Whip-poor-will Habitat Model
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Whip-poor-will, Caprimulgus vociferus
Use of Study Area Resources:
Reproduction. Whip-poor-wills breed from north-central Saskatchewan east across southern Canada to Nova Scotia, south to Georgia west to northeastern Texas; also in the U.S. Southwest, south to Honduras (Brown et al. 1999, Veit and Petersen 1963). They winter along the Gulf Coast, and South Carolina south to Costa Rica, western Panama, and Cuba (Brown et al. 1999, Veit and Petersen 1963).
Cover: "Often found in riparian uplands, but this may not be a requirement for nesting habitat" (Brown et al. 1999). Whip-poor-will breeding habitat is usually in uplands, primarily deciduous and mixed forest adjacent to large clearings (Veit and Petersen 1963). They use open dry, predominantly deciduous woodlands (DeGraaf and Rudis 1983) "...with well spaced trees and a low canopy. Uncommon in mature forest; prefers even-aged successional habitats from regeneration to pole-stage stands" (Bushman and Therres 1988 in Brown et al. 1999). "Typical habitat includes a mix of forest and open areas such as fields, orchards, pastures, wetlands, or open water" (Robbins 1994). Lays eggs on the ground under trees or under bushes, at woods edge or in open woodland (DeGraaf and Rudis 1983, Brown et al. 1999).
Avoids mountains (DeGraaf and Rudis 1983); highest nesting observed in New Hampshire was 430 m (Robbins 1994).
Management: "Typically fly low to the ground and forage in and along roads... Grazing could have a detrimental effect on this and other ground nesting species" (Brown et al. 1999). There apparently has been a significant population decline in Massachusetts (Veit and Petersen 1963) and New Hampshire (Robbins 1994) since the 1960's.
Foraging: "Eats moths and other insects caught in flight usually near ground (Terres 1980). Makes short flights from perch or ground" (Brown et al. 1999). Occasionally eats crickets, ants, and beetles from the ground (DeGraaf and Rudis 1983).
Inspection of conditions at 5 Breeding Bird Survey sites in the study area revealed the presence of 'open' cover types with a minimum patch size of 12 ha, consisting variously of upland and wetland shrubs, marsh, grasslands, and blueberry fields. Coniferous, deciduous, and mixed forest all were present. This information was used to select the size of open areas and appropriate cover types for the habitat 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 whip-poor-will within the study area. BBA blocks were used to select USDA Forest Service Ecological subunits (Keys et al. 1995); habitat mapping then was restricted to these areas. All whip-poor-will occurrence information from the Breeding Bird Survey, from Robbins (1994), Veit and Petersen (1963), and Pierson et al. (1996) was found to coincide with this range.
Upland forest cover (see table, below) within 30 m of large openings (12 ha or larger in extent), and the margins (up to 30 m from the edge) of such large clearings adjacent to upland forest were regarded as whip-poor-will habitat. Areas above 450 m elevation were deleted from the final habitat grid.
|Cover Types||Cover Suitability
(0 - 1 scale)
|Upland deciduous forest||1.0*|
|Upland coniferous forest||1.0*|
|Upland mixed forest||1.0*|
|PEM, L2EM||Lake/pond, emergent vegetation||1.0**|
|PFOcon||Palustrine forest, conifer|
|PFOdec||Palustrine forest, deciduous|
|PSSdec||Palustrine scrub shrub, deciduous||1.0**|
|PSScon||Palustrine scrub shrub, conifer||1.0**|
|PAB, L2AB||Lake/pond, aquatic vegetation|
|L1UB, PUB||Lake/pond, unconsolidated bottom||1.0**|
|L2US||Lake, unconsolidated shore||1.0**|
|L2RS||Lake, rocky shore|
|R1UB||Riverine subtidal unconsolidated|
|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||*at elevations below 450 m and adjacent to open area > 12 ha
**at elevations below 450 m and adjacent to upland forest
Model testing: Because the Breeding Bird Survey occurrences were used in model development, they were not used to test the accuracy of the model (however, all 5 had mapped habitat). Other sites at which whip-poor-will occur, mentioned in Robbins (1994), Veit and Petersen (1963) and Pierson et al. (1996) were used to test the habitat map. We compared the presence of habitat near a random set of 742 upland points to that for sites at which whip-poor-will were observed. All of the 9 sites with birds had mapped habitat, while 399 out of the 742 randomly distributed sites had habitat. The occurrences were associated with habitat significantly more frequently than would be expected by chance (signif. at 0.0054), indicating that the model does predict areas of use to this bird.
DeGraaf, R.M. and D.D. Rudis. 1983. New England Wildlife: Habitat, Natural History and Distribution. USDA Technical Report NE-108.
Robbins, C.S. 1994. Whip-poor-will. In C.R. Foss (ed.) Atlas of Breeding Birds in New Hampshire. Audubon Soc. of New Hampshire, Concord, NH. 414 pp.
Brown, B.,M. Koenen and D.W. Mehlman. 1999. Species Management Abstract: Whip-poor-will (Caprimulgus vociferus). THE NATURE CONSERVANCY, 4245 North Fairfax Drive, Suite 100, Arlington, VA 2220; downloaded from http://www.conserveonline.org 2/02.
Pierson, E.C., J E. Pierson and P.D. Vickery. 1996. A Birders Guide to Maine. Down East Books, Camden, ME.
Veit, R.R. and W.R. Petersen. 1993. Birds of Massachusetts. Massachusetts Audubon Society. 514 p.