In the Scarborough Marsh on April 25, Julia Mast holds an antenna as she listens for blips indicating a radio-collared cottontail rabbit is nearby. Mast, a senior studying environmental science at the University of New England, is an intern with the Maine Department of Inland Fisheries and Wildlife, which recently released eight cottontail rabbits to the marsh. Gregory Rec/Staff Photographer

SCARBOROUGH — Julia Mast walks deliberately along a grassy trail near the Scarborough Marsh, pointing a radio telemetry antenna at the thick tangle of shrubs on either side.

At the edge of an overgrown field, she stops to adjust dials on the tracking unit’s receiver and hears the soft pulsing beep she’s been waiting for. Somewhere nearby, hidden deep in thickets away from predators, are eight endangered New England cottontail rabbits. Mast, a University of New England student intern who tracks the bunnies twice a week, has never seen one.

The rabbits, outfitted with small radio-transmitter collars, were released in this wildlife management area off Manson Libby Road in late March as part of a project to restore the New England cottontail population in Maine. Despite constant threats from predators, all eight are still alive and may have produced their first offspring by now.

“It’s tremendously successful to have them all alive a month in,” said Cory Stearns, a small-mammal biologist and cottontail specialist for the Maine Department of Inland Fisheries and Wildlife.

There are only about 300 New England cottontails in Maine, but restoration efforts in the southern coastal towns where they live have started to increase the population and genetic diversity. The small brown rabbits, known for being elusive and ill suited to Maine winters, are found only in Cape Elizabeth, Scarborough, Wells, Kittery, Eliot and the Berwicks.

Cape Elizabeth is the stronghold for cottontails in Maine, with about two-thirds of the state’s population. Down in Wells, cottontails released at the Wells Reserve at Laudholm are doing so well they’re starting to venture beyond the reserve.

New England cottontails and snowshoe hare are the only rabbits native to Maine. For centuries, the cottontails were a vital part of Maine’s ecosystem, dispersing seeds and providing food for prey species such as bobcats, coyotes and hawks.

When farms were abandoned in the late 1800s and early 1900s, fields grew into shrubland and young forest, creating the perfect habitat for cottontails to thrive. The population peaked in the 1960s as rabbits spread as far as Oxford County, Auburn and Belfast, Stearns said.

There are about 300 New England cottontail rabbits in Maine. U.S. Fish and Wildlife Service

Over time, the young forest matured, shading out the smaller trees and shrubs that made  up the thickets that provided cottontails protection from hawks, owls, foxes and other predators. More habitat was lost to development, of course. Fewer timber harvests, wildfires and floods, meanwhile, kept young forest from being created.

In the 1980s, an estimated 85 percent of potential cottontail habitat was in young forest stage, Stearns said. Now it’s 3 percent or less.

“With that drastic drop in habitat, naturally the rabbits are going to decline as well,” he said. “There are fewer and fewer places for rabbits to hide.”

New England cottontail, added to Maine’s endangered list in 2007, is the state’s most imperiled species of those that depend on shrubland and young forest to survive. The population has struggled across the rest of New England, though the release of cottontails bred in captivity has led to a resurgence on Patience Island in Rhode Island.

“We are hopeful in Maine right now,” said Sarah Dudek, the New England Cottontail Restoration coordinator for Maine. “There is an upward trajectory of the population, which is great news.”

RESTORING THE RABBIT POPULATION

After the New England cottontail was placed on Maine’s endangered species list, the state, the USDA Natural Resources Conservation Service, Rachel Carson National Wildlife Refuge and conservation organizations came together to work on the rabbits’ recovery. Their plan focused on restoring large patches of habitat near existing populations.

“As a state, there’s an obligation to support the endangered species with Maine and help them as best we can,” Dudek said.

New England cottontails can be seen as an umbrella species, or a species selected as representatives of their ecosystem when conservation plans are made. Avian species, reptiles and amphibians benefit from the preservation of cottontail habitat, Dudek said.

The first habitat restoration projects started more than a decade ago at the Wells Reserve, Ram Island Farm in Cape Elizabeth, Rachel Carson National Wildlife Refuge and York Land Trust’s Highland Farm Preserve. Conservationists harvested trees and cut down nonproductive shrub areas. They planted seedlings of native trees and shrubs and controlled invasive plants to create dense thicket habitats.

Wells Reserve, a national estuarine research reserve, at one time was a local cottontail refuge, but the population declined until few or none remained on the conserved land. Using a 15-year grant from the NRCS, staff at the reserve identified areas where they could manage the habitat that cottontails thrive in, said Jacob Aman, the reserve’s stewardship director.

After 12 years of habitat work – including removing perches hawks use to spy little rabbits hopping around – it was finally time to bring rabbits in.

In the fall of 2017, 21 rabbits that had been raised in captivity were released at the reserve. A survey the following February found signs that seven were still there. More successful releases followed in 2018 and 2019. Four rabbits released at the reserve last fall came from the Queens Zoo in New York and the Roger Williams Park Zoo in Rhode Island.

More than 60 rabbits have now been released at Wells Reserve and it appears many are surviving and breeding. Most of the 25 rabbits identified through surveys last year were wild-born. The cottontails have started to spread out from the areas where they were released.

“It’s now one of the best populations we have in the state,” Stearns said.

On a cold, sunny day in January, volunteers and employees of the Cape Elizabeth Land Trust met at Runaway Farm to begin the tedious task of removing dense tangles of invasive honeysuckle and bittersweet. The trimmings went into brush piles that New England cottontails can use to hide from predators.

The effort to create better cottontail habitat at the 50-acre preserve on Spurwink Avenue began after bunnies were spotted on the property. The land trust secured $16,500 in outside funding to carry out the restoration plan on 7 acres.

The land trust hopes this work will allow the farm’s New England cottontail population, now believed to be around a dozen, to flourish, said Ardath Dixon, the land trust’s stewardship manager.

Dudek, the New England Cottontail Restoration coordinator, is making a push this year to recruit landowners in the half-dozen areas with New England cottontails to preserve more habitat for the rabbits. She’s looking for land near conservation areas that would allow the existing cottontail population to spread out without being too threatened.

Dudek works with landowners to secure NRCS funding to pay for habitat restoration work on their land. She helps develop a plan for each property and follows up to assess if cottontails have found and are using the habitat.

The work done on these properties varies, Dudek said, but is all focused on creating the dense, shrubby understory where rabbits can hide from predators. In fields, she may suggest planting native shrubs. If an area is already thick with shrubs, the push might be to manage invasive species. In forested areas, large canopy trees are taken out to promote understory growth.

Meanwhile, the state continues to do surveys to assess the size and spread of the cottontail population. Every winter, biologists collect pellets that are then sent to a lab for DNA analysis. That testing determines if the rabbits were released or born in the wild.

Biologists from the Maine Department of Inland Fisheries and Wildlife also follow up on rabbit sightings reported through their agency’s website to look for signs that New England cottontails are moving into new areas. Most of the sightings turn out to be snowshoe hares or Eastern cottontails, a non-native species that has been moving into Maine and pushing out New England cottontails.

“We are hopeful in Maine right now. There is an upward trajectory of the population, which is great news,” Dudek said. “I hope the releases will continue to increase the population and genetic diversity and keep these rabbits out of such dire straits.”

HOPE IN THE SCARBOROUGH MARSH

Twelve years ago, a few New England cottontails were confirmed at Scarborough Marsh, in a quiet area off Manson Libby Road. There was very little suitable habitat, and that was the last time cottontails were documented in the area.

But there was a lot of potential to create habitat at the 65-acre wildlife management area.

Cory Stearns, a small-mammal biologist with the Maine Department of Inland Fisheries and Wildlife, walks along a trail in the Scarborough Marsh with intern Julia Mast on April 25 as the two track cottontail rabbits that are wearing radio collars. Gregory Rec/Staff Photographer

Stearns, the cottontail specialist, said a timber harvest in 2011 removed large trees from a pine-dominated older forest to allow new shrubs and trees to grow. Thousands of shrubs – dogwoods, willows, hazelnut, Virginia rose and others – were planted in fields to offer cover for cottontails. That work is ongoing.

But finally, after years of preparation, enough habitat was ready to safely release rabbits.

Three New England cottontails arrived in Maine on March 3 from Rhode Island, where they were trapped from the successful breeding colony on Patience Island. Maine’s Department of Inland Fisheries and Wildlife trapped five additional rabbits in Cape Elizabeth.

The rabbits stayed together at the Maine Wildlife Park in Gray until grass and leaves provided enough cover in their new Scarborough habitat. Six rabbits were released in pairs on March 22; the other two were released a week later.

Mast, the UNE intern, visits every Monday and Friday to track the rabbits using radio frequencies. Slow beeps on the telemetry receiver indicate a rabbit is within a half-mile. If a rabbit hasn’t moved in eight hours, the beeps are faster and indicate it likely has not survived.

Over the past month, Mast has learned the areas where the rabbits tend to linger. Most stay relatively close to the area where they were released, but one wanders a bit farther afield and can be tricky to find. While she’s at the marsh, Mast often sees signs of the predators that pose a threat.

“There have been a lot of hawks around and they make me nervous,” Mast said.

Stearns joined Mast last week to track the rabbits and will return again soon to install game cameras with hopes of catching a glimpse of the cottontails and their babies. As Mast tuned the receiver to try to find that one wandering rabbit, Stearns described how cottontails being released will sometimes linger in their carriers or on trails, unsure of what to make of their new surroundings.

But here on the edge of the Scarborough Marsh, the cottontails hopped away immediately, bound for their new life in the thicket.