Northern Flicker Habitat Model
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Northern flicker, Colaptes auratus, for which five sub-species have been identified. The common or yellow-shafted flicker, Colaptes auratus auratus is described here (Moore 1995).
Use of Study Area Resources:
Reproduction, wintering. Northern flickers breed from Labrador west to Alaska, and south to Central America (DeGraaf and Rudis 1986, Moore 1995). They winter as far north as central New England and west to South Dakota. Flickers breed throughout the study area and winter in southeastern Massachusetts.
Cover. Flickers are ground-foraging woodpeckers that nest in tree cavities (Moore 1995). They prefer forest edges and open woodlands, and are found in forested wetlands, river corridors, beaver impoundments with numerous snags, farms, orchards, shelter belts, hedgerows, suburban yards and urban parks (Moore 1995, Terres 1995). The structural aspects of the forest are more important for nesting than the tree species composition (Conner et al. 1975 in Moore 1995). Nesting habitat is most often characterized by mature or dead and dying trees, a high canopy, and access to open ground for foraging (Conner and Adkisson 1977, Swallow et al. 1988).
Foods. Flickers typically forage on the ground, in open areas, for ants which make up nearly half of their diet; beetles, wasps, grasshoppers, flies, caterpillars and grubs bring the animal portion of their diet to 75%. The remaining 25% consists of berries, fruits and seeds (Terres 1995).
Availability of nest cavities appears to limit flicker population density. Northern flickers may compete for snag trees with other species (Moore 1995). Forest area was not found to be correlated with flicker occurrences (Robbins et al. 1989). Although common, this species is declining, possibly due to loss of habitats that are open and near suitable nesting cavities, and possibly due to insecticide use on suburban lawns.
Because northern flickers require large dead/dying snag trees for nesting and low-growth cover for feeding, the model selects areas where forest and fields are in close proximity (within 30 m of each other). The cover types used in the analysis are shown in the following table.
|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|
|PFOcon||Palustrine forest, conifer||1.0*|
|PFOdec||Palustrine forest, deciduous||1.0*|
|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|
|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||*edge of forested
Model testing: The northern flicker occurrences along Breeding Bird Survey routes throughout the study area were used to test the habitat map. We compared the distribution of flicker habitat around a random set of 797 upland points to that for Breeding Bird Survey stops at which northern flickers were observed in 1990, 1997, or 1998. Of the 402 sites with birds, 395 had mapped habitat, while 687 sites out of the 797 randomly distributed sites had habitat. The Chi-square was highly significant, indicating that the overall model does indicate localities useful for flickers.
Conner, R.N. and C.S. Adkisson. 1977. Principal component analysis of woodpecker
nesting habitat. Wilson Bull. 89(1):122-129.
DeGraaf, R.M. and D.D. Rudis. 1986. New England Wildlife: habitat, natural history, and distribution. Gen. Tech. Rep. NE-108. Broomall, PA, USDA/USFS. 491p.
Moore, W.S. 1995. Northern flicker, Colaptes auratus. In A. Poole and F. Gill, (eds.) The Birds of North America, No. 166. The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, D.C.
Robbins, C.S., D.K. Dawson and B.A. Dowell. 1989. Habitat area requirements of breeding forest birds of the middle Atlantic states. Wildl. Monograph 103. The Wildl. Soc. 34 pp.
Swallow, S.K., R.A. Howard, Jr. and R.J. Gutierrez 1988. Snag preference of woodpeckers foraging in a northeastern hardwood forest. Wilson Bull. 100(2):236-246.
Terres, J.K. 1995. The Audubon Society Encyclopedia of North American Birds. Wings Books, Avenel, NJ. 468 p.