Northern Parula

Distribution and Abundance

• BBS Map
• Breeding range eastern United States and eastern southern Canada; although absent in a gap ranging from southern Minnesota and northern Iowa eastward to portions of New England.
• Largely extirpated or reduced in numbers in southern Michigan (Brewer et al. 1991), southern Wisconsin (Robbins 1991), and the Mississippi lowlands of Missouri (Robbins and Easterla 1992) and in several northeast states including Massachusetts (Forbush 1929), Connecticut (Zeranski and Baptist 1990), New Jersey (Sibley 1993), New York (Peterson 1988), Rhode Island (Enser 1992), and Vermont (Kibbe 1985).
• Disappeared from several northeastern counties in Ohio, but by 1958 had expanded into southwest Ohio where it nested for the first time in the Cincinnati area (Peterjohn and Rice 1991). Prior to 1952, no records in California; since then, this species has nested several times along coastal areas (Yee et al. 1993).
• Densities range widely with habitat and geographic location. BBS data indicate that in the western part of this species' range, populations declined significantly from 1966 to 1988; eastern populations declined from 1978-1988. No significant increases over the long term (Sauer and Droege 1992), although increases have occurred in the Mississippi alluvial plain and lower coastal plain (James et al. 1992). From 1986-1992, in Wisconsin, mean number of individuals increased, whereas in the Upper Peninsula of Michigan, there was a slight decrease (Blake et al. 1994).
• Winters in the Caribbean, Bermuda, parts of southern Mexico and parts of Central America.

Habitat

• Primarily a riparian species; usually associated with mature forest with epiphytic growth. In northern part of range, prefers tall, mature coniferous forests with spruce, hemlock, and fir in moist bog and swamp habitat where beard moss is abundant.
• In Wisconsin, 37.5% of 232 observations from 1995-2000 were in upland mixed forest, 21% in lowland conifer forest, and 13% in lowland mixed forest (WSO 2002). In Michigan, this species predominately breeds in northern coniferous forests, although will also use northern hardwood forest, mesic mixed forest, and wet coniferous areas (Brewer et al. 1991). Along the northern shore of Lake Huron in Michigan's Upper Peninsula, this species occurs exclusively right along the shoreline where it nests in beard lichens (Hamas, personal communication).
• In Illinois, population densities consistently higher in bottomland forest than in upland forest (Graber et al. 1983). In north-central Minnesota, inhabits primarily mature, undisturbed mixed forest of predominately deciduous trees with moderate ground and shrub cover and greater than 75% canopy cover (Collins et al. 1982). 
• In Nova Scotia, prefers hardwood stands of sugar maple, red maple, paper birch, and yellow birch; most abundant in 40-yr-old stands of trees, less numerous in younger and older-aged stands; density positively correlated with tree density, basal area, percent of canopy cover, and canopy height (Morgan and Freedman 1986).
• During breeding season in areas where there is a mixture of coniferous and deciduous trees, this species prefers to forage in coniferous rather than deciduous trees; foraging areas expand after young hatch to include nearby deciduous growth (Morse 1967).
• Nest usually hidden in hanging tendrils of epiphytic growth, either beard moss or lace lichen in the north (Spanish moss in the south). Preferred nesting sites are usually near water; e.g., river bottoms, sloughs, swamps. Nests tend to be located at the end of a branch, anywhere from 2-30 m above ground. Less common non-epiphytic nests reported in areas where epiphytic growth is rare or absent (Hall 1983).
• During spring migration, habitat selection similar to that of breeding season (Bairlien 1992), although during fall migration in Wisconsin, found in any tree or shrub (Robbins 1991).
• This species is a habitat generalist on winter grounds, occurring with nearly equal frequencies in most common habitat types available (Arendt et al. 1992, Robbins et al. 1992).

Behavior

• Diet mostly insects and spiders; in suboptimal habitat in winter will also feed on berries, seeds and nectar.
• Generally monogomous. Males defend established territories with singing and chasing during the breeding season. Relatively nonsocial on breeding grounds. Intraspecific physical interactions more common than interspecific interactions, although interactions with other warblers reported (Morse 1967, Wunderle 1978, Burtt 1986, Stacier 1992).
• Territory sizes range from 0.30-0.51 ha in Maine (Morse 1977); 0.08-0.65 ha in Nova Scotia.
• Forms mixed flocks with other paruline species on wintering grounds and during migration (Post 1978, Ewert and Askins 1991, Stacier 1992).

Parasitism and Predation

• Few but widespread records of Brown-headed Cowbird parasitism. Owing to the closed structure of its nest, Northern Parula is probably an uncommon cowbird host. Reported to build over nests containing cowbird eggs (Schwilling 1951), although adults feeding cowbird fledglings have been observed. In Wisconsin, of 477 confirmed Brown-headed Cowbird observations from 1995-2000, Northern Parula was not indicated as a host species (WSO 2002).
• No specific predators reported, but red squirrels and Blue Jays are probable nest predators. Snakes may feed on eggs, young, and adults (Stevenson and Anderson 1994). Adults likely preyed on by small hawks and owls. Injury feigning (Graber and Graber 1951) and distraction displays (Peterjohn and Rice 1991) observed.

Conservation and Management

• Has been extirpated as a nesting species in several northeast states where increasing air pollution has adversely affected the growth of the epiphytes the birds use for nesting.
• Clearcutting of forest habitat has negatively affected the species in southern Michigan (Brewer et al. 1991), southern Wisconsin (Robbins 1991), and the Mississippi lowlands of Missouri (Robbins and Easterla 1992).
• Northern Parula may be an area-sensitive species as it is uncommon in small forests (Freemark and Collins 1991). In middle Atlantic states, forest area was a significant predictor of relative abundance; rarely encountered in forests of less than 100 ha (Robbins et al. 1989).
• Draining of bogs and other moist habitats has been implicated in population declines in southern Wisconsin (Robbins 1991) and New York (Bull 1974).
• Population decline in the Maritime Provinces prior to 1966 attributed to widespread use of DDT in New Brunswick from 1952-1967 to combat spruce budworm outbreaks (Erskine 1992).
• Hundreds of birds killed annually during migration after collisions with TV towers and other tall human-made structures (Bull 1974, Ralph 1981, Graber et al. 1983, Robbins 1991, Robbins and Easterla 1992, Stevenson and Anderson 1994).
• BBS trend results from 1966-2000 (Sauer et al. 2001) in the Northern Spruce-Hardwoods region indicate a significant population increase of the Northern Parula in this region  (2.1, p=0.00 Trend Graph S28); in the Great Lakes Transition region, this species may be experiencing an increase, but more data are needed (1.9, p=0.71 Trend Graph S20). Survey-wide (US and Canada), this species has overall shown a slight but significant increase (0.9, p=0.02 Trend Graph SUR).

For more information about the conservation and management of the Black-and-white Warbler, please see the Species Management Abstract, from the Conserve Online public library, maintained by The Nature Conservancy.

References

• Arendt, W.J., with collaborators. 1992. Status of North American migrant landbirds in the Caribbean region: a summary. Pp. 143-171 in Ecology and conservation of neotropical migrant landbirds (J.M Hagen III and D.W. Johnston, eds.). Smithson. Inst. Press, Washington, D.C.
• Bairlien, F. 1992. Morphology-habitat relationships in migrating songbirds. Pp. 356-369 in Ecology and conservation of neotropical migrant landbirds (J.M Hagen III and D.W. Johnston, eds.). Smithson. Inst. Press, Washington, D.C.
• Blake, J.G., J.M. Hanowski, G.J. Niemi and P.T. Collins. 1994. Annual variation in bird populations of mixed conifer-northern hardwood forests. Condor 96:381-399.
• Brewer, R., G.A. McPeek and R.J. Adams. 1991. The breeding birds of Michigan. Michigan State University Press, East Lansing.
• Bull, J. 1974. Birds of New York State. Cornell University Press, Ithaca, NY.
• Burtt, E.H. 1986. An analysis of physical, physiological, and optical aspects of avian coloration with emphasis on wood-warblers. Ornithol. Monogr. 38.
• Collins, S.L., F.C. James and P.G. Risser. 1982. Habitat relationships of wood warblers in northern central Minnesota. Oikos 39:50-58.
• Enser, R.W. 1992. The atlas of breeding birds in Rhode Island. Rhode Island Dept. Environ. Manage.
• Erskine, A.J. 1992. Atlas of breeding birds of the Maritime Provinces. Nimbus/Nova Scotia Mus., Halifax.
• Ewert, D.N. and R.A. Askins. 1991. Flocking behavior of migratory warblers in winter in the Virgin Islands. Condor 93:864-868.
• Forbush, E.H. 1929. Birds of Massachusetts and other New England states. Pt. 3. Commonwealth of Massachusetts.
• 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 Hagen III and D.W. Johnston, eds.). Smithson. Inst. Press, Washington, D.C.
• Graber, R. and J. Graber. 1951. Nesting of the Parula Warbler in Michigan. Wilson Bull. 63:75-83.
• Graber, R.R., J.W. Graber and E.L. Kirk. 1983. Illinois birds: wood warblers. Ill. Nat. Hist. Surv. Biol. Notes no. 118.
• Hall, G.A. 1983. West Virginia birds. Carnegie Mus. Nat. Hist. Spec. Publ. 7.
• James, F.C., D.A. Wiedenfeld and C.E. McCulloch. 1992. Trends in breeding populations of warblers: declines in the southern highlands and increases in the lowlands. Pp. 43-56 in Ecology and conservation of neotropical migrant landbirds (J.M Hagen III and D.W. Johnston, eds.). Smithson. Inst. Press, Washington, D.C.
• Hamas, Michael. Personal Communication.
• Kibbe, D.P. 1985. Northern Parula. Pp. 282-283 in The atlas of breeding birds of Vermont (S.B. Laughlin and D.P. Kibbe, eds.). University Press of New England, Hanover, NH.
• Morgan, K. and B. Freedman. 1986. Breeding bird communities in a hardwood forest succession in Nova Scotia. Can. Field-Nat. 100:506-519.
• Morse, D.H. 1967. Competitive relationships between Parula Warblers and other species during the breeding season. Auk 84:490-502.
• Morse, D.H. 1977. The occupation of small islands by passerine birds. Condor 79:399-412.
• Peterjohn, B.G. and D.L. Rice. 1991. The Ohio breeding bird atlas. Ohio Dep. Nat. Resources, Columbus.
• Peterson, J.M.C. 1988. Northern Parula. Pp. 366-367 in The atlas of breeding birds in New York state (R.F. Andrle and J.R. Carroll, eds.). Cornell Univ. Press, Ithaca, NY.
• Post, W. 1978. Social and foraging behavior of warblers wintering in Puerto Rican coastal scrub. Wilson Bull. 90:197-214.
• Ralph, C.J. 1981. Age ratios and their possible use in determining autumn routes of passerine migrants. Wilson Bull. 93:164-188.
• 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. 103:1-34.
• Robbins, C.S., B.A. Dowell, D.K. Dawson, J.A. Colón, R. Estrada, A. Sutton, R. Sutton and D. Weyer. 1992. Comparison of neotropical migrant landbird populations wintering in tropical forest, isolated fragments, and agricultural habitats. Pp. 207-210 in Ecology and conservation of neotropical migrant landbirds (J.M Hagen III and D.W. Johnston, eds.). Smithson. Inst. Press, Washington, D.C.
• Robbins, M.B. and D.A. Easterla. 1992. Birds of Missouri. University of Missouri Press, Columbia.
• Robbins, S.D., Jr. 1991. Wisconsin birdlife. University of Wisconsin Press, Madison.
• Sauer, J.R. and S. Droege. 1992. Geographic patterns in population trends of neotropical migrants in North America. Pp. 26-42 in Ecology and conservation of neotropical migrant landbirds (J.M Hagen III and D.W. Johnston, eds.). Smithson. Inst. Press, Washington, D.C.
• 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.
• Schwilling, M.D. 1951. Parula Warbler nesting in Kansas. Condor 53:100-101.
• Sibley, D. 1993. The birds of Cape May. Cape May Bird Observ., Cape May, NJ.
• Stacier, C.A. 1992. Social behavior of the Northern Parula, Cape May Warbler, and Prairie Warbler wintering in second-growth forest in southwestern Puerto Rico. Pp. 308-328 in Ecology and conservation of neotropical migrant landbirds (J.M Hagen III and D.W. Johnston, eds.). Smithson. Inst. Press, Washington, D.C.
• Stevenson, H.M. and B.H. Anderson. 1994. The birdlife of Florida. University Press of Florida, Gainseville.
• Wisconsin Society for Ornithology. 2002. Wisconsin Breeding Bird Atlas.
• Wunderle, J.M. 1978. Territorial defense of a nectar source by a Palm Warbler. Wilson Bull. 90:297-299.
• Yee, D.G., S.F. Bailey and B.E. Deuel. 1993. Middle Pacific coast region. Am. Birds 47:1147-1148.
• Zeranski, J.D. and T.R. Baptist. 1990. Connecticut birds. University Press of New England, Hanover, NH.