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Pileated Woodpecker
Dryocopus pileatus
Order
PICIFORMES
– Family
PICIDAE
Authors: Bull, Evelyn L., and Jerome A. Jackson
Revisors: Bull, Evelyn L., and Jerome A. Jackson

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Food Habits

Figure 3. Pileated Woodpecker feeding behavior.
Adult female Pileated Woodpecker head detail, Edmonton, AB, 17 April.

Feeding

Main Foods Taken

Insects, primarily carpenter ants (Camponotus spp.) and woodboring beetle larvae; also wild fruits and nuts.

Microhabitat For Foraging

W. U.S. and Canada. In ne. Oregon, 38% of foraging on logs, 38% on dead trees, 18% on live trees, and 6% on stumps; prefers Douglas-fir and western larch, avoids lodgepole pine (Pinus contorta), and uses ponderosa pine and grand fir in proportion to their availability (Bull and Holthausen 1993). Prefers logs ≥38 cm in diameter and extensively decayed. Carpenter ants, the primary prey of this woodpecker in ne. Oregon, select western larch logs >25 cm in diameter in a moderate stage of decay (Torgersen and Bull 1995.), so woodpecker preference of material probably reflects prey’s preference for habitat.

In w. Oregon, selects mature forests >70 yr old and avoids forests <40 yr old (Mellen 1987); forages in dead wood 96% of time; 44% in snags and 36% in down logs (Mannan 1984). East side of Cascades in w. Oregon, foraged primarily for carpenter ants in trees (78% of recent excavations in 221 trees accessed carpenter ant galleries) and wood-boring beetle larvae in logs (73% of excavations in 564 logs) (Raley and Aubry 2004). Compared to availability, selected larger diameter snags and logs for foraging and areas that had higher densities of potential foraging structures (Raley and Aubry 2005).

In closed canopy forests in w. Washington, foraged almost exclusively on standing structures (95%); selected tall, large diameter snags in early to moderate stages of decay; rarely foraged on logs (2%) which may be too wet and cool to support abundant populations of carpenter ants; favored foraging areas with high densities of large snags (> 52 cm dbh and > 7.5 m tall; Raley and Aubry 2006). Foraged primarily on carpenter ants (54% of diet) but wood-boring beetle larvae (Cerambycidae) and dampwood termites (Termopsidae) were important food items during the breeding season (Raley and Aubry 2006).

In se. Vancouver I., BC, foraging areas had greater basal areas of snags and defective trees, more coarse woody debris, and more western red cedar than areas not used; snags and defective trees used were larger, more decayed, and had less bark than those not used; logs used were larger, longer and less decayed than unused logs (Hartwig et al. (2006).

In Alberta, carpenter ants appeared to be the primary food source; adult woodpeckers selected for snags and large diameter substrates and selected against healthy live trees all year; selected injured or partly dead trees in winter; selected stubs and logs in summer; strong seasonal selection for tree species and decay class of dead substrates (Bonar 2001). Carpenter ant colonies were located by woodpeckers during the summer and fall, and birds returned repeatedly to the colonies over the winter to access a known and dependable food source. Bonar (2001) believes the reason Pileated Woodpeckers established and defended large territories in the Alberta foothill forests was to secure winter food resources, which appeared to be a limiting factor in that region.

E. U.S. and Canada. In Virginia, Pileateds preferred oak- hickory (Quercus-Carya) forest, mature stands with dense vegetation near ground, high basal area; 58% of foraging was on dead trees, 36% on live trees; trees used for foraging: 61% oaks, 19% conifers, and 20% mixture of others (Conner 1981). In Mississippi, foraged extensively on logs remaining in freshly burned areas (Schardien and Jackson 1978). Kilham (1976) reported foraging on dead pines, live oaks (Quercus virginiana), and rotting logs in Georgia and Florida.

Of 77 foraging substrates in nw. New Brunswick, 45% were in dying trees, 39% in dead trees, and 16% in living trees; 65% of substrates were deciduous and 35% coniferous. Dbh was the best predictor of substrate use, with preferences for deciduous substrates > 35 cm dbh, snags over live trees, and American beeches over other species (Lemaitre and Villard 2005). In s. New Brunswick, this species was associated with (and possibly depended on) older forests for foraging habitat; foraged on red spruce (Picea rubens), balsam fir (Abies balsamea), sugar maple (Acer saccharum), yellow birch (Betula alleghaniensis), trembling aspen (Populus tremuloides), and white birch (B. papyrifera); foraged on larger trees (mean dbh of 27 cm and 28 cm for coniferous and deciduous species, respectively) and more decayed trees than were randomly available (Flemming et al. 1999).

In Texas, foraged on live (68%) and dead (32%) trees in bottomland hardwood forests; foraged more on branches (70%) than on trunks (30%); appeared to be restrictive in its use of tree species (Conner et al.1994). In bottomland hardwood forests in Louisiana, live trees were used for foraging 83% of time, standing dead trees 14%, and coarse woody debris 3%; selected trees ≥ 50 cm dbh and avoided smaller trees; selected overcup oak (Quercus lyrata) and bitter pecan/water hickory (Carya aquatica); males and females foraged on similar tree species, decay classes, heights, and used similar foraging tactics, although males selected larger substrates than females (Newell et al. 2009).

In bottomland hardwood forests of Arkansas, dead trees (76%) were preferred over live trees (24%) based on 181 foraging substrates identified; foraged on shorter, larger (mean height =14.1 m; dbh = 59.4 cm), and more decayed trees than what were randomly available (mean height = 22.3 m; dbh = 47.5 cm, n = 363 trees); preferred sugarberry; 35%), water tupelo (22%), unknown trees (19%), and bald cypress (6%), although sugarberry (14%) and water tupelo (31%) were the most randomly available trees based on sampling (B.L. Noel pers. comm.).

Food Capture And Consumption

Primarily a subcambial excavator; also gleans on branches, trunks, and logs; pecks in bark; scales bark off trees. Large rectangular excavations in trees and logs are characteristic; can be >30 cm in length and so extensive as to cause tree to break. Pries off long slivers of wood to expose ant galleries. Occasionally forages on ground (R. Dixon pers. comm.).

Uses long, extensible, pointed tongue with barbs and sticky saliva to catch and extract ants from tunnels (Hoyt 1950). Gleans western spruce budworm (Choristoneura occidentalis) off grand fir and Douglas-fir branches. Perches on branches to secure cherries and berries (see Fig. 3).

Foraging strategy is known to change with the season in Virginia (Conner 1979): uses a combination of gleaning, pecking, scaling, excavating, and consuming of vegetable material during breeding and postbreeding periods; primarily excavating in winter. In ne. Oregon, foraging observations year-round: 53% excavating, 32% pecking, 10% gleaning, and 5% a combination (Bull and Holthausen 1993). In September in Oregon, adult male foraged on ponderosa pine cones and presumably ate the seeds (R. Dixon pers. comm.). In Louisiana, primarily winter: 77% excavating and 23% scaling (Tanner 1942). Radio-tagged males and females in 18 territories in Louisiana spent 58% of their time excavating, 14% pecking, 14% gleaning, 7% scaling, 4% berry-eating, and 3% probing; spent 54% of foraging time on live branches and boles, 37% on dead branches and boles, and 9% on vines in Louisiana (Newell et al. 2009). In Texas used the peer-and-poke method of foraging more than pecking, excavating, or scaling (Conner et al. 1994). Direct use of wings by foraging adults observed in the winter at logs with holes filled with purified beef fat in Indiana; wings used to prevent fat fragments from falling to the ground (Reynolds and Lima 1994).

Diet

Major Food Items

Ants and beetle larvae are taken all year, fruit and mast of wild nuts when available (Hoyt 1957). One observation of a female Pileated Woodpecker foraging on cartilage and muscle from a fresh beef bone in Missouri (Servin et al. 2001).

Quantitative Analysis

In ne. Oregon, diet determined from 330 scat samples consisted of: 68% carpenter ants, 29% thatching ants (Formica spp.), 0.4% beetles, and 2% other (included western spruce budworm, termites [Isoptera], and unknowns; Bull et al. 1992a). Diet changes seasonally, with thatching ants predominating from June through September, mostly absent in winter, and reoccurring in March; carpenter ants are in diet all year.

In w. Washington, based on 86 scat samples diet consisted of 54% carpenter ants (primarily Camponotus modoc), 25% round-headed wood-boring beetle larvae (Cerambycidae), 14% dampwood termites (probably Zootermopsis augusticollis), 3% other ants (Formica spp. and Lasius spp), other arthropods (mites (Acari), spiders (Araneae), flies (Diptera), true bugs (Hemiptera), and adult beetles; 4 scats contained seeds, some of which were either salal (Gaultheria shallon) or red huckleberry (Vaccinium parvifolium) (Raley and Aubry 2006). Diet composition varied by season with the highest percentage (71%) of carpenter ants taken during the non-breeding period (Nov-Feb) compared to 34% taken during the breeding period (Mar-Jun). More round-headed beetle larvae were taken during breeding, the juvenile-rearing, and dispersal periods (Jul-Oct) (Raley and Aubry 2006).

In New York, Hoyt (1948b) found seasonal shifts in primary food items: fruit in fall, carpenter ants in winter, wood-boring beetle larvae in early spring, and a variety of insects in summer.

In Pennsylvania this woodpecker is known to enlarge crevices in utility poles in order to extract overwintering paper wasps (Polistes sp.; Pfitzenmeyer 1956). Conner (1982) observed a female feeding on the large larvae of the horned passalus beetle (Popilius disjunctus) in Texas. Snyder (1948) found that 28 of 113 Pileated Woodpecker stomachs contained termites.

Analysis of 80 stomachs (Beal 1911): 22% beetles (Cerambycidae, Buprestidae, Elateridae, Lucanidae, Scarabaeidae, Carabidae), 40% ants (Camponotus pennsylvanicus, C. herculeanus, Cremastogaster laeviuscula), 11% other insects (flies, caterpillars, cockroaches, grasshoppers, sawflies, and others), 27% vegetable. Vegetable food: berries from greenbrier (Smilax glauca), cat brier (S. rotundifolia), laurel-leaved greenbrier (S. laurifolia), hackberry (Celtis occidentalis), sassafras (Sassafras sassafras), blackberry or raspberry (Rubus sp.), dwarf sumac (Rhus copallina), poison sumac (R. vernix), poison ivy (R. radicans), American holly (Ilex opaca), dahoon holly (I. cassine), frost grape (Vitis cordifolia), woodbine (Parthenocissus quinquefolia), flowering dogwood (Cornus florida), rough-leaved dogwood (C. asperifolia), black gum (Nyssa sylvatica), water tupelo, persimmon (Diospyros virginiana), fringe tree (Chionanthus virginica), elderberry (Sambucus canadensis), larger withe-rod (Viburnum nudum), and black haw (V. prunifolium).

Scat samples in Iowa consist primarily of carpenter ants (Downing 1940). In South Carolina, often seen eating magnolia (Magnolia grandiflora) seeds (Sprunt and Chamberlain 1970). In appropriate habitats, regularly patronizes suet feeders; Carter (1942) observed a male eating salmon which was bait to trap a cat.

Food Selection And Storage

Not known to store food. May find prey by sight (fruit on branch) or sound, particularly after pecking on wood which could increase ant activity or indicate hollow portion in tree or log.

Nutrition And Energetics

Little known, but captive birds fed 100 g of mealworms/d (Rumsey 1968).

Metabolism And Temperature Regulation

Little known. Roosting and nesting in cavities provide a thermoregulatory advantage as well as concealment from predators and protection from inclement weather.

Drinking, Pellet-Casting, And Defecation

Drinks from streams and ponds. Drinks at dusk on way to roost (Wetmore 1964). Usually defecates once per night outside roost cavity (ELB); defecates frequently during day at foraging sites.

Sounds Habitat