Prairie Warbler Habitat Model
go to: USFWS Gulf of Maine Watershed Habitat Analysis
go to: Species Table

Draft Date:
October, 2002

Species:
Prairie warbler, Dendroica discolor

Use of Study Area Resources:
Reproduction. The breeding range of the prairie warbler covers most of the eastern United States except for northern New England. The species extends westward to eastern Texas and Oklahoma..." (Nearctica). It winters "...almost exclusively on Caribbean Islands (Pashley and Martin 1988); common from the northern Bahamas through the Greater Antilles and the Cayman Islands; uncommon farther southeast to the central Lesser Antilles; also reported in central Florida and on islands of Caribbean coasts of Mexico and Central America (AOU 1983). " (Staicer 1995).

Habitat Requirements (Reproduction):
Cover:  "The prairie warbler (despite its name) is found in mixed pine-oak barrens (such as the New Jersey Pine Barrens), old pastures and fields, and dry hillsides. In the south the species is found in areas of scrub" (Nearctica).  Optimal breeding habitats are usually associated with poor soils and include brushy dune/lakeshore communities, fallow fields with scattered trees, young jack pine stands, pine plantations (especially Christmas tree plantings), oak clearcuts, and powerline right-of-ways (Evers 1994). Large openings surrounding or containing clumps of shrubs are typical components of breeding habitat. Populations typically exploit sites for short periods of time because preferred breeding habitat (early seral) coincides with rapid structural change in plant structure and composition (Evers 1994)" (from Cooper 2000).

"Brushy second growth, dry scrub, low pine-juniper, mangroves, pine barrens, burned-over areas, sproutlands... Subspecies DISCOLOR primarily inhabits various types of shrubby vegetation: brushy second growth, dry scrub, low pine-juniper, jack pine stands, pine barrens, coastal pine subclimax, christmas tree farms, burned-over or cut-over areas, sproutlands, grassland-forest ecotone, powerline corridors, inner forest of Great Dismal Swamp, corridors in hardwood swamps, revegetating strip-mined lands, overgrown apple orchards, and abandoned fields in the breeding season" (NatureServe).

Robbins et al. (1989) found that prairie warbler occurrences were positively associated with percent cover by conifers.

Avoids high elevations (DeGraaf and Rudis 1986); sea level to 1220 m elevation (Nolan, Jr. et al. 1999).

Area: Male territory size in Indiana, in early successional vegetation, ranged from 0.5 to 3.5 ha; for older vegetation sizes ranged from 0.4 to 2.4 ha. This corresponded with home range, during the breeding season (Nolan, Jr. et al. 1999).

"Two kinds of preserves are needed to accommodate breeding populations. For D. D. DISCOLOR, these include: (1) natural areas that have likely sustained populations for hundreds or thousands of years (the sand dunes along the Atlantic coast and parts of the Great Lakes, the Great Dismal Swamp, the grassland-forest ecotone; Nolan 1978); some of these naturally occur as narrow strips of vegetation, and (2) areas of subclimax pine forest, with shrub layer, maintained by regular burning; a shifting mosaic of seral stages would accommodate this and other species that require different stages of early successional pine habitats; optimal shape or distance between suitable patches is not known. " (Staicer 1995).

Foraging: "The diet of the prairie warbler consists of a variety of small invertebrates. Adults glean insects and spiders from vegetation and young are primarily fed caterpillars (Evers 1994)" (from Cooper 2000).

Model:
The Breeding Bird Atlas (BBA) data for Maine, New Hampshire and Massachusetts (courtesy of the University of Vermont COOP Unit) were used to identify the range of the prairie warbler within the study area.  BBA blocks and Breeding Bird Survey (BBS) sites in which prairie warblers were known to occur were used to select USDA Forest Service Ecological subunits (Keys et al. 1995); habitat mapping then was restricted to these areas.

Our land cover data do not distinguish forest succession stages, and the upland scrub/shrub cover is quite generalized.  In order to focus on woody barrens and regrowth, we mapped as prairie warbler habitat areas combining  1) 'open' land cover (grassland, bare ground), and 2) coniferous or mixed woody relatively dry land cover (upland coniferous, mixed, and shrub; see table, below). Habitat consisted of cells of both types, where the complementary type was immediately adjacent. The resulting map was filtered to eliminate areas above 1220 m in elevation or smaller than 1 ha.

NWI Designations (wetlands only)	Cover Types	Cover Suitability (0 - 1 scale)
	Upland deciduous forest
	Upland coniferous forest	1.0*
	Upland mixed forest	1.0*
	Grassland	1.0*
	Upland scrub/shrub	1.0*
	Cultivated
	Developed
	Bare ground	1.0*
PEM, L2EM	Lake/pond, emergent vegetation
PFOcon	Palustrine forest, conifer
PFOdec	Palustrine forest, deciduous
PSSdec	Palustrine scrub shrub, deciduous
PSScon	Palustrine scrub shrub, conifer
PAB, L2AB	Lake/pond, aquatic vegetation
L1UB, PUB	Lake/pond, unconsolidated bottom
L2US	Lake, unconsolidated shore
L2RS	Lake, rocky shore
R1UB	Riverine subtidal unconsolidated
Rper	Riverine perennial
E1AB	Estuarine subtidal vegetated
E1UB	Estuarine subtidal unconsolidated bottom
E2AB	Estuarine intertidal algae
E2EM	Estuarine intertidal emergent
E2RS, R1RS	Estuarine, tidal river rocky shore
E2SS	Estuarine intertidal shrub
E2US	Estuarine intertidal unconsolidated shore
M1AB	Marine subtidal vegetated
M1UB	Marine subtidal unconsolidated bottom
M2AB	Marine intertidal algae
M2RS	Marine intertidal rocky shore
M2US	Marine intertidal unconsolidated shore
NOTES	*if part of edge of grassland/bare and shrub/forest

Model testing: Prairie warbler warbler occurrences from 1990 and 1997 through 2000 along Breeding Bird Survey routes were used to test the habitat map from the above model. We compared the presence of habitat at these sites to that for a random set of 335 upland sites within the species range. All of the 23 sites with birds had mapped habitat, while 247 sites out of the 335 randomly distributed sites had habitat. Birds occurred in areas mapped as having habitat more frequently than would be expected by chance (Chi-square significant at < .005).

Sources:

Staicer, C.A., F.J. Dirrigl, Jr., G. Hammerson, and D.W. Mehlman. 1995. Species Management Abstract: Prairie warbler (Dendroica discolor). THE NATURE CONSERVANCY, 4245 North Fairfax Drive, Suite 100, Arlington, VA 2220; downloaded 10/01.

Cooper, J.L. 2000. Special animal abstract for Dendroica discolor (prairie warbler). Michigan Natural Features Inventory, Lansing, MI. 3 pp. At: www.dnr.state.mi.us/wildlife/heritage/mnfi/abstracts/zoology/ dendroica_discolor.pdf

DeGraaf, R.M. and D.D. Rudis. 1986. New England Wildlife: Habitat, Natural History and Distribution. USDA Technical Report NE-108.

Keys, J.E., Jr., J.C. Carpenter, S. Hooks, F. Koenig, W.H. McNab, W. Russell and W. Smith. 1995. Ecological units of the eastern United States - first approximation (map and booklet of map unit tables), USDA Forest Service. Atlanta, GA.

NatureServe: An online encyclopedia of life [web application]. 2001. Version 1.5 . Arlington, Virginia, USA: Association for Biodiversity Information. Available: http://www.natureserve.org/. (Accessed: November 20, 2001 ).

Nearctica. Warblers of Eastern North America. http://www.nearctica.com/birds/warbler/Ddisc.htm downloaded 10/01.

Nolan, Jr., V., E.D. Ketterson, and C.A. Buerkle. 1999. Prairie warbler, Dendroica discolor. In A. Poole and F. Gill, (eds.) The Birds of North America, No. 455. The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, D.C.

Robbins, C.R., 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.