Distribution and Abundance
- BBS Map
- Breeding range across southern boreal region of Canada, southeast Canada,
northeastern United States, including Great Lakes region,
and south (at higher elevations) along the Appalachian Mountains to northeast
Georgia (Dunn and Garrett 1997).
- Probably disappeared from lower
peninsula of Michigan in late 1800s and early 1900s because of forest
clearing, but has reoccupied some of this area as isolated forest patches have
regenerated (Brewer et al. 1991).
- Less abundant compared to historical distribution due to land
cleared for farming in southwest Ontario (Cadman et al. 1987, Peck and James
1987). However, elimination of original pine forest and subsequent replacement
with mixed forest may
have allowed distribution to expand in southcentral Ontario.
- May be more widely distributed now compared to earlier this century in
New York and Vermont as forest cover has increased since that time (Laughlin
and Kibbe 1985, Andrle and Carroll 1988). Loss of suitable habitat owing to
development has slightly reduced distribution in eastern Pennsylvania (Brauning
- BBS data 1966-1996 indicate populations have declined 2.1% / year throughout
breeding range; declines particularly severe in northeast United States (Witham
and Hunter 1992, James et al. 1996).
- Winter range in South America, mostly in and east of Andes (Paynter 1995).
- Breeds in a wide range of deciduous and coniferous forests. Most abundant in
moist, mixed deciduous - coniferous forests with a well-developed understory.
Often near open water.
- In Wisconsin, of 277 observations from 1995-2000 where habitat was reported,
41.3% were in upland hardwood forest (particularly aspen) or upland mixed forest
(with pine or spruce),
34% were in lowland hardwood forest or lowland mixed forest, and
16.6% were in lowland hardwood shrub or lowland mixed shrub (WSO
2002). In Michigan, this species breeds most commonly in mesic deciduous forest,
wet mixed forest, and mesic mixed forest (Brewer et al. 1991).
- Common at higher elevations (hills and mountains), especially in southern
portion of range (Andrle and Carroll 1988, Brauning 1992). At lower elevations, often
restricted to cool, wet, low-lying areas including cedar woods, swampy forests,
sphagnum bogs, spruce-tamarack bogs, aspen and moist spruce-birch forests, and
alder and willow stands along stream banks (Clement and Gunn 1957, Peck and
James 1987, Andrle and Carroll 1988).
- Heterogeneous second-growth (early successional) mixed coniferous-deciduous
forests in northern Wisconsin (Sodhi and Paszkowski 1995). In Great Lakes/St.
Lawrence river valley, in Eastern hemlock-white pine-red pine forests that
have a maple-birch-American beech component (Clement and Gunn 1957).
- Nest site well-concealed, often in thickets or areas with dense ferns. In
wet, mossy areas within forest among ferns, stumps, and fallen logs. Dense
nest site cover appears to be important habitat requirement (Kendeigh 1945).
Nest typically on or near ground, often on slopes, knolls, in earthen banks,
or rocky areas (Peck and James 1987). Typically built within recessed hole of
upturned tree root mass, rotting tree stump or sphagnum moss hummock.
- During migration, found in shrubbery, bushes and vine tangles near edge of
parks, villages, and cities; also thickets of stream and woodland edges, swamps,
and willow trees; brushland, second-growth woodlands, and along edges of
timbered lowlands and watercourses.
- Winter habitat is dense undergrowth of submontane cloud and rain forests,
early to mid-secondary woodland growth, clearings, and shrubby forest edges;
also coffee plantations, hedgerows, and other semi-open areas.
- Considered socially monogamous; some evidence pair bond maintained
year-round. Mostly solitary or with mate during breeding season.
- During breeding season, both intraspecific and interspecific hostile
interactions observed (Morse 1970). Males defend territories by singing.
- When disturbed on nest, female often gives distraction display on ground.
- Observed in flocks and interacting with other species during migration.
- Observed in small groups within mixed-species flocks during winter.
Parasitism and Predation
- Considered to be fairly regularly parasitized by Brown-headed Cowbird in
suitable localities (Friedmann et al. 1977, Semenchuk 1992). Parasitized nests
reported in Canada, New York, Indiana, Michigan, and Minnesota (Friedmann
- However, in
Wisconsin, of 477 confirmed Brown-headed Cowbird observations from 1995-2000,
Canada Warbler was not indicated as a host species (WSO 2002).
- No information on kinds of predators.
Conservation and Management
- Several reported incidences of mortality due to collisions with television
towers and other human-made structures (Devitt 1967, Bohlen 1989, Weir 1989,
Ball et al. 1995).
- Considered sensitive to forest fragmentation (Enser 1992, Freemark and
Collins 1992). More abundant in nonthinned compared to thinned mature
stands of northeastern oak in central Massachusetts; may be
sensitive to deer browse. Densities of breeding Canada Warblers dropped
significantly as deer density increased from 8/sq mile
to 35/sq mile (DeGraaf et el. 1991).
Management practices aimed at reducing the broad-leafed component in forests
of Maritimes Provinces would likely have a negative effect if continued over
wide areas (Erskine 1992). Only 4 of 75 forest species surveyed showed a
stronger positive relationship between abundance and forest area. Probability
of occurrence in western Maryland and northwest West Virginia was greatest in
contiguous forests greater than 3,000 ha, reduced 50% in forests of 400 ha,
and occurrence 0% in forests less than 187 ha (Robbins et al. 1989).
- In contrast, occupies young, disturbed forest in northern Wisconsin (Sodhi
and Paszkowski 1995). Abundance highest in areas heavily logged 5-15 yr prior
in New York (Webb et al. 1977). Present in 10- and 20-yr-old clear-cuts and
selectively-cut areas but not in recent clear-cuts or uncut, mature forest
areas in West Virginia (Maurer et al. 1981). Common in hurricane-wrecked maple
swamps in New England (Clement and Gunn 1957) and in forested areas with
evidence of tree fall disturbance in British Columbia (Enns and Siddle 1996).
In West Virginia, abundance increased in years following storm-induced
blowdowns of canopy trees which created canopy openings but returned to
original numbers as the openings closed (Hall 1984).
- Canada Warbler is a species of Special Concern in both Indiana and Ohio.
Listed as Vulnerable in British Columbia and several areas with Canada Warbler
habitat have been proposed as protected areas (Cooper et al. 1997). Considered
a species in need of management and/or monitoring attention in southeastern US
(Hunter et al. 1993). Of 132 neotropical migrant species, tied for 7th for
species priorities for conservation needs (Smith et al. 1993).
- BBS trend results from 1966-2000 (Sauer et al. 2001) in the Northern Spruce-Hardwoods region indicate a
population decline of the Canada Warbler
in this region (-2.2, p=0.06 Trend
Graph S28), and a possible decline in the Great Lakes Transition region,
but more data are needed (-3.4, p=0.50 Trend
Graph S20). Survey-wide (US and Canada), this species has exhibited an overall decline
in population (-1.9, p=0.05 Trend
For more information about the conservation and management of the
Canada Warbler, please
see the Species
Management Abstract, from the Conserve
Online public library, maintained by The Nature Conservancy.
This species account is based on: Conway, C.J. 1999. Canada Warbler. In The Birds of North America, No.
421 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia,
PA, and The American Ornithologists' Union, Washington, DC.
- Andrle, R.F. and J.R. Carroll. 1988. The atlas of breeding birds in New York
state. Cornell University Press, Ithaca, NY.
- Ball, L.G., K. Zyskowski and G. Escalona-Segura. 1995. Recent bird mortality
at a Topeka television tower. Bull. Kans. Ornithol. Soc. 46:33-36.
- Brewer, R., G.A. McPeek and R.J. Adams, Jr. 1991. The atlas of breeding
birds of Michigan. Michigan State University Press, East Lansing, MI.
- Bohlen, H.D. 1989. The birds of Illinois. Indiana Univ. Press, Indianapolis,
- Brauning, D.W., ed. 1992. Atlas of breeding birds of Pennsylvania.
University of Pittsburgh Press, Pittsburgh, PA.
- Cadman, M.D., P.F.J. Eagles and F.M. Helleiner. 1987. Atlas of the breeding
birds of Ontario. University of Waterloo Press, Waterloo, ON.
- Clement, R.C. and W.W.H. Gunn. 1957. Canada Warbler. Pp. 238-338 in The
warblers of America (L. Griscom and A. Sprunt, Jr., eds.). Devin-Adair Co.,
- Cooper, J.M., K.A. Enns and M.G. Shepard. 1997. Status of the Canada warbler
in British Columbia. Wildlife Working report no. WR-81, Ministry of
Environment, Lands and Parks, Wildlife Branch, Victoria, B.C.
- DeGraaf, R.M., W.M. Healy and R.T. Brooks. 1991. Effects of thinning and
deer browsing on breeding birds in New England oak woodlands. For. Ecol.
- Devitt, O.E. 1967. The birds of Simcoe County, Ontario. Breveton Field Nat.
Club, Barrie, ON.
- Dunn, J.L. and K.L. Garrett. 1997. A field guide to warblers of North
America. Houghton Mifflin Co., New York.
- Enns, K.A. and C. siddle. 1996. The distribution, abundance, and habitat
requirements of selected passerine birds of the boreal and Taiga plains of
British Columbia. Wildlife Working Report no. WR-76, Ministry of
Environment, Lands and Parks, Wildlife Branch, Victoria, B.C.
- Enser, R.W. 1992. The atlas of breeding birds in Rhode Island. Rhode
Island Dept. of Environ. Manage., Providence, RI.
- Erskine, A.J. 1992. Atlas of breeding birds of the Maritimes Provinces.
Nimbus Publ. Limited and the Nova Scotia Museum, Nova Scotia.
- Freemark, K. and B. Collins. 1992. Landscape ecology of birds breeding in
temperate forest fragments. Pp. 443-454 in Ecology and conservation of
neotropical migrant landbirds (J.M. Hagan and D.W. Johnston, eds.). Smithson.
Inst. Press, Washington, D.C.
- Hall, G.A. 1984. Population decline of neotropical migrants in an
Appalachian forest. Am. Birds 38:14-18.
- Hunter, W.C., D.N. Pashley and R.E.F. Escano. 1993. Neotropical migratory
landbird species and their habitats of special concern within the southeast
region. Pp. 159-171 in Status and management of neotropical migratory birds
(D.M. Finch and P.W. Stangel, eds.). U.S. Dept. Agric., For. Serv. Gen.
Tech. Report RM-229, Rocky Mountain For. and Range Exp. Stn., Ft. Collins,
- James, F.C., C.E. McCulloch and D.A. Wiedenfeld. 1996. New approaches to
the analysis of population trends in land birds. Ecology 77:13-27.
- Kendeigh, S.C. 1945. Nesting behavior of wood-warblers. Wilson Bulletin
- Laughlin, S.B. and D.P. Kibbe, eds. 1985. The atlas of breeding birds
in Vermont. University Press of New England, Hanover, NH.
- Maurer, B.A., L.B. McArthur and R.C. Whitmore. 1981. Effects of logging on
guild structure of a forest bird community in West Virginia. Am. Birds
- Morse, D.H. 1970. Ecological aspects of some mixed species foraging flocks
of birds. Ecol. Monographs 40:119-168.
- Paynter, R.A. 1995. Nearctic passerine migrants in South America. Publ.
Nuttall Ornithol. Club, no. 25.
- Peck, G.K. and R.D. James. 1987. Breeding birds of Ontario: nidiology and
distribution. Vol. 2. Misc. Publ. Roy. Ont. Mus. Toronto.
- Robbins, C.S., D.K. Dawson and B.A. Dowell. 1989. Habitat area requirements
of breeding forest birds of the middle Atlantic states. Wildl. Monogr.
- Sauer, J.R., J.E. Hines and J. Fallon. 2001. The North American Breeding
Bird Survey, Results and Analysis 1966-2000. Version 2001.2, USGS
Patuxent Wildlife Research Center, Laurel, MD.
- Smith, C.R., D.M. Pence and R.J. O'Connor. 1993. Status of Neotropical
migratory birds in the Northeast: A preliminary assessment. Pp. 172-188 in
Status and management of neotropical migratory birds (D.M. Finch and P.W.
Stangel, eds.). U.S. Dept. Agric., For. Serv. Gen. Tech. Report RM-229, Rocky
Mountain For. and Range Exp. Stn., Ft. Collins, CO.
- Sodhi, N.S. and C.A. Paszkowski. 1995. Habitat use and foraging behavior of
four Parulid warblers in a second-growth forest. J. Field Ornithol.
- Webb, W.L., D.F. Behrend and B. Saisorn. 1977. Effect of logging on
songbird populations in a northern hardwood forest. Wildlife Monographs 55.
- Weir, R.D. 1989. Birds of the Kingston region. Quarry Press, Kingston,
- Wisconsin Society for Ornithology. 2002. Wisconsin
Breeding Bird Atlas.
- Witham, J.W. and M.L. Hunter, Jr. 1992. Population trends of neotropical
migrant landbirds in northern coastal New England. Pp. 85-95 in Ecology and
conservation of neotropical migrant landbirds (J.M. Hagan and D.W. Johnson,
eds.). Smithsonian Institution Press, Washington, D.C.