Birding in Acadia National Park

Acadia National Park sits within the Atlantic Flyway, one of North America's major bird migration corridors, and has recorded more than 338 species across its varied habitats. That number reflects not one type of habitat but many: ocean coast and rocky intertidal, freshwater lakes and beaver wetlands, spruce-fir forest and mixed hardwood, tidal flats and sheltered harbors, and the exposed granite summits of the mountains themselves.

The diversity of habitat types compressed into a relatively small geographic area — Mount Desert Island is roughly 108 square miles — means that a birder can move through dramatically different ecosystems within the span of a morning. Breeding species, long-distance migrants passing through, and wintering seabirds all use the park at different times of year. No month is without something worth seeing.

The Atlantic coast provides a concentration effect during migration: birds moving south in fall or north in spring funnel along the coastline, and headlands like the Schoodic Peninsula or the Cadillac summit become natural congregation points during fallout events. September and October consistently produce the highest species diversity of any period in the park calendar.

Peregrine falcons were extirpated from the entire northeastern United States by the early 1960s. The cause was DDT — the pesticide accumulated in the bodies of the prey birds peregrines ate, and at high enough concentrations it caused eggshell thinning severe enough that incubating adults crushed their own eggs. By 1964, no confirmed nesting pairs remained east of the Mississippi.

After DDT was banned in 1972, recovery efforts began through captive breeding programs at Cornell University and elsewhere. Young birds were hacked — raised in artificial nest boxes mounted on cliffs and gradually released to hunt on their own — at sites across New England, including the Champlain Mountain cliffs in Acadia. The Maine reintroduction program began in earnest in the 1980s.

Peregrines have nested successfully on the Precipice cliffs every year since the reintroduction took hold. The annual trail closure that frustrates some hikers — typically mid-March through mid-August, depending on nesting activity — is the direct mechanism of that success. The NPS closes the Precipice and sometimes the Beehive trails during active nesting to prevent human disturbance of the nest site. The birds are there because the closures work.

Atlantic puffins do not nest on Mount Desert Island. Their nesting colonies require remote offshore islands with minimal predator pressure and specific substrate for burrowing — conditions that exist on several protected islands further offshore. The closest reliable puffin colonies to Bar Harbor are managed by the Audubon Society’s Project Puffin, which reestablished colonies on Eastern Egg Rock beginning in 1973 and on other islands since.

Boat tours depart from Bar Harbor and from Milbridge (approximately 45 minutes east along the coast) to reach puffin nesting islands. The season runs late May through early August, when the birds are present on land and actively nesting — after August the puffins return to sea for the winter and become essentially impossible to find. Look for tours with naturalist guides who can explain puffin biology and the extraordinary restoration effort that brought them back to Maine.

Verify current tour operators and scheduling directly before your visit. Operators change season to season, and departure points, pricing, and availability are best confirmed through current sources.

eBird, maintained by the Cornell Lab of Ornithology, is the most practically useful tool available to birders visiting Acadia. It aggregates real-time sighting reports from birders across the park and displays them on a map by location, date, and species. Before heading to a specific location, a quick check of recent sightings shows exactly what other birders have found there in the past week.

The Explore feature lets you filter by species — if you specifically want to find a Red Crossbill or a Bohemian Waxwing that someone reported, you can see precisely where and when the sighting occurred. During fall migration, checklists submitted by birders at Cadillac summit or the Schoodic Peninsula provide near-real-time information about what is moving through.

Download the eBird app and use its offline map function before leaving cell range. Most locations in the park have no data reception, and having offline hotspot maps loaded means you can still navigate to specific productive locations even without signal.