Management Techniques For The Red-Cockaded Woodpecker On Federal Lands Essay, Research Paper

Management Techniques For The Red-Cockaded Woodpecker On Federal Lands

Sean Fraser

NRM 304

ABSTRACT

The red-cockaded woodpecker (Picoides borealis) has been listed as an endangered

species since October, 1970. This species inhabits pine forests in the

southeastern United States where the majority of prime timberland is privately

owned. Private ownership of preferred habitat and historically destructive

silvicultural practices create unique problems for federal wildlife managers.

This report analyzes three management techniques being used to assess and

augment red-cockaded woodpecker populations on federal lands in the region,

primarily military installations. Seeking cooperation between diverse

government agencies, wildlife managers attempt to accurately assess species

abundance, alter woodpecker nesting cavities, and construct nest sites in an

effort to enhance red-cockaded woodpecker habitat on limited federal holdings in

the American southeast.

Key words: Picoides borealis, Global Positioning System, Geographic Information

System, cavity trees, cavity restrictors

The red-cockaded woodpecker (Picoides borealis) is an endangered species

that inhabits pine forests in an historical range from Texas to the Atlantic

coast (Jackson, 1986; Reed et al., 1988). Picoides borealis nest in clans or

family groups that usually consist of one breeding pair and 2 non-breeding male

helpers (Jackson, 1986 ). This group establishes and defends a territory that

includes foraging habitat and nesting “cavity trees” (Copeyon et al., 1991;

Jackson et al., 1986; Rossell and Gorsira, 1996). Red-cockaded woodpecker

clans excavate cavities in living pines, and have established a living and

foraging routine in conjunction with the southeastern pine forests and the

historical occurrence of fire, which reduces hardwood understory while sparing

fire-resistant pines (Jackson, 1986). Much of the prime nesting and foraging

habitat for this species has been systematically eliminated due to development,

timber harvest and intensive fire suppression (Jackson, 1986). The emergence

of dense hardwood understory and midstory as a result of fire suppression in

red-cockaded woodpecker habitat has resulted in the abandonment of many

otherwise undisturbed areas (Jackson, 1986; Kelly et al., 1993).

The red-cockaded woodpecker has been listed as endangered since 1970

(Federal Register, 1970 as cited by Ertep and Lee, 1994). Four requirements

for sustained red-cockaded woodpecker populations that are lacking in the

species historical range are identified as critical to species stabilization and

recovery: 1.) Open pine forests with shade tolerant understory controlled by

cyclical fire seasons; 2.) Old growth Pinus palustrus aged > 95 years and Pinus

taeda aged > 75 years; 3.) Approximately 200 acres for nesting group or clan;

4.) Multiple clans per area to maintain genetic stability and variability

(Jackson, 1986). The opportunity to establish or preserve these habitat

qualities on private timberland is largely lost due to historical harvest

practices and development, and research on expanding populations on federal

holdings is the most vital component in red-cockaded woodpecker stabilization

and recovery (Jackson et al., 1979a; Jackson, 1986). Exacerbating the problem

of habitat loss due to encroachment and fire-suppression are natural hazards

such as hurricanes, pine-beetle infestations and usurpation of red-cockaded

woodpecker cavities by other species (Carter et al., 1989; Rossell and Gorsira,

1996). Effects of historically natural hazards are multiplied in the context

of a diminished species abundance (Carter et al., 1989; Jackson, 1986).

Land management for wildlife is subject to unique difficulties in the

Southeast, as the majority of forested land is privately owned (Jackson, 1986).

In western states, approximately 2/3 of undeveloped land is federally

administered, making the enactment of widespread management policies feasible,

and controversies are apt to center around questions of access and use, rather

than the more difficult problems concerned with private property rights.

MATERIALS AND METHODS

This report will focus on the current techniques being explored and

enacted to stabilize and increase red-cockaded woodpecker populations on federal

lands throughout its previous range. Three areas of concern regarding the red-

cockaded woodpecker populations on federal lands interact to define current

management practices (Jackson, 1986). Wildlife biologists, foresters, and the

military have tested and combined specific techniques involving habitat

assessment and identification, cavity alteration, and cavity construction to

manage limited habitat for the red-cockaded woodpecker on federally administered

land (Carter et al., 1989; Copeyon, 1990; Ertep and Lee, 1994). Analysis

of specific studies and practices in these three areas serve as a description of

the technique for managing limited federal lands for the enhancement and

stabilization of red-cockaded woodpecker populations.

DISCUSSION

HABITAT ASSESSMENT AND IDENTIFICATION

A significant problem associated with the management of red-cockaded

woodpecker populations is obtaining an accurate assessment of habitat

availability and home range estimates (Ertep and Lee, 1994; Reed et al.,

1988). Differences in habitat quality and availability throughout the range of

the red-cockaded woodpecker affect population density and the range of foraging

and nesting activities within colonies, making general application of population

estimators difficult (Reed et al., 1988). This issue was addressed in 1988

during a study to evaluate red-cockaded woodpecker population indices. Reed et

al. (1988) set out to evaluate studies concerning red-cockaded woodpecker

population indices and, if necessary, develop a new techniques to more

accurately estimate adult population size. Reed at al. (1988) researched the

circular scale technique (CST) as described by Harlow et al. (1983) and found

that application of this method of population estimation is limited. CST

utilizes aerial identification of active cavity tree groups, and encompasses

said groups in a 460-m diameter circle that contains as many of the active

cavity trees as possible (Harlow et al., 1983 as cited by Reed et al., 1988).

While Harlow et al. (1983) and Lennartz and Matteaur (1986) used CST with great

accuracy in their study areas, estimating population sizes to between 92 and 95%

of the true number, the 1988 study by Reed et al. determined that the technique

cannot be used throughout the red-cockaded woodpecker range. Using CST in the

Sandhills region of North Carolina underestimated the number of groups in the

Reed et al. study population (Reed et al., 1988). In the Reed et al. (1988)

study area, red-cockaded woodpecker population density and the spatial

arrangement of colonies was frequently influenced by habitat fragmentation which

led to the violation of assumptions held necessary in the CST method of

population estimation (Reed et al., 1988). Conclusions in the Reed et al.

(1988) study indicate that CST may be generally used as an index, but further

research is necessary to establish a universal technique to estimate red-

cockaded woodpecker populations.

The development of sophisticated computer programs and topographical

analysis techniques may make assessment of red-cockaded woodpecker habitat and

species abundance more accurate and less time consuming (Ertep and Lee, 1994;

Reed et al., 1988). These advancements in geographic analysis and terrain

assessment technology have provided for an unlikely union between wildlife

managers and natural resource agencies on US military installations throughout

the southeast (Ertep and Lee, 1994; USMC, 1995). The coordination of

Geographic Information System programs (GIS) and Digital Multispectral

Videography (DMSV) at Fort Benning , Georgia adds a new technological advantage

in the search for red-cockaded woodpecker colonies and habitat by accurately

identifying longleaf pine stands (USACE, 1996). Image analysis and confirming

Global Positioning System information has been validated in initial tests by the

confirmation of three GIS and DMSV-identified red-cockaded woodpecker sites

through direct ground observation in the areas (USACE, 1996). Research is

ongoing to examine the initial findings associated with these new and highly

technical habitat assessment techniques (Ertep and Lee, 1996).

CAVITY ALTERATION

A significant problem in the recovery of red-cockaded woodpecker

populations involves the usurpation of nesting cavities by other species,

primarily southern flying squirrels (Gloucomys volans), northern flickers

(Colaptes auratus), European starlings (Sturnus vulgaris), and other species of

woodpeckers (Carter et al., 1989; Rossell and Gorsira, 1996). Invasive

species occupy or significantly alter cavities, preventing their continued use

by red-cockaded woodpeckers (Carter et al., 1989). Many nesting locations take

months or years to construct, and adequate old-growth pines are now less

frequent in the red-cockaded woodpecker range (Walters, 1986). Wildlife

managers and foresters have experimented with altering or reinforcing red-

cockaded woodpecker nesting cavities to discourage these invaders. Carter et al.

(1989) describe specific techniques for cavity alteration. Three types of cavity

restrictors alter the character of the cavity entranceway, acting as a deterrent

to enlargement or access by other species (Figure 1). Cavity restrictors

generally consist of a camouflaged metal plate fastened over the cavity entrance

(Carter et al., 1989).

A study by Rossell and Gorsira (1996) demonstrates the importance of

specific cavity parameters in assessing the availability of nesting and roosting

cavities for red-cockaded woodpeckers. The results of their study showed that

red cockaded woodpeckers nested only in cavities with normal entrances (Rossell

and Gorsira, 1996). Even if cavities with enlarged entrances contained normal

chambers and were not occupied by competing species, red-cockaded woodpeckers

avoided them (Table 1). TABLE 1?Diurnal occupants versus entrance (ent.) and

chamber (ch.) characteristics of active red-cockaded woodpecker (Picoides

borealis) cavities in the Northeast Management Area, Fort Bragg, North Carolina,

May, 1993. (Rossell and Gorsira, 1996)

CAVITY CONSTRUCTION

Techniques to artificially create red-cockaded woodpecker cavities have

been initially successful on federal holdings such as Fort Bragg, North Carolina,

which holds one of the largest red-cockaded woodpecker populations on federally

administered lands (Copeyon et al., 1991; Rossell and Gorsira, 1996). The

technique and effectiveness of artificial cavity construction is best examined

by analyzing the physical characteristics of artificial red-cockaded woodpecker

cavities, and reviewing studies wherein the cavities are used as a management

tool (Copeyon, 1990; Copeyon, et al., 1991; Rossell and Gorsira, 1996).

Perhaps the most comprehensive study concerning artificial cavity construction

for the benefit of the red-cockaded woodpecker was conducted by Copeyon, Walters

and Carter as part of a ten year study of red-cockaded woodpecker populations in

the Sandhills region of North Carolina (1991). Their work, Induction of Red-

Cockaded Woodpecker Group Formation by Artificial Cavity Construction, (Copeyon

et al., 1991) represents the most practical and valuable guide to red-cockaded

woodpecker population enhancement techniques to date (Conner and Rudolph, 1995).

In 1990, Carole Copeyon published an article describing a technique for

constructing artificial cavities for red-cockaded woodpeckers. Explaining that

excavation of suitable living cavities takes a minimum of ten months and

normally much longer to complete, Copeyon (1990) surmised that construction of

artificial cavities may be an effective management tool that would encourage

colonization of abandoned areas and reduce energy expenditure associated with

nesting cavity construction.

After making the decision to use artificial nesting cavities as a

management tool, wildlife managers should attempt to select older trees in their

respective areas of responsibility (Copeyon, 1990; Copeyon et al., 1991).

Selection of older trees mimics the natural inclination of the red cockaded

woodpecker and that older trees have sufficient heartwood development to support

large nesting and roosting cavities without sustaining damage (Copeyon, 1990).

As indicated previously, red-cockaded woodpeckers generally select trees between

80 and 100 years old depending on species availability. Copeyon (1990) reveals

that an adequate artificial nesting cavity requires an entrance approximately

4.4cm.-6.4cm. in diameter placed at 1-24 meters above ground level. An entrance

tunnel should be excavated into the heartwood with the nesting chamber extending

down at a right angle to the entrance tunnel to a depth between 20.3 and 27.3cm.

(Figure 2) (Copeyon, 1990). Small resin wells are drilled around the tree

above and below the entrance site (Copeyon 1990; Rossell and Gorsira, 1996).

Seepage from these wells act to discourage competitors and predators (Copeyon,

1990).

The results of Copeyon’s initial study concerning red-cockaded

woodpecker cavity construction are contained in (Table 2). TABLE 1. ?Use of

artificial cavities by red-cockaded woodpeckers (Picoides borealis) in the

Sandhills region of North Carolina (Copeyon, 1990).

SpeciesAge #Constructed

#Active LongleafOld

2925

Moderate7

4

Young2

2

Total38

31

LoblollyOld4

3

Young2

1

Total6

4

Cavity construction for red-cockaded woodpecker management is an

effective tool for inducing the formation of new colonies in the species’

historical range, and may prove to increase reproductive success in already

established colonies (Copeyon et al., 1991).

RESULTS

Further research is necessary to establish the impact of management for

the red-cokaded woodpecker on other species (Masters et al., 1996). Initial

studies indicate that management practices involving the clearance of hardwood

understory and the initiation of prescribed burns in red-cockaded woodpecker

habitat increase forage for white-tailed deer (Odocoileus virginianus) (Masters

et al., 1996). Studies continue to examine concerns about possible negative

effects of single species management practices in association with red-cockaded

woodpecker recovery effort (Masters et al., 1996). In the 25 years since the

identification of the red-cockaded woodpecker as an endangered species,

establishing a unified recovery program among the diverse federal agencies

responsible for the administration of lands within the species’ range has been

difficult (Jackson, 1986). In the first 15 years of listing, no programs

existed to effectively manage habitat for the red-cockaded woodpecker. Jackson

(1986) described the situation as especially urgent, as the red-cockaded

woodpecker was becoming dependent on widely dispersed islands of habitat,

isolating colonies and creating the potential for catastrophic losses due to

natural occurrences and inter-species competition for roosting and nesting sites.

Since 1986, research into habitat requirements for successful red-cockaded

woodpecker colonies have been identified (Copeyon et al., 1991; Jackson, 1986).

Improvements in identifying suitable habitat, altering existing cavities to

decrease competition for roosting and nesting sites, and initiating formation of

red-cockaded woodpecker colonies through construction of artificial cavities

have been synthesized into a specific technique of managing federal lands for

the red-cockaded woodpecker (Copeyon et al., 1991; Ertep and Lee, 1994;

Rossell and Gorsira, 1996).

393