The causeway leading to Sears Island is accessible for roadside birding, however, the island itself can only be accessed by foot. Seabirds can be viewed from the causeway and beaches around the island. The central road is paved, easy walking, and good for songbirds during migration.

Birders have spotted over 220 species of birds on Sears Island, representing approximately 47% of all bird species recorded in Maine.

Sears Island, known as Wassumkeag, lies within traditional Penobscot lands (Native American Tribes of Maine). The island is characterized by a maritime spruce-fir forest, and mature hardwood forests, which afford habitat to specific kinds of birds, mammals, invertebrates, and understory plants. Although it is not an Old Growth forest, having been farmed in the 19th and early 20th centuries, there are some large old trees that have reforested the land.