Overview
The black-crowned night heron (Nycticorax nycticorax), a state-listed threatened species, once occurred in marshes and swamps throughout Ohio. The species has been eliminated as a mainland nester and presently is relegated to the Lake Erie Islands. They presently nest on West Sister Island NWR and Turning Point Island in Sandusky Bay.
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Description
The black-crowned night-heron is a stocky, thick-billed, and short-legged bird. When seen, it is usually hunched and inactive. The adult can be identified by its blackish back and black cap in contrast to pale gray underparts. The eyes are red and the legs are yellow or yellow-green. During the breeding season, they develop two long, white head plumes and their legs turn pink.
Reproduction
Black-crowned night-herons frequently breed in mixed colonies with other herons. Nest construction begins usually during April or May. Incubation of the 3-5 eggs lasts 24-36 days. Most young hatch during May, while the last nesting attempts may not produce young until the first half of June. Young fledge 6-7 weeks after hatching.
Habitat & Behavior
These largely nocturnal herons are likely more common than suspected, but tend to hide in thick vegetation during the day. At night, they often give a very distinctive, deep quawk call that reveals their presence. These herons are often found roosting in thick vegetation along streams, lakes, and wetlands. They are hardy and sometimes overwinter in favored spots. They typically eat fish, leeches, earthworms, aquatic and terrestrial insects.
Research & Surveys
2016 Update
The black-crowned night heron, a state-threatened species, is a wetland-obligate species that once occurred in marshes and swamps throughout Ohio. The majority of nesting night herons are found on West Sister Island National Wildlife Refuge and Green Island in Lake Erie, and Turning Point Island in Sandusky Bay. West Sister Island makes up the largest colony within the U.S. Great Lakes but has been steadily declining in size. The estimated colony size for 2015 in the Lake Erie Islands was 340 nesting pairs, down approximately 30% from the previous year. Management of cormorants and vegetation is ongoing in order for the colony to persist. In the past, inland breeding colonies have been reported near Cincinnati, Youngstown, Bucyrus, and Grand Lake St. Marys, but status of these is uncertain.
