Acadia National Park

Acadia National Park

Nature & Wildlife

Not just any species of plant or animal can adapt to the ecological demands of Acadia’s overlapping environments, but Acadia’s flora and fauna have flourished. Most of the park’s animals are adept at avoiding detection, but look carefully (and quietly) at dawn or dusk and you may see them feeding.

The Forest

For centuries, evergreens dominated much of northern Maine. When the last glacier receded, spruce and balsam firs outnumbered such deciduous trees as birch and aspen. These coniferous trees inhibited the growth of other vegetation with their long shadows and needles, which, as they decayed, produced acidic soil.

These resinous trees are also especially quick to burn and slow to regenerate. Following the 1947 fire, a new forest of sun-worshipping birch, maple and aspen sprang up amid the surviving evergreens. Thus, the fire increased the diversity of Acadia’s woodlands and the intensity of its fall foliage. As they grow, the deciduous trees produce the shade required by evergreens, and eventually spruce and fir will stand tall once more in Acadia.

Of the evergreens, red spruce still predominates. Ramrod straight with reddish-brown bark and sharp, stiff needles, it can grow as tall as 75 to 110 feet—although on Acadia’s rocky mountaintops, dwarf spruce one-tenth that size are common. Outside the park, red spruce is heavily logged for pulp. White spruce, which has silvery-brown bark and bluish-green needles, is also found here.

Of course, it is no accident that Maine is known as the “Pine Tree State.” Several species thrive in Acadia, including red, pitch and jack pines. But the best known is the white pine, which unlike spruce and fir, prefers sunlight to shadow. White pine grows quickly, usually to heights of more than 100 feet. Because of its great size, it was once highly valued for sailing ship masts.

To Acadia’s earliest inhabitants, no tree was more important than the paper birch. They used the birch’s tough, white bark to craft baskets, canoes and wigwams. Prized by native tribes and settlers alike was the sugar maple, whose sweet sap produces that New England delicacy, maple syrup.

The Water's Edge

Acadia’s intertidal zone teems with marine life that has adapted to Acadia’s twice-daily tides, which range between 10 and 12 feet.

Just below the low-water mark is kelp, a dense, brown seaweed that can withstand 600 pounds of water force per square inch before breaking. Sheltered by the kelp are crabs, sea urchins, sea anemones, starfish and jellyfish.

Next closest to shore is Irish moss, a bushy, purplish-brown seaweed. When processed, it becomes carrageenan, a thickening agent used in ice cream, cheese, salad dressing and chocolate milk.

At the high-water mark, you’ll find a white layer of acorn barnacles. These minute crustaceans float to shore and attach to rocks, ship bottoms and pilings, then they form a tough, conical shell. Periwinkles, tiny snails half an inch long, feed on wet algae with a rough tongue called a radula.

A lichen, pale gray in color and known as old man’s beard, festoons the spruce trees that grow near shore. Like their mountaintop cousins, the trees and plants that grow along the coast are often dwarfed and twisted—the result of fierce winds and highly saline ocean spray.


The park boasts close to 50 species of land and marine mammals, reptiles and amphibians. 

White-tailed deer are plentiful in Acadia. Tall and graceful, with a tan coat and a tail with a white underside, the deer feed on grasses and tree buds. 

One of the white-tailed deer's natural predators is the eastern coyote, a buff-colored canine that resembles the wolf but has a smaller build, narrower muzzle and larger ears. Since the 1960s, the coyote's numbers have been increasing in Maine, leading some to call for this predator's eradication—a position much criticized by environmentalists. While the coyote is not common on Mount Desert Island, many residents report hearing its distinctive, high-pitched "singing" at night. You may see the red fox hunting hare and small rodents in open fields and salt marshes, or darting across the park's roads and carriage roads by night. During the fall and winter, its red-brown coat becomes thick and richly colored.

When cold weather approaches, the non-burrowing snowshoe hare molts its gray-brown coat and grows white fur, excellent camouflage against the winter snow. The toes of its hind feet splay apart to form natural "snowshoes." 

Heavily trapped for its fur during the last century, the beaver had all but disappeared from Mount Desert Island. Local legend has it that Acadia owes its present healthy population to just two pairs of beavers released in 1920 by the park's first superintendent, George Dorr. These large, broad-tailed rodents build dams year round. In September, they start reinforcing their lodges and building food caches to prepare for winter. The best time to see beavers is at dusk when they come out to forage and cut trees. From Park Loop Road, you can see beaver lodges in Beaver Dam Pond near Bear Brook Picnic Area.

Moose are uncommon in the park, though you might see one in Acadia's second-growth boreal forests with semi-open areas and swamps or lakes.

Marine Wildlife

The playful harbor seal is five to six feet in length with gray-brown fur. These marine mammals are sometimes spotted at low tide by boat, basking in the sun on offshore ledges and islands, especially in late spring or early summer whelping season. At high tide, they take to the water to catch herring, mackerel and other North Atlantic fish.

Some of the most commonly seen whales include the finback, which ranges from 30 to 70 feet in length and has a distinctive white stripe across the right side of its jaws; the humpback, which is 30 to 60 feet in length and is noted for its acrobatic behavior, knobby head and snout; and the smaller minke, which is usually less than 20 feet in length. Puffins aren't visitble from Mount Desert Island on Mt. Desert Island, but they do live on islands along Acadia's coast. Many of these creatures may be seen during popular whale watching cruises.


Acadia is known for its great birdwatching. Located at the juncture of the northern and temperate life zones, Acadia attracts more than 300 species of sea, shore, and land birds, from the common loon to the majestic bald eagle and peregrine falcon. Sea ducks also frequent the coastal waters, particularly during the winter months. Of particular note are buffleheads, red-breasted mergansers, common eiders, black scoters, surf scoters and white-winged scoters. The bufflehead has a puffy, bonnet-shaped brow, while the sleek merganser has a crested, almost punkish coiffure. Surf scoters are known as “skunk ducks,” not because of their scent but rather for their black-and-white markings.

Black guillemots are distinct both in sight and sound—they have brilliant red feet, white wing patch and raucous squawks. These impressive birds nest on Long Porcupine Island and are visible along its steep ledges. Guillemots can dive as deep as 165 feet to catch their favorite treats—cod and mollusks.

Dozens of brightly colored warblers summer in Acadia, filling the woods with their cheerful songs.