Cassin's Vireo
(Vireo cassinii)


Picture of bird
© Tony Battiste
For additional photos and vocalizations, visit Dendroica. (Link opens in a new window.)

The Cassin's Vireo was recognised as a distinct species in 1997 when the "Solitary Vireo" complex was split into Cassin's, Blue-headed, and Plumbeous Vireos (American Ornithologists' Union 1997). In Canada, the Cassin's Vireo is largely restricted to the southern half of British Columbia. The species is monitored well by the Breeding Bird Survey. The Canadian population has shown little overall change since the early 1970s, despite fluctuating widely among years. 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
CanadaLittle ChangeHighAt an Acceptable Level

Population estimate

Geographic area or populationPopulation estimate
Canada1,000,000 - 5,000,000 adults

Distribution maps


Migration strategy, occurrence

Long-distance migrant

Responsibility for conservation

Geographic areaResponsibility based on % of global population

Conservation and management

The Cassin's Vireo breeds in coniferous and mixed woodlands, usually those with an open character (Campbell et al. 1997). Since this species tolerates a variety of silvicultural practices, responding neutrally or favourably to thinning and selective logging, there are few management concerns over much of its range (Goguen and Curson 2002). Recent climatic changes and drier winters in the species' breeding range may be contributing to better conditions for the species (Ray et al. 2017).


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
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 -- Stewardship