Black-crowned Night-Heron
(Nycticorax nycticorax)


Picture of bird
© Mike Baird - License
For additional photos and vocalizations, visit Dendroica. (Link opens in a new window.)

A generalist that forages on a variety of organisms (e.g., fish, invertebrates, amphibians, small mammals) at dawn and dusk as well as overnight, the colonial Black-crowned Night-Heron breeds in the prairies and in the Great Lakes/St. Lawrence area. The Breeding Bird Survey suggests that there has been an overall decrease in numbers since 1970, with some regional variability. This species has been identified as a priority for conservation and/or stewardship in one or more Bird Conservation Region Strategies in Canada.


Main designations for the species
DesignationStatusDateSubspecies, population
IUCN (Global)Least concern2018 
Wild Species (Canada)Secure2015 
Bird Conservation Region StrategyPriority Species2013 

Population status

Geographic area or populationPopulation change relative to ~1970ReliabilityStatus in relation to goal
CanadaModerate DecreaseMediumBelow Acceptable Level

Population estimate

Geographic area or populationPopulation estimate
Canada10,000 - 25,000 breeding birds

Distribution maps


Migration strategy, occurrence

Short-distance migrant

Responsibility for conservation

Geographic areaResponsibility based on % of global population
CanadaVery Low

General nesting period in Canada

Nesting period starts between mid-April and mid-May and ends in mid-August, depending on the region. Before or after this period, the probability of an active nest is lower.

Conservation and management

The Black-crowned Night Heron’s diet of fish and other aquatic organisms leaves it vulnerable to contaminant-induced reproductive failure, although concentrations of pesticides and other industrial toxins may rarely be high enough to impede breeding (Hothem et al. 2010). Human impacts on coastal and wetland environments and the habitat alteration expected with future climate change also pose a threat (Hothem et al. 2010), while interspecific competition with Double-crested cormorants may restrict access to nesting sites and limit population growth (Cuthbert et al. 2002, Hothem et al. 2010). Management of cormorant populations on the Great Lakes can also negatively affect the Black-crowned Night-Heron, likely due to human disturbance (Wyman et al. 2018).


Bird conservation region strategies

Environment and Climate Change Canada and partners have developed Bird Conservation Region Strategies in each of Canada’s Bird Conservation Regions (BCRs). In these strategies, selected species are identified as priorities for one or more of the following reasons:

  • conservation concerns (i.e., species vulnerable due to population size, distribution, population trend, abundance, or threats)
  • stewardship responsibilities (i.e., species that typify the regional avifauna or have a large proportion of their range or population in the sub-region)
  • management concerns (i.e., species that require ongoing management because of their socio-economic importance as game species, or because of their impacts on other species or habitats)
  • other concerns (i.e., species deemed a priority by regional experts for other reasons than those listed above or because they are listed as species at risk or concern at the provincial level)

Select any of the sub-regions below to view the BCR strategy for additional details.

BCRs, marine biogeographic units, and sub-regions in which the species is listed as a priority
RegionSub-region and priority type
Boreal Hardwood TransitionBoreal Hardwood Transition, sub-region and priority type: Ontario and Manitoba -- Conservation
Boreal Taiga PlainsBoreal Taiga Plains, sub-region and priority type: Prairie and Northern -- Other
Lower Great Lakes/St. Lawrence PlainLower Great Lakes/St. Lawrence Plain, sub-region and priority type: Ontario -- Conservation
Northern Pacific RainforestNorthern Pacific Rainforest, sub-region and priority type: Pacific and Yukon -- Stewardship
Prairie PotholesPrairie Potholes, sub-region and priority type: Prairie and Northern -- Other