Black-crowned Night-Heron

Nycticorax nycticorax

Black-crowned Night-Herons are colonial breeders and gregarious throughout the year, often associating with other species of herons (Davis 1993). Breeding colonies are typically located near or over water in dense cover such as willows or herbaceous vegetation. Nests in trees are frequently at heights of less than 5 meters (Meyerriecks 1960). Most colony sites are occupied for a number of years.

Code Frequency

Rare breeders in Missouri (Robbins and Easterla 1992), Black-crowned Night-Herons were confirmed to breed in only one block during the seven-year Atlas Project. The numerous possible records shown on the map were likely not actual breeding locations for several reasons. Black-crowned Night-Herons characteristically disperse widely in late summer after breeding (Custer and Osborn 1978). They also travel up to 24 kilometers from breeding locations to feed (Hoefler 1979). Additionally, the Missouri Department of Conservation staff surveyed for breeding locations annually 1986-1990, and likely were aware of the majority of colonies outside of blocks.

Distribution

Evidence was found at too few locations to reveal any regional differences in Black-crowned Night-Heron distribution. They were found, outside of Atlas Blocks, in four mixed-heron/egret breeding colonies in Scott, Mississippi and Pemiscot counties. However, this information should not be construed to imply they are primarily residents of southern Missouri. Likewise, data are insufficient to reveal abundance details except that Black-crowned Night-Herons are rare breeders in Missouri.

Abundance

Surveys of known colonies outside of Atlas blocks indicated up to 50 individuals in two Scott County sites, and 15-100 and 55-60 in the Mississippi and Pemiscot county sites, respectively.

Breeding Evidence

Reported in 14 (1.2%) of 1,207 blocks

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