Black-crowned Night-Heron

Although the Black-crowned Night-Heron is not currently known to breed in New Hampshire, it did so as recently as the 1980s. During this time there were a handful of known or suspected colonies in the southeastern corner of the state and suggestive sightings inland. After that the only known nearby nesting was on Appledore Island in the Maine portion of the Isles of Shoals, and at Plum Island, Massachusetts. Birds from these colonies continue to feed along the New Hampshire coast and are supplemented by post-breeding dispersal of adults and young in August and September. It is during the latter period that night-herons are most likely to appear inland, usually along the major river valleys.

As their name implies, night-herons are more nocturnal than other herons, although they will also forage during the day. At colonies where they co-occur with diurnal egrets and ibis, they take the night shift, with the night-herons departing as (or after) the other species return to roost for the night. During this transition, they are often first detected by their guttural “quok” call, and then perhaps seen silhouetted against the twilight sky. Preferred foraging habitats include salt marsh and mud flats, where they search for fish and invertebrates.

Why New Hampshire lost its nesting night-herons is unclear, although like other members of its family it is sensitive to disturbance. Because most of the historic colonies were in more populated areas near the coast, it’s possible that the pressures of a growing human population for too much, and birds were increasingly restricted to more remote areas. The lack of suitable remote islands in the state was likely a contributing factor. There is also a lot of evidence that Black-crowned Night-Herons accumulated toxic chemicals such as DDT, although there are few detailed studies on any direct effects.