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Home , Acorn woodpecker, Hairy woodpecker, Nest box, Woodpecker

Rex E. Marsh Specialist in Vertebrate Ecology (retired) Department of Wildlife, Fisheries, and Conservation Biology University of Davis, California 95616

Fig. 1. Red-headed , erythrocephalus (left); , pubescens (right).

Identification Damage Prevention and Toxicants Control Methods None are registered. Woodpeckers belong to the Trapping and the Picidae, Exclusion which also includes flickers and sap- Rat snap trap. Netting. suckers. Twenty-one inhabit Shooting the . Woodpeckers have Metal barriers. short legs with two sharp-clawed, Effective where shooting can be con- Frightening backward-pointed toes and stiff tail ducted safely. Permits are required. feathers, which serve as a supportive Visual. Other Methods prop. These physical traits enable them Sound. to cling easily to the trunks and Suet as alternative food. branches of trees, siding, or util- Repellents boxes as alternative cavities. ity poles while pecking. They have Olfactory. stout, sharply pointed for peck- Insecticides for indirect control. ing into wood and a specially devel- Taste. oped long tongue that can be extended Tactile. a considerable distance. The tongue is used to dislodge larvae or ants from their burrows in wood or bark.

PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994 Cooperative Extension Division Institute of Agriculture and Natural Resources University of Nebraska - Lincoln United States Department of Agriculture and Plant Health Inspection Service Animal Damage Control E-139 Great Plains Agricultural Council Wildlife Committee Woodpeckers are 7 to 15 inches (18 to General Biology, in certain seasons, occasionally be seen 38 cm) in length, and usually have Reproduction, and in flocks of several hundred. brightly contrasting coloration. Most males have some red on the head, and Behavior Damage and Damage many species have black and white Woodpeckers are an interesting and Identification marks. Identification of species by familiar group of . Their ability to their markings is quite easy. In most peck into trees in search of food or Woodpecker damage to buildings is a species, flight is usually undulating, excavate nest cavities is well known. relatively infrequent problem nation- with wings folded against the body They prefer snags or partially dead wide, but may be significant regionally after each burst of flaps. trees for nesting sites, and readily peck and locally. Houses or buildings with holes in trees and wood structures in wood exteriors in suburbs near Range search of beneath the surface. wooded areas or in rural wooded set- One common misconception is that tings are most apt to suffer pecking Woodpeckers are found throughout they peck holes in buildings only in and hole damage. Generally, damage the United States. The three most search of insects. While they do obtain to a building involves only one or two widely distributed species are the insects by this means, many species birds, but it may involve up to six or (Picoides villosus), will holes in sound dry wood of eight during a season. Most of the the downy woodpecker (P. pubescens, buildings, utility poles, and posts damage occurs from February through Fig. 1), and the yellow-bellied sap- where few or no insects exist. The June, which corresponds with the sucker (Sphyrapicus varius). Different (Melanerpes for- breeding season and the period of ter- species are responsible for damage in micivorus) holes in wood simply ritory establishment. different regions. to store acorns. When drill their numerous rows of 1/4-inch (0.6- The following species of woodpeckers cm) holes in healthy trees they are pri- are most generally involved in damag- marily after sap and the insects ing homes or other wooden, human- entrapped by the sap. made structures: Because they are dependent on trees Common name Scientific name Woodpeckers have characteristic calls, for shelter and food, woodpeckers are but they also use a rhythmic pecking Red-headed Melanerpes erythrocephalus found mostly in or on the edge of sequence to make their presence Acorn Melanerpes formicivorus wooded areas. They nest in cavities Golden-fronted Melanerpes aurifrons known. Referred to as “drumming,” it chiseled into tree trunks, branches, or Red-bellied Melanerpes carolinus establishes their territories and appar- Ladder-backed Picoides scalaris structures, or use natural or preexist- ently attracts or signals mates. Drum- Downy Picoides pubescens ing cavities. Many species nest in ming is generally done on resonant Hairy Picoides villosus human-made structures, and have Red-cockaded Picoides borealis dead tree trunks or limbs; however, thus extended their habitat to include auratus buildings and utility poles may also be Pileated pileatus wooden fence posts, utility poles, and used. buildings. Because of this, woodpeck- Woodpeckers can be particularly de- ers may be found in localities where Woodpeckers breed in the spring, structive to summer or vacation homes trees are scarce in the immediate commonly laying in the range of 3 to 5 that are vacant during part of the year, vicinity. or 4 to 6 eggs. The incubation period is since their attacks often go undetected generally short, lasting from 11 to 14 until serious damage has occurred. For Food Habits days. It may be longer for larger spe- the same reason, barns and other cies. Most species are born naked; wooden outbuildings may also suffer some are born downy. All are tended severe damage. Most woodpeckers feed on tree-living by both parents. Having 2 broods per or wood-boring insects; however, year is fairly common and some spe- Damage to wooden buildings may some feed on a variety of other insects. cies may have 3 broods. Apparently, take one of several forms. Holes may Some flickers obtain the majority of both sexes sleep in cavities throughout be drilled into wood siding, eaves, their food by feeding on insects from the year. window frames, and trim boards. the ground, especially ants. Others Woodpeckers prefer cedar and red- feed primarily on vegetable matter, Some species, such as the northern wood siding, but will damage , , such as native berries, fruit, nuts, and flicker (Colaptes auratus) and the red- cypress, and others when the choices certain seeds. In some areas, the diet headed woodpecker (Melanerpes are limited. Natural or stained wood includes cultivated fruit and nuts. The erythrocephalus, Fig. 1), are migratory, surfaces are preferred over painted sapsuckers, as the name suggests, feed but most live year-round in the same wood, and newer houses in an area are extensively on tree sap as well as area. Most species live in small social often primary targets. Particularly vul- insects. groups; a few, such as the Lewis’ nerable to damage are rustic-appear- woodpecker (Melanerpes lewis), may, ing, channeled (grooved to simulate

E-140 reverse board and batten) and metal roof valleys. Drumming with cedar or redwood veneers. may occur a number of times during a Imperfections (core gaps) in the single day, and the activity may go on intercore layers exposed by for some days or months. Wood sur- the vertical grooves may harbor faces may be disfigured from drum- insects. The woodpeckers often break ming but the damage may not be out these core gaps, leaving character- severe. istic narrow horizontal damage pat- Sapsuckers bore a series of parallel terns in their search for insects. rows of 1/4- to 3/8-inch (0.6- to 1.0- If a suitable cavity results from wood- cm) closely spaced holes in the bark of pecker activities, it may also be used limbs or trunks of healthy trees and for roosting or nesting. use their tongues to remove the sap (Fig. 2). The birds usually feed on a The acorn woodpecker, found in the few favorite ornamental or fruit trees. West and Southwest, is responsible for Nearby trees of the same species may drilling closely spaced holes just large be untouched. Holes may be enlarged enough to accommodate one acorn through continued pecking or limb each. Wedging acorns between or growth, and large patches of bark may beneath roof shakes and filling be removed or sloughed off. At times, unscreened rooftop plumbing vents limb and trunk girdling may kill the with acorns are also common tree. activities. On trees, the wounds of Relatively new damage problems are attacked trees may attract insects as arising where damage-susceptible well as porcupines or tree squirrels. materials such as plastic are used for Feeding wounds also serve as rooftop water-heating solar panels or entrances for diseases and wood- where electrical solar panels are used. decaying organisms. Wood-staining Woodpeckers have also reportedly fungi and bacteria may also enter the damaged elevated plastic irrigation wounds, reducing the quality of the lines in several vineyards in California. wood when cut. Woodpecker damage Fig. 2. Yellow-bellied , Sphyrapicus Widespread damage from nest cavities to trees can be costly. varius and acorn holes in utility poles in some Wounds cause a grade defect called regions has necessitated frequent and “ peck” that lowers the value of where the Lewis’ woodpecker costly replacement of weakened poles. . Damage occurs to both (Melanerpes lewis), whose flocks may Similar damage to wooden fence posts commercial hardwoods and soft- number several hundred, is most often can also be a serious problem for some . Certain tree species are pre- implicated. farmers and ranchers. Occasionally, ferred over others, but the list of woodpeckers learn that beehives offer susceptible trees is extensive. an extraordinary food resource and Legal Status As mentioned previously, vegetable drill into them. matter makes up a good portion of the Woodpeckers are classified as migra- Drumming, the term given to the food of some woodpeckers, and native tory, nongame birds and are protected sound of pecking in rapid rhythmic fruits and nuts play an important role by the Federal Migratory Bird Treaty succession on metal or wood, causes in their diet. Cultivated fruits and nuts Act. The red-cockaded woodpecker little damage other than possible may also be consumed. Birds involved (Picoides borealis) and the ivory-billed removal on metal surfaces; however, in orchard depredation are often so woodpecker ( principalis) the noise can often be heard through- few in number that damage is limited are on the Endangered Species list and out the house and becomes quite an- to only a small percentage of the crop. are thus offered full protection. When noying, especially in the early morning The crop of a couple of isolated back- warranted, woodpeckers other than hours when occupants are still asleep. yard fruit or nut trees may, however, the endangered species can be killed Drumming is predominantly a spring- be severely reduced prior to harvest. but only under a permit issued by the time activity. Drumming substrates In recent times, controls against wood- Law Enforcement Division of the US are apparently selected on the basis of peckers to protect commercial crops Fish and Wildlife Service upon recom- the resonant qualities. They often have only rarely been necessary. Pub- mendation of USDA-APHIS-Animal include metal surfaces such as metal lished accounts suggest that these iso- Damage Control personnel. Generally, gutters, downspouts, chimney caps, lated instances occurred mostly in the there must be a good case to justify is- TV antennas, rooftop plumbing vents, fruit-growing states of the far West suance of a permit.

E-141 Some of the harder compressed wood or wood-fiber siding materials cannot be damaged by woodpeckers. Presum- ably, their hardness and/or smooth surface serve as deterrents. Aluminum siding can also be used as an alterna- tive to wood siding. To protect trees from sapsuckers, wrap barriers of 1/4-inch (0.6-cm) hardware cloth, plastic mesh, or burlap around injured areas to discourage further damage. This method may be practical for protecting high-value ornamental or shade trees. In orchards and forested areas it may be best to let the Fig. 3. Plastic netting attached to a building from the outside edge of the eave and angled back to the sapsuckers work on one or more of wood siding. Insert shows one method of attachment using hooks and wooden dowels. their favorite trees. Discouraging them from select trees may encourage the Woodpeckers are commonly pro- Netting is becoming increasingly birds to disperse to others, causing tected under state laws, and in those popular as a solution to woodpecker damage to a greater number of trees. instances a state permit may be problems because it consistently gives required for measures that involve desired results. Frightening Devices lethal control or nest destruction. Metal barriers. Place metal sheathing Visual. Stationary model hawks or Other methods of reducing wood- or plastic sheeting over the pecked , fake and simulated snakes, and pecker damage do not infringe upon areas on building siding to offer per- and cat silhouettes are generally their legal protection status. Threat- manent protection from continued considered ineffective as repellents. ened or endangered species, however, damage. Like all repelling methods, Toy plastic twirlers or windmills fas- cannot be harassed. metal barriers work best if installed as tened to the eaves, and aluminum foil soon as damage begins. Occasionally or brightly colored plastic strips, bright Damage Prevention and the birds will move over to an unpro- tin lids, and pie pans hung from Control Methods tected spot and the protected area above, all of which repel by movement must be expanded. Aluminum flash- and/or reflection, have been used with some success, as have suspended fal- Exclusion ing is easy to work with to cover damaged sites. Woodpeckers will con silhouettes, especially if put in Netting. One of the most effective sometimes peck through aluminum if place soon after the damage starts. The methods of excluding woodpeckers they can secure a foothold from which twirlers and plastic strips rely on a from damaging wood siding beneath to work. Metal sheathing can be dis- breeze for motion. Stretching reflective the eaves is to place lightweight plastic guised with paint or simulated wood mylar tape strips across a damaged bird- netting over the area. A grain to match the siding. area, or attaching them to the eaves mesh of 3/4 inch (1.9 cm) is generally and letting them hang down (weighted Quarter-inch (0.6-cm) hardware cloth recommended. At least 3 inches (7.6 or unweighted) is a recent alternative has also been used to cover pecked areas cm) of space should be left between to aluminum strips. Large rubber bal- and prevent further damage. It can be the netting and the damaged building loons with owl-like eyes painted on spray painted to match the color of the so that birds cannot cause damage them are included in the recent array building. The wire can either be attached through the mesh. The netting can also of frightening devices used to scare directly to the wood surface being dam- be attached to the overhanging eaves woodpeckers. aged, or raised outward from the and angled back to the siding below wood siding with 1-inch (2.5-cm) wood A good deal of attention has recently the damaged area and secured taut but spacers. been given to round magnifying-type not overly tight (Fig. 3). Be sure to shaving mirrors installed over or adja- secure the netting so that the birds Once the woodpeckers have been dis- cent to damaged areas to frighten have no way to get behind it. If in- couraged, frightened away, or killed, woodpeckers with their larger-than- stalled properly, the netting is barely the damaged spots on houses should life reflections. Success is sometimes visible from a distance and will offer a be repaired by filling in the holes with reported by those using the method long-term solution to the damage wood patch or covering them to pre- and this encourages further testing. problem. If the birds move to another vent woodpeckers from being at- Contrarily, woodpeckers are not dis- area of the dwelling, that too will need tracted to the damaged site at some couraged from damaging wooden to be netted. future time. window frames or casings very near to

E-142 window panes where their own reflec- is of doubtful merit. It is unlikely that Live traps have been tried in attempts tion would frequently be seen. In fact, high enough odor-repelling concentra- to capture woodpeckers for possible some believe that seeing their own tions of napthalene could be achieved relocation rather than killing the birds. reflection intensifies the damage as a to effectively repel woodpeckers. None of those explored were very suc- result of defensive territorial behavior. cessful, and more research is needed to Odorous and somewhat toxic wood develop an effective woodpecker live Sound. Loud noises such as hand- treatments, such as creosote and pen- trap. clapping, a toy cap pistol, and banging tachlorophenol, which are frequently on a garbage can lid have been used to used to treat utility poles and fence Shooting frighten woodpeckers away from posts, do not resolve the woodpecker houses. Such harassment, if repeated problem. Where it is necessary to remove the when the bird returns, may cause it to offending birds and the proper permits Tactile. Sticky or tacky bird repel- leave for good. have been obtained, shooting may be lents such as Tanglefoot®, 4-The- one of the quickest methods of dis- Propane exploders (gas cannons) or Birds®, and Roost-No-More®, smeared patching one or a few birds. The dis- other commercial noise-producing, or placed in wavy bands with a caulk- charging of firearms is often subject to frightening devices may have some ing gun on limbs or trunks where local regulations in residential areas. merit for scaring woodpeckers from sapsuckers are working, will often dis- commercial orchards, at least for short courage the birds from orchard, orna- At close range, air rifles or .22-caliber periods. Because of the noise they pro- mental, and shade trees. These same rifles with dust shot or BB caps can be duce, they are rarely acceptable near repellents can be effective in discour- effective. Shotguns or .22-caliber rifles inhabited dwellings or residential aging birds if applied to wood siding may be needed for birds that must be areas. Around homes, portable radios and other areas of structural damage. taken from greater distances. Consid- have been played with little success in The birds are not entrapped by the erable discretion must be used around discouraging woodpeckers. Expensive sticky substances but rather dislike the dwellings. Bullets and shot can travel high-frequency sound-producing tacky footing. A word of caution: some long distances if they miss their devices are marketed for controlling of the sticky bird repellents will dis- targets. various birds but rarely provide color painted, stained, or natural wood With appropriate permits, shooting advertised results. High-frequency siding. Others may run in warm has been occasionally used to reduce sound is above the normal audible weather, leaving unsightly streaks. It is woodpecker damage in commercial hearing range of humans but, unfor- best to try out the material on a small fruit and nut orchards. tunately, above the range of most out-of-sight area first before applying birds too. it extensively. The tacky repellents can Other Methods be applied to a thin piece of pressed Woodpeckers can be very persistent board, ridged clear plastic sheets, or Suet. Placing suet stations near dam- and are not easily driven from their other suitable material, which is then aged buildings, especially in colder territories or selected pecking sites. For fastened to the area where damage is parts of the country, has been recom- this reason, visual or sound types of occurring. For sources of sticky or mended to entice woodpeckers away frightening devices for protecting tacky bird repellents, refer to Supplies from buildings or damaged areas. Suet buildings — if they are to be effective and Materials. offered in the warmer seasons of the at all — should be employed as soon year, however, may be potentially as the problem is identified and before Toxicants harmful to woodpeckers. The suet gets territories are well established. Visual onto the feathers of the head, which and sound devices often fail to give Toxicants have only rarely been used to may lead to matting and eventual loss desired results and netting may have protect fruit crops. Woodpecker prob- of feathers. Some damage control ex- to be installed. lems can be resolved without toxicants perts believe that any feeding of birds and none are registered for such use. contributes to the problem and recom- Repellents mend against it. Trapping Taste. Many chemicals that have Nest boxes. All North American Wooden-base rat snap traps can be ef- objectionable tastes as well as odors woodpeckers are primarily cavity fective in killing the offending birds. have been tested for treating utility nesters that excavate their own cavi- Federal and, most likely, state permits poles and fence posts to discourage ties, but some of these species, such as are required. The trap is nailed to the woodpeckers. Most have proven inef- golden-fronted, hairy, red-bellied, building with the trigger downward fective or at least not cost-effective. and red-headed woodpeckers, do alongside the spot sustaining the dam- Odor. occasionally use existing cavities or Naphthalene (mothballs) is a age. The trap is baited with nut meats nest boxes (Fig. 4). volatile chemical that has been sug- (walnuts, almonds, or pecans) or suet. gested for woodpecker control. In out- If multiple areas are being damaged, Northern flickers apparently use artifi- of-door unconfined areas, however, it several traps can be used. cial boxes more often than any other

E-143 ers are after insects, some control bul- letins suggest treating -infested siding with an appropriate insecticide as a remedy for damage. While this may have some merit with insect- infested wood, woodpeckers often attack siding, poles, and posts that are sound and without insects. The use of insecticides for indirect control in these instances would be unfounded. Depending on their chemical nature, insecticides may have an adverse effect on the birds. Where the situation warrants the application of an insecti- cide, it should be selected on the basis of its safety for birds. Economics of Damage and Control

Little has been published on the eco- nomics of damage to buildings and other human-made structures. Most of what does exist relates to damage to utility poles because companies keep good records of these losses and the cost of replacements. For example, from 1981 to 1982 the Central Missouri Electric Cooperative replaced 2,114 woodpecker-damaged poles in their system at an estimated cost of Fig. 4. Artificial nest boxes are used by some species, especially the northern flicker. $560,000. Economic losses to the tim- ber industry in terms of damaged trees and reduction in wood quality have woodpecker species. Some success has or sound methods have failed and also been documented in several been achieved with the placement of where woodpecker populations are regions. Such published information is cavity-type nest boxes on the building desired. Nesting woodpeckers defend of a localized nature; the extent of in the vicinity of damage by northern their territories and keep other wood- damage on a nationwide basis is flickers. A thick layer of peckers away. What effect such boxes unknown. Little is published on the should be placed in the bottom of the will have on increasing local wood- economic damage to buildings, box; better yet, some have found that pecker populations is unknown. although it is known to be substantial filling the box completely full of - Nest boxes are constructed of wood in some instances. In a survey of dust entices the bird to remove the with an entrance hole 16 to 20 inches woodpecker damage to homes, Cra- sawdust to the desired level. Possibly, (40 to 50 cm) above the floor and about ven (1984) reported an average loss of the bird is fooled into thinking it is 2 1/2 inches (6 cm) in diameter. Inside $300 per bird incident. Damage to constructing its own nest. Working floor dimensions should be about 6 x 6 homes was estimated at $50,000 to against the nest box is the fact that inches (15 x 15 cm) and the total height $500,000 annually in Michigan, a con- with primary cavity nesters, the prepa- of the box is 22 to 26 inches (56 to 66 servative $50,000 in Louisiana, and ration of the new cavity often seems a cm). A front-sloping hinged roof will over $100,000 in Wisconsin. part of the breeding ritual. New cavi- shed rain and provide easy access. ties are often constructed even where The economics of control are relatively Place the boxes at about the same preexisting empty cavities are avail- unknown because in most situations it height as the height of the structural able. is difficult to predict what the damage damage. might have been if no control was The use of nest boxes is definitely Insecticides for indirect control. undertaken. worth trying in an area where visual Based on the premise that woodpeck-

E-144 Acknowledgments

Information used in this section draws upon the author’s personal experience and a variety of scientific and applied references and extension leaflets. Figures 1 and 2 by Emily Oseas Routman. Figure 3 from W. P. Gorenzel and T. P. Salmon (1982). Figure 4 by Renee Lanik, University of Nebraska-Lincoln.

For Additional Information

Carlton, R. L. 1976. Woodpeckers and houses. Coop. Ext. Serv., Univ. Georgia, College of Agric. Leaflet 239. 6 pp. Craven, S. R. 1984. Woodpeckers: A serious suburban problem? Proc. Vertebr. Pest Conf. 11:204-210. Dennis, J. V. 1967. Damage by golden-fronted and ladder-backed woodpeckers to fence and utility poles in South Texas. Wilson Bull. 79:75-88. Evans, D., J. L. Byford, and R. H. Wainberg. 1984. A characterization of woodpecker damage to houses in East Tennessee. Proc. Eastern Wildl. Damage Control Conf. 1:325-330. Gorenzel, W. P., and T. P. Salmon. 1982. The cliff — biology and control. Proc. Vertebr. Pest Conf. 10:179-185. Henderson, F. R., and C. Lee. 1992. Woodpeckers. Coop. Ext. Serv. Kansas State Univ., Manhattan. Leaflet L-866. 5 pp. Jackson, J. A., and E. E. Hoover. 1975. A potentially harmful effect of suet on woodpeckers. Bird-Banding 46:131-134. Linn, J. W. 1982. Woodpeckers. Pest Control 50(6):28, 30. Marsh, R. E., and W. E. Howard. 1990. Vertebrate Pests. Pages 771-831 in A. Mallis, ed. Handbook of pest control 7th ed. Franzak and Foster Co., Cleveland, Ohio. Stemmerman, L. A. 1988. Observation of woodpecker damage to electrical distribution line poles in Missouri. Proc. Vertebr. Pest Conf. 13:260-265. US Fish and Wildlife Service. 1978. Controlling woodpeckers. US Dep. Inter., Fish Wildl. Serv. ADC 101. 4 pp.

Editors Scott E. Hygnstrom Robert M. Timm Gary E. Larson

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