Outer Green Island, Casco Bay

Maine · Northeast

ChallengingView on eBird Directions

Habitat

Coastal

Best Seasons

Spring Fall

Difficulty

Challenging

Best Months

April-May, September-October

About This Location

Outer Green Island, Casco Bay is a productive birding destination in Maine, with 201 species recorded on eBird. This coastal habitat attracts a wide variety of species among many others. Spring and fall migration bring waves of warblers and shorebirds through the area.

Location

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Notable Species

Sanderling Brown Pelican Osprey Royal Tern Willet

Live Bird Data

Notable Sightings

Rare or unusual species spotted nearby in the last 14 days

Blue Grosbeak

Passerina caerulea

5/31/2026Outer Green Island, Casco Bay1 observed

Little Gull

Hydrocoloeus minutus

5/31/2026Biddeford Pool--Sky Harbor Dr.2 observed

Atlantic Puffin

Fratercula arctica

5/30/2026Outer Green Island, Casco Bay2 observed

Caspian Tern

Hydroprogne caspia

5/30/2026Portland Head Light--Fort Williams Park3 observed

Black Tern

Chlidonias niger

5/30/2026Biddeford Pool--Sky Harbor Dr.1 observed

Common Murre

Uria aalge

5/30/2026Dyer Point2 observed

Sooty Shearwater

Ardenna grisea

5/30/2026Dyer Point1 observed

Black-necked Stilt

Himantopus mexicanus

5/30/2026Stratton Island1 observed

Recent Observations

Species reported at this location in the last 14 days

Mallard

15/31/2026

Common Eider

1055/31/2026

Black Scoter

185/31/2026

Long-tailed Duck

35/31/2026

American Oystercatcher

55/31/2026

Spotted Sandpiper

35/31/2026

Ruddy Turnstone

25/31/2026

Black Guillemot

285/31/2026

Razorbill

25/31/2026

Laughing Gull

25/31/2026

American Herring Gull

55/31/2026

Great Black-backed Gull

45/31/2026

Common Tern

5/31/2026

Roseate Tern

15/31/2026

Common Loon

35/31/2026

Double-crested Cormorant

305/31/2026

Great Blue Heron

15/31/2026

Bank Swallow

125/31/2026

Barn Swallow

15/31/2026

Song Sparrow

65/31/2026

Birding Tips

1
Check rocky shorelines and jetties at low tide for shorebirds.
2
Scan offshore waters with a spotting scope for seabirds and waterfowl.
3
Visit during mid-May for peak warbler migration.

Amenities

Parking

Trails

More in Maine

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Acadia National Park - Otter Point

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Maine Birding Guide

Complete guide to birding in Maine →

Birding Guides

Fall Bird Migration Guide

10 min read

Understanding Bird Migration

12 min read

Spring Birding in New York City

12 min read

Frequently Asked Questions

When is the best time to visit Outer Green Island, Casco Bay for birding?▼

The best months to visit Outer Green Island, Casco Bay for birding are April-May, September-October. The best seasons are Spring and Fall.

What birds can I see at Outer Green Island, Casco Bay?▼

Notable species at Outer Green Island, Casco Bay include Sanderling, Brown Pelican, Osprey, Royal Tern, Willet. The area supports coastal habitats.

How difficult is birding at Outer Green Island, Casco Bay?▼

Birding at Outer Green Island, Casco Bay is rated as Challenging. The terrain can be challenging and may require good physical fitness and preparation.

What amenities are available at Outer Green Island, Casco Bay?▼

Outer Green Island, Casco Bay offers the following amenities: Parking, Trails.