Status of Birds in Canada
One of the rarest songbirds in North America with a breeding range highly fragmented and restricted to northeastern North America. Bicknell's Thrush was recognized as a distinct species in 1995, when it was taxonomically separated from the Gray-cheeked Thrush. Species-specific surveys since the early 1990s indicate a steady decrease through most of the range in both the United States and Canada. Although data are imprecise, the Breeding Bird Survey results suggest a decrease since about 1970. Current threats to the population are high, and include habitat loss, climate change, squirrel predation and environmental contaminants (COSEWIC 2010b, Rimmer et al. 2001). The species is listed as one of the highest bird conservation priorities in North America. It was listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as Special Concern in 1999 but revised to Threatened in 2009 (COSEWIC 2010b).
Bicknell's Thrush presents a significant challenge to wildlife managers, researchers and conservation organizations. It is secretive and occupies remote and inhospitable habitats which make design, implementation and interpretation of field surveys difficult. It winters exclusively in the Greater Antilles, primarily in the Dominican Republic, with lesser numbers in Haiti and eastern Cuba where habitat loss has been substantial and is thought to be a significant limiting factor (McFarland et al. 2008). Further threats come from habitat modification due to climate change (McFarland et al. 2008), and high moose populations in parts of its range, red squirrel predation (COSEWIC 2010b), habitat loss and fragmentation (McFarland et al. 2008), and contaminants in high elevation habitats (McFarland et al. 2008). A further challenge occurs in the Maritime Provinces where parts of the breeding population overlap with forest management activities, which can have both beneficial (through the creation of vigorous, dense new coniferous growth after logging) and harmful (through pre-commercial thinning) effects on breeding habitat. Conservation efforts should focus on wintering habitat preservation and limiting detrimental activities on the breeding grounds, such as forest thinning and commercial and recreational developments in prime habitat, that further degrade habitat. Research on direct causes of population decreases should be carried out and long-term monitoring should be continued and expanded to all areas of the breeding range, especially Québec where little is known of the population. The second Maritimes Breeding Bird Atlas, scheduled for completion in 2010, and the second Atlas of the Breeding Birds of Québec, scheduled to begin in 2010, will provide valuable information on distribution and occupancy change in the 20-year period between atlases. For information on the legal status of this species under the Species at Risk Act (SARA) see the SARA Registry.
Information on this and other species has been compiled by ecoregion through the Bird Conservation planning process. For more details, click Bird Conservation Plans.