Heron Island is located two to three km off the northern shore of New Brunswick near the head of the Baie des Chaleurs (approximately 12 to 20 km southeast of the town of Dalhousie). The island is about 7 km long by 1.5 km wide, low-lying, and mostly wooded, although clearings have been created for access to several seasonal dwellings. The northwest tip of the island is marshy with tidal lagoons and adjoining meadow marshes. Several small rocky islands are located to the south of Heron Island, near the mouth of the Benjamin River. These rocky islands are important for nesting Common Eiders.
Heron Island supports a large colony of Double-crested Cormorants. The most recent survey, which was completed in 1986, yielded a population estimate of about 3,000 pairs (as much as 3.3% of the Atlantic coast population). A more recent census has not been completed. Based on the available data, it is reported to be the second largest colony in New Brunswick, and the third largest colony in the Maritimes. With the exception of Neotropic Cormorants, Double-crested Cormorants are the only North American cormorants that breed in both salt and fresh water. In the Maritimes, however, they nest primarily in marine environments. In addition to Double-crested Cormorants, it is also possible that Great Blue Herons and Black-crowned Night-Herons breed on Heron Island, although nesting has yet to be confirmed.
Of additional ornithological interest is the presence of approximately 250 Common Eiders that nest on the small rocky islands adjacent to the mainland (along the south shore of the Heron channel). This group of nesting eiders is the only colony between the St. Lawrence estuary population, and the southwest New Brunswick / Maine population. To the south, the next closest group of nesting Common Eiders is in Chignecto Bay, over 400 km away.
BirdLife International (2022) Important Bird Areas factsheet: Heron Island. Downloaded from http://www.birdlife.org on 05/07/2022.