The human history of Acadia National Park is usually thought of as beginning in the early 20th century, when preservationists banded together with wealthy philanthropists to set aside and create the park we know today. In fact, its clock winds much farther back than that—beginning thousands of years ago, when local Native American tribes fished its shores and hunted its hills. But even that is just a flake off the deep, deep time that has been required to create Acadia. The rocks upon which you climb, sun yourself, and picnic are old—staggeringly old.

Before arriving, then, one would do well to acquaint oneself with the natural history of the place. Armed with a respect and appreciation for the landscape before you, you just might treat it a bit more reverently while you’re here and help ensure it remains for future generations to behold for many years.

The Landscape

The beginnings of Acadia National Park as we see it today are perhaps a half billion years old. At that time, deep wells of liquid rock known as magma were moving upward, exploding in underground volcanoes, then hardening—still underground, mind you—into granitelike rocks. Later, as natural forces such as wind and water wore away the upper layers of rock above these rocks, the rocks began to be exposed. Their journey was only beginning, however; soon enough (geologically speaking, that is), what is now eastern North America and most of Europe began to shove up against each other, slowly but inexorably. This “collision” (which was more like an extremely slow-motion car wreck), heated, squeezed, transformed, and thrust up the rocks that now form the backbone of Mount Desert Island.

Now in place, the rocks were once again changed by everything around them. Ice ages came and went, but the rocks remained; the successive waves of great glaciation and retreat scratched up the rocks like old vinyl records, and the thick tongues of pressing ice cut deep notches out of the rock. Near Somesville it nearly divided the island in two, creating the only natural fjord in the United States; farther “inland,” the slowly flowing ice pushed forward and scooped out several more narrow, parallel valleys that would later be filled by rainwater to form Jordan Pond and Eagle Lake. Huge boulders were swept up and deposited by the ice in odd places, such as the tops of mountains (Bubble Rock is one).

Acadia National Park

When the glaciers finally retreated for the last time, tens of thousands of years ago, the water melting from the huge ice sheet covering North America swelled the level of the Atlantic high enough to submerge formerly free-flowing river valleys and give Mount Desert Island the distinctive, knuckled-fist shape we know it for today.

Onto the bones of this landscape came plants and then animals. After each ice age, conifers such as spruce and fir trees—alongside countless grasses and weeds—began to reform, decompose, and form soils. It was tough work: Acadia is a rocky, acidic place. Yet they persevered, and soon the spruces, firs, and hemlocks formed an impenetrable thicket covering the bedrock. Land animals came here, too, some of them now extinct from the island—the caribou, elk, eastern timber wolf, and sea mink among those extirpated by human presence. Many others survived, however, and there’s plenty of wildlife here today; while the lynx and eastern cougar may no longer roam the woods, hills, and fields of Acadia, plenty of other creatures do.

Rising from the Ashes

The park, though it appears to be fixed in time now, is actually in constant flux. Islanders got a lesson in nature’s restorative powers in 1947, when a huge forest fire swept across the park and island, devastating most of it. In the ashes soon grew not more spruces and firs, but rather an entire new set of flowers, weeds, and trees better adapted to grow in bright, sunny, nutrient-poor meadows. Fireweeds, wildflowers, aspens, birch, oak, pine, and maple trees began to slowly fill in the denuded landscape and today help create the mixture of plants (and the fall foliage, and the deer, mice, and other animals that favor this mixture) in the park today. The spruces and firs may eventually take over again—but it will take generations to happen.

Acadia’s unique position—it is very near the warm Gulf Stream, yet possesses very cold waters; it is not far from the high, shallow undersea plateau known as Georges Bank—has also brought an astonishing variety of marine life to its doorstep. Migrating whales make for a wonderful spectacle twice each year (and whale-watching tours out of Bar Harbor bring the lives of whales closer to the visitor). Seabirds make similar passages, lighting upon the rocks and lakes of the park coming and going. And the waters teem—though not as they once did—with fish large and small, lobsters, crabs, dolphins, and a great deal more (each creature with its particular habits, habitats, diets, life cycles, and seasonal migration patterns).

Tide pool, Acadia National Park, Maine

This is to say almost nothing of Acadia’s tide pools (pictured above), in that precarious zone where land and rock meet crashing ocean; a closer look at these pools reveals an ever-changing world of seaweed, snails, barnacles, darting water bugs, clams, shellfish, mud-burrowing worms, and other creatures. Interestingly, the type of life you’ll find changes in well-marked “bands” as you get closer to water; rocks that are always submerged contain one mixture of seaweeds and marine organism, rocks that are exposed and then resubmerged each day by the tides contain another. Mostly dry surfaces of the shore rocks contain yet another mixture of living things. It’s fascinating to note how each particular organism has found its niche, maintained it, and continues to live hardily and well—within its particular band. Move it up or down a foot, and it would perish.

The Flora

BALSAM FIR: The best-smelling tree in the park must be the mighty balsam fir, whose tips are harvested elsewhere to fabricate aromatic Christmas-tree wreaths. It’s sometimes hard to tell a fir from a spruce or hemlock, though the balsam’s flat, paddlelike needles (white underneath) are nearly unique—only a hemlock’s are similar. Pull one off the twig to be sure; a fir’s needle comes off clean, a hemlock’s ragged. Still not sure you’ve got a fir tree on your hands? The long, glossy, almost purplish cones are absolutely distinctive.

RED, WHITE, AND PITCH PINE: The pines grow in Acadia’s sandy soils and normally like some sunlight. White pine is the familiar “King’s pine” prevalent throughout Maine; its trunk was prized for the masts of British ships of war, and countless huge pines were floated down Maine rivers by logger men. Sadly, very few virgin pine trees remain in Maine today. The white pine’s extremely long, strong needles come five to a bunch. The red pine, not so common, can be distinguished by its pairs of needles and pitchy trunk. The presence of a pitch pine indicates poor, acidic soils—this is one of the first trees to successfully rush in and take root in the wake of a fire. It can grow in the oddest places—along a cliff, on a lip of crumbling stone, in waste soil. The shorter, scrubby clumps of needles (arranged three to a group) don’t look attractive but belie the tree’s toughness.

Sugar Maple

RED AND SUGAR MAPLE: These two maple trees look vaguely alike when turning color in fall, but they’re actually quite different—from the shapes of their leaves to the habitats they prefer. Red maples have skinny, gray trunks and like a swampy or wet area; often, several of the slim trunks grow together into a clump, and in fall the red maples’ pointy leaves turn a brilliant scarlet color almost at once. Sugar maples (pictured above), on the other hand, are stout-trunked trees with lovely, substantial leaves (marked with distinctive U-shaped notches), which autumn slowly changes to red and flame-orange. Sugar maples grow in or at the edges of mixed forests, often in combination with birch trees, oak trees, beech trees, hemlocks, and the like. Their sap, of course, can be collected and boiled down to make delicious maple syrup.

Blueberries in Maine

LOWBUSH BLUEBERRY[em]The lowbush blueberry, with its shrubby, tealike leaves and hardy, thick twigging, lies low to exposed rocks on sunny hillsides or sometimes crops up in shady woods; most of the year, it’s inconspicuous as anything, trailing harmlessly underfoot. Come late summer, however, it’s suddenly the island’s most popular plant—among bears as well as humans. The wild blueberries ripen slowly in the sun (look behind and beneath the leaves for the best bunches), and make for fine eating, pancake baking, and jam.

The Fauna

BEAVER: Reintroduced to Acadia in the 1920s (it had earlier nearly gone extinct from brisk world trade in beaver pelts), the beaver’s lodge-building, stick-chewing, and hibernating habits are well known. You’ll find it in streams, lakes, and ponds around Mount Desert Island.

Black bear cub

BLACK BEAR: Black bears do appear in Acadia, though in small numbers (still, you may want to keep a cover on that campfire food). The bears are mostly—emphasis on mostly—plant-eaters and docile. Though they’ll eat just about anything, black bears prefer easily reached foods on the woodland floor such as berries, mushrooms, and nuts. They need them for a long winter hibernation that averages 6 months.

MOOSE: Nothing says Maine like a moose. The huge, skinny-legged, vegetarian moose is only sporadically seen on Mount Desert Island—it is an island, after all—but you may well run into one in the Schoodic Peninsula unit of the park. For the most part, the moose far prefers the deep woods, lakes, ponds, and uninhabited areas of Maine’s Great North Woods.

FINBACK WHALE: A seasonal visitor to Maine’s waters twice a year when migrating between polar and equatorial waters, the finback is one of the biggest whales, and also one of the most collegial. It often travels in pairs or groups of a half-dozen or more (most whales are relatively solitary), though it does not travel close to shore or in shallow waters; you’ll need a whale-watch boat to spot it. Find it by its rather triangular head and a fin that sweeps backward (like a dolphin’s) rather than standing straight up like many other whales’.

HUMPBACK WHALE: Though this whale’s Latin name roughly translates as “large-winged New England resident,” the gentle, gigantic humpback actually isn’t so often seen off the coast of Acadia. (That’s mostly because they were easy targets in the heyday of whaling.) But if you do see it, you’ll know it: It’s huge, dark black, blows tremendous amounts of water when surfacing, and does some amazingly playful acrobatics above water. The males also sing haunting songs, sometimes for as long as 2 days at a time. The world population has shown signs of a rebound since protections went into place in the 1960s; there are maybe 12,000 individuals in the North Atlantic.

Minke Whale

MINKE WHALE: Pictured above, the smallest (and most human-friendly) of the whales, the minke swims off Acadia’s coast, usually moving in groups of two or three whales—but much larger groups collect in feeding areas and seasons. It has a unique habit of approaching and congregating around boats and ships, making this a whale you’re quite likely to see while on a whale-watching tour. The minke is dark gray on top; the throat has grooves; and each black flipper fin is marked with a conspicuous white band.

NORTH ATLANTIC RIGHT WHALE: If you see a North Atlantic right whale, you’ve really seen something: It’s the most endangered of all the living whales—there are probably only a few hundred left—yet one has occasionally been seen off the coast of Acadia. Experts predict it will become extinct within a few more human generations, if not sooner. Huge and active as the humpback, the right is known for doing headstands (so to speak) underwater, poking its tail fins above. It can be spotted by its light color—often blue, brown, or even off-white—and the whitish calcium growths that often appear on its head.

PILOT WHALE: A small whale, the pilot is very rarely seen off Acadia, and very poorly understood. Its habits, world population, and diet are nearly unknown. It is known to congregate in large groups, sometimes consisting of up to several hundred, and even to swim with other species of whale at sea. Nearly unique among the whales that pass Maine, it has teeth, and the roundish fin is swept back like a dolphin’s or shark’s. Sightings are possible and should be cherished.

HARBOR SEAL: Related to sea lions, the whiskered harbor seal is best seen by using one of the charter boat services that leaves from Bar Harbor and other local harbors. You can also sometimes see it basking in the sun or on the rocks of an offshore island. You’ll easily recognize it: The seal’s flippers have five claws, almost like a human hand; its neck is stocky and strong (as are its teeth); and then there are those whiskers and that fur.


DUCKS: Between one and two dozen species of ducks and ducklike geese, brant, and teal seasonally visit the lakes, ponds, and tidal coves of Acadia every year, including—though hardly limited to—the red-breasted merganser, common eider, and the bufflehead. Mergansers, characterized by very white sides and very red bills (males) or reddish crests (females), occur year-round in the park but are more common in winter months. So is the eider, which inhabits offshore islands and coastal waters rather than Mount Desert Island’s freshwater lakes; Maine is actually the southernmost tip of its breeding range—in winter, it forms huge rafts of birds. Males are marked with a sharp black-and-white pattern. The chubby, squat bufflehead is also distinctively black and white, with a glossy green-and-purple head; it is entirely absent from the park in summer, but passes through in spring and fall, sometimes lingering for the winter. It flies much more quickly than one might imagine from its appearance.

Great Blue Heron

GREAT BLUE HERON: Everyone recognizes a great blue (see above) at once by its prehistoric flapping wings, comb of feathers, and spindly legs. These magnificent hunters wade tidal rivers, fishing with lightning strikes beneath the surface, from May through around October. The smaller, stealthier green heron occurs less commonly, and occasional sightings of black-crowned and yellow-crowned night herons have also been recorded within the park’s boundaries.

LOONS: Two species of loon visit the island’s lakes and tidal inlets, fishing for dinner. The red-throated loon, grayish with a red neck, is mostly a spring visitor and barely present at all in the heat of summer. The common loon is indeed more common—it can be distinguished by a black band around the neck, as well as black-and-white stripes and dots—and can be found in Acadia year-round, though it’s most easily spotted in late spring and late fall. It gives the distinctive mournful, almost laughing cry for which the birds are famous. Both have been decimated by human environmental changes such as oil spills, acid rain, and airborne mercury.

PLOVERS: Plovers inhabit and breed in Acadia’s muddy tidal flats, and their habitat is understandably precarious; a single human step could crush an entire generation of eggs. Only two species of plover visit the park, and they’re here in significant numbers for only a relatively short time. The black-bellied plover—marked with a snowy black-and-white pattern—arrives in May, breeds in August and September, and is gone by Thanksgiving. The semipalmated plover, with its quite different brownish body and white breast, has a similar life cycle.

SEAGULLS: No bird is so closely associated with Maine as the seagull. But, in fact, there’s more than one kind of gull here; three or four distinct gulls are commonly found here year-round, a few more visit seasonally, and a few more pop up occasionally. Most common is the grayish herring gull, which is also the gull least afraid of humans. It’s found in prevalence every month of the year. The aggressive great black-backed gull is similarly common, and is nearly all white (except for that black back and wings); it will even eat the eggs of another gull, but in general avoids humans. Less common are the glaucous, ring-billed gull, and even the laughing and Bonaparte’s gulls (in summer only), not to mention the related black-legged kittiwake. Each has a distinctive look; consult a bird guide if you’re interested in telling them apart.

STORM PETRELS: The tiny storm petrel is a fascinating creature. These plucky little birds fly astonishing distances in winter, eating insects on the wing, only to return to Acadia each spring like clockwork, usually in May. They spend an amazing 4 months in the nest incubating, hatching, and tending to their single, white eggs. Wilson’s storm petrel is here for a shorter time than the Leach’s storm petrel, which restricts its visits and nests solely to offshore rocks and islands. Both breed in the height of summer, then pack up and head south again by fall.

Land Birds

BALD EAGLE: Yes, they’re here—year-round—and even breed in Acadia, though they’re difficult to find and hardly conspicuous. (Their endangered status means you shouldn’t really try to seek them out.) The bald eagle’s black body, white head, and yellow bill make it almost impossible to confuse with any other bird. It was nearly wiped out by the 1970s, mainly due to environmental poisons such as DDT-based pesticides, which caused female eagles to lay eggs that were too weak to sustain growing baby chicks. However, the bird has made an impressive comeback.

COMMON RAVEN: The park holds jays and crows aplenty, but the raven is a breed apart—tougher, more reclusive, more ragged, more interesting. Look (or listen) for it on cliff tops, mountains, and in deep woods.

Black capped chickadee

SONGBIRDS: There are literally dozens of species of songbirds coming to roost in Acadia’s open fields, forests, and dead snags—even in the rafters and bird boxes of houses. They are not so common on this rocky, shady island as in Maine’s suburbia (Greater Portland, for instance) or in the farmlands of central and western Maine, but they are here. One thing is for certain: Songbirds love human company, thus look for them near the settled areas. The park hosts perhaps 15 or more distinct types of chirpy little warblers, each with unique and often liquid songs; a half-dozen thrushes occurring in significant numbers; winter wrens, swallows, sparrows, vireos, finches, creepers, and thrashers; the whimsical black-capped chickadee (see above); and occasional (and lovely) sightings of bluebirds, cardinals, and tanagers, among many other species.


Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.