Canada Warbler
(Cardellina canadensis)

Summary

Picture of bird
© Dan Busby
For additional photos and songs, visit Dendroica. (Link opens in a new window.)

Still fairly abundant and widespread, the Breeding Bird Survey indicates this primarily Canadian-breeding species has undergone a significant long-term, decrease since about 1970. That decrease, which led to the Committee on the Status of Endangered Wildlife in Canada assessment of Threatened in 2008, is thought to be due primarily to loss of breeding and wintering habitat (COSEWIC 2008a). With over 80% of the species' global breeding population, Canada's responsibility for the species is very high. This species has been identified as a priority for conservation and/or stewardship in one or more Bird Conservation Region Strategies in Canada.

Designations

Listing of the main designations for the species
DesignationStatusDateSubspecies, population
COSEWIC (Canada)Threatened2008 
SARAThreatened2010 
IUCN (Global)Least Concern2012 
Partners in Flight (North America)Stewardship List, Watch List Species2012 
Wildspecies (Canada)At Risk2010 
Partners in Flight (Tri-National Vision)High Tri-National Concern2012 
Bird Conservation Region StrategyPriority Species2013 

Population status

Geographic areaStatusReliability
CanadaLarge DecreaseMedium
 

Population estimate

Canada500,000 to 5,000,000 adults
 

Distribution maps

 

Migration strategy, occurrence

Long-distance migrant

Responsibility for conservation of world population

CanadaVery High

Conservation and management

The causes of declines in Canada Warbler populations are unclear. However, loss of wintering habitat in South America is likely a factor,  as well as loss and degradation of habitat on the breeding grounds including loss of forested wetlands and changes to the forest structure (e.g., loss of understory; Reitsma et al. 2010). More recently there is a suggestion that declines in Canada Warbler may be related to spruce budworm populations (Sleep et al. 2009) which have been in decline since the mid-1980s. Spruce budworm populations are known to be cyclical (Royama 1984) and can be expected to surge again to high levels in the near future (Royama et al. 2005). However, other studies suggest there is little evidence at the local scale that Canada Warbler responds strongly to budworm infestation (Venier and Holmes 2010). The Canada Warbler International Conservation Initiative is a new partnership that will further investigate the causes of population declines in this species and coordinate conservation efforts throughout its range. For information on the legal status of this species under the Species at Risk Act (SARA) and to view available recovery documents, see the SARA Registry.

 

Bird Conservation Region Strategies

Environment 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 either because of conservation concerns (i.e., those species vulnerable due to population size, distribution, population trend, abundance, or threats) or because of stewardship responsibilities (i.e., those species that typify the regional avifauna or have a large proportion of their range or population in the sub-region). Select any of the sub-regions below to view the BCR strategy for that region.

Listing of bird conservation regions, marine biogeographic units and sub-regions
Bird conservation region, marine biogeographic unitSub-region
Atlantic Northern ForestsAtlantic Northern Forests, sub-region: Atlantic Region - New Brunswick
Atlantic Northern ForestsAtlantic Northern Forests, sub-region: Atlantic Region - Nova Scotia
Atlantic Northern ForestsAtlantic Northern Forests, sub-region: Atlantic Region - Prince Edward Island
Atlantic Northern ForestsAtlantic Northern Forests, sub-region: Quebec Region
Boreal Hardwood TransitionBoreal Hardwood Transition, sub-region: Ontario Region
Boreal Hardwood TransitionBoreal Hardwood Transition, sub-region: Quebec Region
Boreal Softwood ShieldBoreal Softwood Shield, sub-region: Ontario Region
Boreal Softwood ShieldBoreal Softwood Shield, sub-region: Prairie and Northern Region
Boreal Softwood ShieldBoreal Softwood Shield, sub-region: Quebec Region
Boreal Taiga PlainsBoreal Taiga Plains, sub-region: Prairie and Northern Region
Lower Great Lakes/St. Lawrence PlainLower Great Lakes/St. Lawrence Plain, sub-region: Ontario Region
Lower Great Lakes/St. Lawrence PlainLower Great Lakes/St. Lawrence Plain, sub-region: Quebec Region
Taiga Shield and Hudson PlainsTaiga Shield and Hudson Plains, sub-region: Ontario Region
 

References