[Fact box]

Landscape associations:

[BCR]

[Ecoprov.]

[BEC zones]

Print

Click on plot to view table of mean abundance

Characteristics and Range The Orange-crowned Warbler is a common breeder across North American's boreal and western forests. British Columbia is home to three of the four subspecies, which vary in their plumage, migratory routes, moult patterns, distribution and some ecological preferences. The grayest of the subspecies, O. c. celata, breeds across the Boreal Forest (including northern British Columbia) from the Alaskan to the Labrador coasts. The western interior O. c. orestera extends through the Northern Rockies and Great Basin Bird Conservation Regions, while O. c. lutescens, with the brightest yellow-green plumage, nests along the Pacific Coast. Highly migratory, Orange-crowned Warblers winter from the southern United States to Costa Rica (Gilbert et al. 2010). While they are primarily insectivorous, gleaning insects from leaves and blossoms, they also forage on berries, fruit, suet and feed at sap wells created by Red-naped Sapsuckers (Ehrlich and Daily 1988).

Distribution, Abundance, and Habitat The Orange-crowned Warbler is widely distributed throughout the province. Compared with The Birds of British Columbia published in 2001, the Atlas increased the number of breeding observations and confirmed breeding records in northern and central British Columbia, filling gaps within the known provincial distribution.

Unlike The Birds of British Columbia, which considers the Georgia Depression Ecoprovince to have the highest abundance, the Atlas Probability of Observation model and point count results indicate similarly high breeding abundance occurs throughout the Georgia Depression and parts of the Coast and Mountains ecoprovinces (especially Haida Gwaii), and the Sub-boreal Interior and western Northern Boreal Mountains ecoprovinces. The high numbers in the Georgia Depression are driven by very high abundance in the Coastal Douglas-fir biogeoclimatic zone.

The Orange-crowned Warbler reaches its highest abundance at low elevations below 250 m, primarily along the coast, and elevations between 750 and 1,250 m in the interior. It is found in a variety of forested habitats, usually associated with dense thickets or shrubs, especially riparian areas, shrubby coastal clear-cuts or transmission corridors, shrubby aspen stands or open mature stands with some deciduous trees and a mixed, native understory (Campbell et al. 2001).

Conservation and Recommendations While stable throughout much of Canada, Orange-crowned Warbler populations show long-term declines in British Columbia's Northern Pacific Rainforest and Great Basin Bird Conservation Regions (Environment Canada 2014). Similar declines are noted for Pacific Coast and western shrub-nesting populations of other species (NABCI-Canada 2012), and are likely due to coinciding and cumulative threats in these regions. Orange-crowned Warblers are flexible in habitat choice and can tolerate some extent of landscape fragmentation. However, western populations of this and other species are negatively impacted by loss and degradation of understory in coastal coniferous, oak woodland and southern interior riparian forests (Allombert et al. 2005, Gilbert et al. 2010), so forestry practices that promote understory growth, and policies that reduce understory browsing and trampling are strongly encouraged. Also, like many other passerines, Orange-crowned Warblers are potentially vulnerable to collisions with buildings and towers (e.g., Machtans et al. 2013), and nest predation.

Wendy E. Easton

Recommended citation: Easton, W.E. 2015. Orange-crowned Warbler in Davidson, P.J.A., R.J. Cannings, A.R. Couturier, D. Lepage, and C.M. Di Corrado (eds.). The Atlas of the Breeding Birds of British Columbia, 2008-2012. Bird Studies Canada. Delta, B.C. http://www.birdatlas.bc.ca/accounts/speciesaccount.jsp?sp=OCWA&lang=en [05 Oct 2024]