The 2,200-acre estate that is the southwestern corner of Cape Elizabeth is home not only to members of the Sprague family but also a vast array of plants and animals in a secluded environment.

Each year, Maine Audubon takes a small group on a guided tour of the estate as part of the organization’s summer programs. Otherwise, the land is closed to the public.

The tour is led by John Greene, who has managed the property for the Sprague Corporation for 23 years, as well as Audubon bird and plant experts.

The property is home to species rare in Maine, and even in the U.S., including natural American chestnut trees, pepperbush, Indian pipe – a flowering plant that has no chlorophyll – and birds not commonly seen, either, like the Cooper’s hawk.

It is also home to a herd of deer that needs annual culling lest the woodlands’ understory be completely eaten. (The hunt is a bowhunt, and all the meat is donated to local food pantries.)

It is peaceful walking along the dirt roads, former farm tracks now used either as driveways to houses in corners of the property or as paths for family members to walk, mountain bike or ride horses along. Cedar waxwings and thrushes call throughout the property, much of which is managed under a forestry plan for sustainability.

The paths are lined with a combination of native plants – like St. John’s wort, Queen Anne’s lace and wild asparagus; invasives – such as bittersweet and honeysuckle (which sometimes appear to be attacking each other); and imported ornamentals, like the colossal rhododendrons and azaleas that have grown unchecked since they were first planted to decorate the carriage tracks.

In various places, high- and low-bush blueberries, blackberries, raspberries and even cranberries thrive, providing snacks for walkers and food for the birds.

At times, artifacts of the estate’s history appear. Two lifeboats – one wooden and one steel – rest in the grasses far from shore, recalling the days nearly 100 years ago when coal magnate Phineas W. Sprague bought up a number of farms over several years, granting the farmers life tenancy and folding their lands into the larger estate as they died. The boats wait where many of their ilk were stored, awaiting service on the 80 ships of Sprague’s fleet.

Along many paths are 10 to 15 miles of old wire fencing throughout the property, a testament to the land’s former use as a red deer farm. A root cellar is almost completely swallowed by plant life, but is still used for storage of various items. More visible is a stone potting shed in the middle of a field near what used to be an expansive garden and greenhouse structure, right next to a tennis court.

Among the ponds, some of which were made for irrigation on the old farms, are fields that have been recovering for 80 years or more. Around one corner, an old sand dune system rises amid woodlands, far inland from where the shore is today.

A path leads from the woodlands over a freshwater marsh – on modular docking chosen because of its simplicity of installation and minimal impact on the wetlands – toward the beach, where some of the sand is stained purple by fractured garnet underground. Out on the sand are semipalmated sandpipers, the occasional plover and any number of gulls, as well as views out into the Atlantic Ocean.

At times, you can hear no human sound, with wind blowing through the spruces and pines, calls of friendly nuthatches and chickadees coming down from the branches to check out the passersby.

On last weekend’s walk, a flight of seven great blue herons passed far overhead, their bent necks and oscillating flight pattern giving away their species even from hundreds of feet below.

The estate is actively involved in conservation, not just of its own ambience, but also of the wider community. People working on developing a new American chestnut come from time to time to take cuttings from the natural trees on the Sprague land, hoping to breed resistance to the blight fungus that killed off nearly all of the species, hardwoods that helped make the American forests great.

Birdwatchers scan the skies on the Sprague property during a Maine Audubon tour.