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The Red-Cockaded Woodpecker at Carolina Sandhills NWR
Contents:
Meet the red-cockaded woodpecker...
Hear the song of the red-cockaded woodpecker
Habitat of the red-cockaded woodpecker...
Family groups and clusters...
Nesting cavities...
Why did the red-cockaded woodpecker disappear?...
Red-cockaded woodpecker recovery plans...
Meet the red-cockaded woodpecker...
In the vast stands of centuries-old pines that once stretched from the Atlantic Coast to the forests of eastern Oklahoma, the red-cockaded woodpecker (Picoides borealis) once thrived. But the farming practices of the European settlers and the progressive changes in timber management combined to drive this territorial, nonmigratory bird nearly to extinction. The red-cockaded woodpecker, often referred to simply as the "RCW," was placed on the endangered species list in 1970. While recovery efforts continue, the population is currently estimated by the USFWS to be roughly 12,500 birds living in about 5,000 family groups.
The red-cockaded woodpecker is about the size of the common cardinal or robin, approximately 7 inches long, with a wingspan of about 15 inches. Its back is barred with black and white horizontal stripes. The RCW's most distinguishing feature is a black cap and nape that encircle large white cheek patches. Rarely visible, except perhaps during the breeding season and when defending its territory, the male has a namesake small red streak -- called a cockade -- on each side of its black cap.
These small woodpeckers are unique in two ways. First, it is the only woodpecker that excavates its nesting and roosting cavities in living trees: preferably old-growth longleaf or loblolly pines. Second, the red-cockaded woodpecker lives within a tight-knit extended family community of breeding birds and helper birds.
In order to survive and prosper, the RCW requires open, parklike forested landscapes of longleaf pine and relatively large home ranges of up to 500 acres, which foster group interactions and population expansion. Mature longleaf pine trees are a necessity because the older trees often fall prey to a fungus called red-heart disease. This fungus softens the core of the tree, making it easier for the woodpecker to create its nesting and roosting cavities.
The RCW feeds primarily on wood-boring insects, beetles, wood roaches, ants, centipedes, caterpillars, and spiders; occasionally the adults will be observed feeding on blueberry, sweet bay berries, and poison ivy.
Habitat of the red-cockaded woodpecker...
The red-cockaded woodpecker makes its home in mature pine forests. Longleaf pines (Pinus palustris) are preferred, but other species of southern pine, such as the loblolly, are also acceptable. While other woodpeckers bore out cavities in dead trees where the wood is rotten and soft, the red-cockaded woodpecker is the only woodpecker that excavates its cavities exclusively in living pine trees. The mature pines favored by the RCW often suffer from a fungus called red heart disease, which attacks the center of the tree, causing the inner wood – or heartwood -- to become soft.
The southern pine ecosystems, once contiguous across large areas and kept open with recurring fire, provided ideal conditions for a nearly continuous distribution of red-cockaded woodpeckers throughout the South. The red-cockaded woodpecker's range extended from Florida to New Jersey and Maryland, as far west as Texas and Oklahoma, and inland to Missouri, Kentucky, and Tennessee. The range included the entire longleaf pine ecosystem, but the birds also inhabited open shortleaf, loblolly, and Virginia pine forests, especially in the Ozark-Ouachita Highlands and the southern tip of the Appalachian Highlands
Today those old southern pine forests are gone, and fewer trees are permitted to mature, creating a scarcity of pines suitable for woodpecker habitat. Approximately one percent of the red-cockaded woodpecker's historical habitat remains. Logging has claimed many of the ancient trees, and fire suppression has allowed a hardwood understory to encroach on the RCW’s habitat, making it undesirable for the birds. In a 2000 census, the US Fish and Wildlife Service estimated that there were 5,000 groups of red-cockaded woodpeckers -- approximately 12,500 birds – remaining. The majority of the remaining woodpeckers live in clusters (groups of cavity trees) along the eastern seaboard from Florida to Virginia, and west to southeast Oklahoma and eastern Texas.
Family groups and clusters...
Red-cockaded woodpeckers practice an advanced social system, living in extended-family groups. There is only one pair of breeding birds within each group, and they normally raise only a single brood each year. The other group members, called “helpers,” are usually males from the previous breeding season. Though helpers are non-breeders, they participate in incubation, feeding nestlings and fledglings, territory and cavity defense, and cavity excavation. Groups may contain as many as four helpers, but it is more common to see only one or two helpers per group.
A family group of red-cockaded woodpeckers will create a collection of cavity trees, called a “cluster.” Each bird in the group maintains its own cavity tree. Each group normally occupies and defends only one cluster. (click on the photo of a cluster for a larger image).
Red-cockaded family groups defend territories that cover an average of 200 acres, though some group territories are as small as 60 acres, and others as large as 600 acres have been observed. The size of a given territory is related to both habitat suitability and population density. This arrangement promotes continuity among family groups: Should the patriarch die, one of his offspring stands ready to inherit the family territory.
RCWs often have the same mate for several years. The nesting season lasts from April through June. The group helps to construct a nest made of wood chips in the breeding male’s roost cavity. The breeding female lays usually two to four small white eggs in this nest. Then the group helpers take over and incubate the eggs for 10 to 12 days. Once hatched, the nestlings remain in the nest cavity for about 26 days. Rearing the fledglings is a shared responsibility of the group. However, a single pair of RCWs can breed successfully without a group of helpers.
After several weeks, the fledges are largely independent. Juvenile females generally leave the group in the fall or winter, before the next breeding season, in search of solitary male groups. Some of the young males will leave at the same time in search of their own territory.
Nesting cavities...
The red-cockaded woodpecker creates its nesting and roosting cavities in living pines, usually old-growth longleaf or loblolly pines at least 80 years old. Older trees are more susceptible to red-heart fungus, which softens the wood and makes cavity construction easier. The RCW excavates an entrance hole of around 2 inches in diameter, leading to a gourd-shaped cavity, roughly 8 to 12 inches in diameter, into the heart of the tree. This is no small u
ndertaking…each cavity can take from 1 to 3 years to construct. Shown to the left is a typical entrance to a red-cockaded woodpecker cavity. (See the photo below for a side view of an actual nesting cavity.)
Once a cavity is completed, the RCW pecks numerous small holes -- called resin wells -- around the tree under the cavity. This causes large quantities of sap to run down the tree in rivulets, coating the tree and giving it a candle-like appearance. The sap theoretically deters rat snakes and other predators from reaching the cavity. The woodpeckers spend a significant amount of time and energy each day maintaining the flow of the resin wells. If the tree should die, or the damage from maintaining the wells becomes so great that the sap stops flowing, the woodpeckers will eventually abandon the cavity tree, potentially to other forest dwellers.
A number of other birds and small mammals use the cavities excavated by red-cockaded woodpeckers. Chickadees, bluebirds, and titmice will happily take up housekeeping in an RCW cavity. Several other woodpecker species, including the downy, hairy, and red-bellied woodpecker, may take over a RCW cavity, sometimes enlarging the hole enough to allow screech owls, wood ducks, fox squirrels and other mammals to later move in. Flying squirrels, several species of reptiles and amphibians, and insects, primarily bees and wasps, also will use RCW cavities. This makes the RCW an important part of the forest ecosystem, providing homes for many animals which would not normally choose to create a home in a living pine.
However, cavity competition is a major concern for those trying to revive this species. Sometimes, small mammals such as southern flying squirrel (Glaucomys volans) or larger woodpeckers don't wait until an RCW cavity is abandoned before moving in. And, once a red-bellied, red-headed, or pileated woodpecker enlarges the cavity entrance, it is rendered unsuitable for the red-cockaded woodpecker.
The amount of time it takes a RCW to excavate a cavity (from one to three years) is a huge detriment to any recovery program (see side view of actual cavity to the right). Carolina Sandhills Refuge staff uses artificial cavities as a part of their management plan to encourage population expansion of the red cockaded woodpecker.
The most common artificial cavity method used on the Refuge are insert boxes. Inserts are prefabricated wooden boxes containing a cavity similar to blue bird boxes (see photo of an artificial cavity before installation, below).
First, an appropriate longleaf pine is chosen, and a plug of the tree is removed using a chain saw. The complete cavity assembly – dubbed “government woodpecker housing” by one staff member -- is then inserted and secured. Once the artificial cavity is installed in the tree, wood putty is heaped on and modeled to mimic the look and texture of a longleaf pine (see a photo of an artificial cavity being installed).
Do the woodpeckers sneer at such housing? Not likely. Laura Housh, biologist on the Carolina Sandhills team, reports that several of the cavity inserts have been occupied by red-cockaded woodpeckers.
Why did the red-cockaded woodpecker disappear?...
The southern pine ecosystems, once contiguous across large areas and kept open with recurring fire, provided ideal conditions for a nearly continuous distribution of red-cockaded woodpeckers throughout the South. Today, approximately one percent of the red-cockaded woodpecker's historical habitat remains.
The disappearance of the red-cockaded woodpecker coincided with the loss of the longleaf pine ecosystem. As settlers and the early timber industry cut the forests, birds were isolated in tracts where trees deemed unmarketable were left standing. Aerial and ground photographs from the 1930s show scattered medium-to-large trees left in many stands. These culled trees at least for a time provided nesting and foraging habitat for the birds.
But the threat of a disappearing habitat continued. Beginning in the 1950s, the forest structure and composition changed dramatically, especially on lands managed for forest products. Accepted techniques such as clear cutting, short timber rotations, conversion of longleaf stands to other faster growing pine species, and "clean" forestry practices (removal of cavity, diseased, or defective trees) eliminated much of the remaining RCW habitat.
At the same time, aggressive fire suppression promoted the growth of a hardwood midstory in pine forests, choking out the open stands of longleaf pine with wiregrass ground cover sought by the RCW. The RCW has several natural predators that thrive in the cover of a midstory habitat, including the black rat snake. Agile tree climbers, rat snakes eat woodpecker eggs and nestlings. However, the red-cockaded woodpecker has an effective means of defense. It chips small holes (called resin wells) in the bark of the cavity tree, above and below the cavity. Sap from these holes oozes down the trunk of the tree. The sap adheres to the scales of the rat snake; even tiny amounts of resin apparently inhibit the movement of the scales, preventing the snake from climbing higher.
The loss of open pine habitat caused dramatic declines in the RCWs population; it was listed as an endangered species in 1970 (Federal Register 35:16047).
Red-cockaded woodpecker recovery plans...
The red-cockaded woodpecker was placed on the federal list of endangered species in 1970; in 1973 the species was afforded protection under the Endangered Species Act. Recovery of the red-cockaded woodpecker requires encouraging growth of larger pines, protecting corridors linking forested tracts, and restoring fire to its natural frequency, intensity, and seasonality, which spares the oldest trees and keeps the understory open. For more about the overall population status of the red-cockaded woodpecker and the Safe Harbor program, visit the site of the Clemson Field Office.
The largest populations of RCWs today are found within the historical longleaf pine ecosystem. Within the longleaf range, there are 4 populations with more than 200 groups, and 11 populations with more than 100 groups. All but one of these large population clusters are located on federal lands. Carolina Sandhills Refuge supports the largest population of RCWs on Fish and Wildlife Service land, with 140 clusters. The remaining longleaf pine-associated populations are small and isolated, continually threatened by predators, cavity competition, and the destruction of their habitat.
The Red-cockaded Woodpecker Recovery Plan (USFWS 1985) specifies that recovery will be achieved when 15 viable populations are established and protected by adequate habitat management programs. Each recovery population will likely require 400 breeding pairs -- or 500 active clusters, as some clusters are occupied by single birds or contain nonbreeding groups -- to ensure a sustained RCW population.
There is little evidence that red-cockaded woodpecker populations can expand to viable levels without considerable human intervention. The Carolina Sandhills Refuge uses a variety of approaches aimed at ensuring the survival of the red-cockaded woodpecker. These include:
- Managing the longleaf pine ecosystem, and using prescribed burns
- Installing and monitoring artificial nesting cavities
- Minimizing cavity competition from other species whenever feasible
- Monitoring population and nesting success
These ecosystem management plans promote practices that reduce landscape fragmentation, retain suitable numbers of potential cavity trees well distributed throughout the landscape, and restore the original forest floor cover. The use of growing-season fires to control hardwoods creates the required open forest condition to support RCW populations.
In another management program at the Carolina Sandhills Refuge, juvenile birds are translocated from stable larger populations into small ones; some young birds are also sent to other protected sites working with the red-cockaded woodpecker.
During the past 5 years, several RCW populations in the southern states have stabilized or increased as a result of integrating available technology with the RCW’s ecological requirements. Artificial cavities are an important element of this success.
The U.S. Forest Service, the U.S. Fish and Wildlife Service, and the U.S. Army each have management and recovery guidelines for their respective federal properties where the RCW will be recovered. The issues surrounding protection and management of red-cockaded woodpeckers on private lands are addressed through a private lands strategy, including a procedural manual for private landowners, Statewide Habitat Conservation Plans, and Memorandums of Agreement with industrial forest landowners.
In 1993, the Georgia-Pacific Company established a landmark conservation agreement with the US Fish and Wildlife Service to help protect the red-cockaded woodpecker on thousands of acres of company land. Since that time, two more companies, Hancock Timber Resource Group and Champion International Corporation, have established similar conservation agreements to protect the red-cockaded woodpecker on their lands, and other companies are currently working with US Fish and Wildlife Service to develop conservation agreements.
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