Northern Harrier
(Circus hudsonius)

Summary

Picture of bird
© Jukka Jantunen (flickr.com/photos/jukka_jantunen)
For additional photos and vocalizations, visit Dendroica. (Link opens in a new window.)

The Northern Harrier is widely distributed across Canada and nests on the ground in densely vegetated wetlands or grasslands. The species is well monitored by the Breeding Bird Survey (BBS). BBS results indicate a widespread, moderate decrease in population since about 1970. The species is susceptible to pesticide exposure and has also suffered as a result of extensive drainage of wetlands. This species has been identified as a priority for conservation and/or stewardship in one or more Bird Conservation Region Strategies in Canada.

Designations

Main designations for the species
DesignationStatusDateSubspecies, population
COSEWIC (Canada)Not at Risk1993 
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 DecreaseHighBelow Acceptable Level
 

Population estimate

Geographic area or populationPopulation estimate
Canada50,000 - 500,000 adults
 

Distribution maps

 

Migration strategy, occurrence

Short-distance migrant

Responsibility for conservation

Geographic areaResponsibility based on % of global population
CanadaModerate

General nesting period in Canada

Nesting period starts between late March and early June and ends between mid-July and early August, depending on the region. Before or after this period, the probability of an active nest is lower.
 

Conservation and management

Like many birds of prey, Northern Harriers suffered reproductive failure and population decline in the mid-twentieth century as a result of organochlorine pesticide application (Smith et al. 2011). Currently, habitat loss and degradation are major threats to the species' conservation: loss of freshwater and estuarine wetlands, loss of open prairie habitat, and agricultural intensification are thought to reduce prey availability and the availability of safe, suitable nesting habitat (Smith et al. 2011). The effects of climate change (e.g., warmer, drier conditions) could potentially also result in changes in the spatial and temporal availability of wetland habitat across the species' breeding range (e.g., Thompson et al. 2017). Northern Harriers can exhibit nomadic behaviour as they search for suitable nesting and foraging habitat.

 

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 Taiga PlainsBoreal Taiga Plains, sub-region and priority type: Prairie and Northern -- Conservation
Great BasinGreat Basin, sub-region and priority type: Pacific and Yukon -- Stewardship
Lower Great Lakes/St. Lawrence PlainLower Great Lakes/St. Lawrence Plain, sub-region and priority type: Ontario -- Conservation
Lower Great Lakes/St. Lawrence PlainLower Great Lakes/St. Lawrence Plain, sub-region and priority type: Quebec -- Conservation
Northern Pacific RainforestNorthern Pacific Rainforest, sub-region and priority type: Pacific and Yukon -- Conservation
Northern RockiesNorthern Rockies, sub-region and priority type: Pacific and Yukon -- Conservation
Prairie PotholesPrairie Potholes, sub-region and priority type: Prairie and Northern -- Conservation & Stewardship
 

References