlesnake colony on uninhabited Mount Zion as refuge for the seriously endangered venomous pit viper.

Quabbin Reservoir, with South Baffle Dam connecting Walker Hill Island's south end to mainland (foreground) and North Baffle Dam connecting Walker Hill's north end to south end of Mount Zion (upper center): Clif Read, Director, DCR Quabbin Visitors Center, via Massachusetts Department of Conservation and Recreation

MassWildlife is holding an informational meeting Tuesday, Feb. 23, 2016, in Orange concerning Massachusetts’ plans for a Quabbin Reservoir timber rattlesnake colony on uninhabited Mount Zion, Quabbin’s largest island, as a high conservation priority for the commonwealth’s seriously endangered venomous pit viper.

Tom French, assistant director of MassWildlife’s Natural Heritage and Endangered Species Program, explains the rationale for setting up a Quabbin Reservoir timber rattlesnake colony in a video published Monday, Feb. 1, 2016, on YouTube by MassWildlife: “Our proposal to release rattlesnakes on an island in the Quabbin has evolved out of really the necessity of having at least one place in this state that’s a safety net for rattlesnakes, a place that they can be that they can be safe from people. Not the other way around. People are doing just fine. But the snakes need a place that they can avoid people and the road mortality and the deliberate killing that’s come from the public in the past.”

Mount Zion, the proposed locale for the Quabbin Reservoir timber rattlesnake colony, covers an area of approximately 1,350 acres, with a length of 3.64 miles (5.85 kilometers). The island’s size compares favorably with current, timber rattlesnake-occupied habitats elsewhere in Massachusetts. Mount Zion is excluded from public access.

Mount Zion’s attractions for the proposed Quabbin Reservoir timber rattlesnake colony include an excellently varied forest dominated by hardwoods and geologic features allowing access to timber rattlesnakes’ trademark of unusually deep hibernation sites, known as hibernacula. Timber rattlesnakes’ most common prey, the eastern chipmunk (Tamias striatus) and the white-footed mouse (Peromyscus leucopus), are found on Mount Zion.

Mount Zion is one of 66 islands greening the reservoir’s 25,000-acre surface area. A one-lane, 0.3 mile- (0.48 kilometer-) long causeway connects Mount Zion’s south end to 40-acre Walker Hill island's north end. Another causeway links Walker Hill's southern end to the surrounding mainland in Worcester County.

The causeways are actually baffle dams that increase the reservoir's water retention by five years. The dams redirect water flowing into Quabbin Reservoir from the Swift River East Branch and from the Ware River to a counter-clockwise, northward direction around Mount Zion. The flows' increased residence time in the reservoir encourages greater natural purification as well as improves water quality.

North Baffle Dam serves as dirt-and-stone causeway connecting Mount Zion island with Walker Hill Island; South Baffle Dam connects Walker Hill to the reservoir's east central shore, to the west of the town of Hardwick: Clif Read/Massachusetts Department of Conservation and Recreation, September 2013 handout photo via Phys.org

Timber rattlesnakes are good swimmers, when necessary, but, as denizens of their dens, they rarely journey more than 2 to 4 miles (3.2 to 6.4 kilometers) away from their den sites. Dispersal from Mount Zion to the mainland via reservoir swims is considered fatally unlikely.

“Could they leave the island? They’re perfectly good swimmers,” explains French. “But if a snake were to swim off the island, it would be unable to track itself back to the hibernation site. It’s too far to find another site like that, so it wouldn’t make the winter. It would die over the winter.”

The last known human fatality in Massachusetts from a timber rattlesnake bite happened in 1791.

Historically widespread throughout Massachusetts, the native commonwealth-listed endangered species now survives in only five scattered populations that range from the Blue Hills Reservation near Boston westward to the Connecticut River valley and farther west to the New York border in the southern Berkshires. The population currently is estimated at less than 200 individuals. Most of the populations are found in heavily visited state parks, forests and MassWildlife lands where high road-killed death rates result from the rattlers’ preferences for basking along roads and trails as well as for crossing over roads rather than using small culverts.

In addition to road killing, modern-day factors that imperil timber rattlesnakes include destruction of rocky and woodland habitats, excessive collecting and fatal persecution by the general public and snake hunters. All of these factors occur illegally, in violation of the Massachusetts Endangered Species Act (MESA). Enacted in December 1990 and most recently revised as of Oct. 15, 2010, the Massachusetts Endangered Species Act prohibits listed-species taking, with illegal taking ranging from capture, collection, harassment and killing to habitat degradation, destruction or modification.

The Massachusetts Division of Fisheries and Wildlife, known popularly as MassWildlife, is responsible for conserving the commonwealth’s endangered and common fish and wildlife species. MassWildlife’s Natural Heritage and Endangered Species Program (NHESP) protects native fauna and flora that are designated as endangered, of special concern or threatened.

MassWildlife’s timber rattlesnake public meeting is scheduled to begin at 7 p.m. Eastern Standard Time Feb. 23. The meeting will be held at the R.C. Mahar Regional High School, located at 507 South Main Street (Route 122), in the northwestern town of Orange.

A timber rattlesnake coils on a rock in western Massachusetts: Bill Byrne/Massachusetts Division of Fisheries and Wildlife, September 2008 handout photo via Phys. org

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Quabbin Reservoir: Clif Read, Director, DCR Quabbin Visitors Center, via Massachusetts Department of Conservation and Recreation @ http://www.mass.gov/eea/docs/dcr/watersupply/watershed/downstream30.pdf

causeway/baffle dam leading to Mount Zion: Clif Read/Massachusetts Department of Conservation and Recreation, September 2013 handout photo via Phys.org @ http://phys.org/news/2016-02-massachusetts-rattlesnake-colony-uninhabited-island.html

timber rattlesnake: Bill Byrne/Massachusetts Division of Fisheries and Wildlife, September 2008 handout photo via Phys.org @ http://phys.org/news/2016-02-massachusetts-rattlesnake-colony-uninhabited-island.html

For further information:

"Endangered Timber Rattlesnake Conservation Includes Introduction on Quabbin Island." Commonwealth of Massachusetts Executive Office of Energy and Environmental Affairs > Agencies > Department of Fish & Game > Fisheries & Wildlife > Natural Heritage & Endangered Species > Species Information & Conservation > Rare Reptiles & Amphibians.
Available @ http://www.mass.gov/eea/agencies/dfg/dfw/natural-heritage/species-information-and-conservation/rare-reptiles-and-amphibians/endangered-rattlesnake-conservation.html

Johnson, Patrick. "'Rattlesnake Island': Fisheries & Wildlife sees Quabbin as possible salvation of endangered timber rattlesnake; critics say plan makes their skin crawl." MassLive > News. Feb. 22, 2016.
Available @ http://www.masslive.com/news/index.ssf/2016/02/rattlesnake_island_fisheries_w.html

MA. Fish & Game @MassDFG. "Learn all about our conservation strategy for the timber rattlesnake in #MA with this great video from #MassWildlife." 8:55 a.m. Feb. 8, 2016. Tweet.
Available @ https://twitter.com/MassDFG/status/696739221734825984

MassWildlife. "MassWildlife / Plan to Establish Rattlesnakes at Quabbin." YouTube. Feb. 1, 2016.
Available @ https://www.youtube.com/watch?v=JZEzRBdYg1U

Pratt, Mark. "Massachusetts plans rattlesnake colony on uninhabited island." Phys.org > Biology > Plants & Animals. Feb. 21, 2016.
Available @ http://phys.org/news/2016-02-massachusetts-rattlesnake-colony-uninhabited-island.html

Read, Clif. "Quabbin Islands: The High Grounds of the Swift River Valley." Downstream newsletter, no. 30 (Fall 2013): 1, 4-5. Massachusetts Department of Conservation and Recreation.
Available @ http://www.mass.gov/eea/docs/dcr/watersupply/watershed/downstream30.pdf

"Timber Rattlesnake Crotalus horridus Fact Sheet." Commonwealth of Massachusetts > Energy and Environmental Affairs > Documents > Division of Fish & Game > Natural Heritage and Endangered Species Program. Updated 2015.
Available @ http://www.mass.gov/eea/docs/dfg/nhesp/species-and-conservation/nhfacts/crotalus-horridus.pdf