Red-cockaded Woodpecker Research Articles

Breeding Bird Response to Midstory Hardwood Reduction in Florida Sandhill Longleaf Pine Forests

The dramatic loss and degradation of longleaf pine (Pinus palustris) forests in the southeastern United States have contributed to the declines of several bird species associated with this ecosystem. We examined breeding bird response to habitat restoration in longleaf pine sandhill forests of northwest Florida, USA. We compared habitat variables and abundance of breeding birds among 3 hardwood reduction techniques (prescribed spring burning, herbicide application, mechanical felling-girdling) and maintenance of fire exclusion (control). We also examined abundance of breeding birds in fire-maintained, non-experimental reference sites as a means to gauge management success based on similarity analysis. All 3 hardwood reduction methods decreased midstory hardwoods and canopy cover, and increased herbaceous cover compared with fire-suppressed control plots, but had little effect on longleaf pine basal area. Midstory hardwood reduction methods increased the similarity of the breeding bird species assemblages to those found in the reference plots, compared with the fire-excluded control plots. Species that most strongly contributed to the similarity between the hardwood reduction and the reference plots were, in decreasing order of importance: red-cockaded woodpecker (Picoides borealis), red-headed woodpecker (Melanerpes erythrocephalus), tufted titmouse (Baeolophus bicolor), and brown-headed nuthatch (Sitta pusilla). Depending on the similarity index used, additional but weaker contributors to the similarity between the hardwood reduction and the reference plots were northern cardinal (Cardinalis cardinalis), Bachman's sparrow (Aimophila aestivalis), and Carolina chickadee (Poecile carolinensis). Species associated with hardwoods (e.g., tufted titmouse, northern cardinal, Carolina chickadee) contributed to greater similarity of the reference condition by decreasing in abundance after hardwood reduction, whereas open-habitat species increased in numbers, compared with birds on the fire-excluded control plots. Only the detection rates of cardinals and Carolina chickadees were not different among hardwood reduction methods. Two notable species of concern that increased in all hardwood reduction plots compared with the control, but were not strong contributors of the similarity to the reference condition, were northern bobwhite (Colinus virginianus) and southeastern American kestrel (Falco sparverius paulus). Our results suggest that these management methods were beneficial to landbirds characteristic of fire-maintained longleaf pine sandhills in northwest Florida. However, northern bobwhites and Bachman's sparrows may require more intensive management than red-cockaded woodpeckers, such as shorter burn intervals, as these species depend directly on ground cover vegetation. We recommend prescribed spring burning as the most economical and ecologically desirable method for managing breeding bird habitat in longleaf pine sandhill forests.

Safe Harbor for the Red-Cockaded Woodpecker: Private Forest Landowners Share Their Views

Abstract We surveyed North Carolina and South Carolina private forest landowners to learn their attitudes about the Safe Harbor Program initiated by the US Fish and Wildlife Service and the Environmental Defense Fund. Landowners who own large amounts of forestland near active clusters of red-cockaded woodpeckers (Picoides borealis), whose forests have a high proportion of mature pine, and who practice prescribed burning or chemical or mechanical methods to control understory hardwoods are most likely to sign an agreement to participate. We found that the views of program participants and nonparticipants were similar concerning the Endangered Species Act and the alternatives to the Safe Harbor Program.

Focus on ... Private Forest Landowners: How to Provide Woodland Habitat for the Red-Cockaded Woodpecker

Abstract Landowners who follow these rules will be contributing to the survival of a most interesting inhabitant of our southern pine woodlands.

Inbreeding and experience affect response to climate change by endangered woodpeckers.

In recent decades, female red-cockaded woodpeckers (Picoides borealis) have laid eggs increasingly earlier in response to a changing climate, as has been observed in several other bird species breeding at north temperate latitudes. Within each year, females that lay earlier are more productive than females that lay later. However, inexperienced females, experienced females who change mates and inbred birds have not adjusted to the changing climate by laying earlier, and have suffered reproductive costs as a result. Failure to respond to global climate change may be a further example of the reduced ability of inbred animals to respond to environmental challenges.

RED-COCKADED WOODPECKER FORAGING BEHAVIOR IN RELATION TO MIDSTORY VEGETATION

Red-cockaded Woodpeckers (Picoides borealis) nest and forage in pine-dominated forests. Research indicates that substantial hardwood midstory encroachment is detrimental to Red-cockaded Woodpecker populations, although the exact mechanisms are unknown. We examined foraging behavior in relation to midstory between August 1989 and February 1990. Red-cockaded Woodpeckers foraged at greater heights in areas of taller and denser midstory in the loblolly-shortleaf pine (Pinus taeda and P. echinata, respectively) habitat, but not in longleaf pine (P. palustris) habitat with less-developed midstory vegetation than typical of loblolly-shortleaf pine habitat. In addition, Red-cockaded Woodpeckers concentrated foraging activities in or adjacent to forest stands or openings with reduced midstory vegetation. Overall, Red-cockaded Woodpeckers foraged disproportionately at heights and sites that minimized their exposure to dense midstory conditions. These results suggest that ecosystem management, preferably using prescribed fire, that reduces midstory vegetation will improve foraging habitat for Red-cockaded Woodpeckers.

Influence of hardwood midstory and pine species on pine bole arthropods

Arthropod density on the boles of loblolly pines ( Pinus taeda) was compared between a stand with and stand without hardwood midstory and between a stand of loblolly and shortleaf pines ( P. echinata) in the Stephen F. Austin Experimental Forest, Nacogdoches Co., Texas, USA from September 1993 through July 1994. Arthropod density was greatest ( t=5.67, 10 d.f., P<0.001) in an open pine stand nearly devoid of hardwood midstory than in a pine stand with dense hardwood midstory. Loblolly pine had greater ( t=2.34, 10.9 d.f., P=0.040) arthropod densities than shortleaf pine. Vegetative characteristics within a pine stand rather than bark rugosity appear to be the dominant factor determining arthropod density on the boles of pines. The red-cockaded woodpecker ( Picoides borealis) should benefit from greater abundances of arthropods on the boles of pines particularly during the nesting season. In order to provide prime foraging habitat for the red-cockaded woodpecker, land managers should consider the vegetative community structure within foraging habitat.

The red-cockaded woodpecker: surviving in a fire-maintained ecosystem

The red-cockaded woodpecker: surviving in a fire-maintained ecosystem

Does the availability of artificial cavities affect cavity excavation rates in Red-cockaded Woodpeckers?

Rates of cavity excavation by Red-cockaded Woodpeckers (Picoides borealis) were examined from 1983 to 1999 on the Angelina National Forest in east Texas. We compared the rate of natural cavity excavation between 1983 and 1990 (before artificial cavities were available) with the rate of cavity excavation between 1992 and 1999, a period when artificial cavities were regularly installed within active woodpecker cavity-tree clusters. Our comparison was restricted to cavity-tree clusters in longleaf pine (Pinus palustris) and loblolly (P. taeda)-shortleaf (P. echinata) pine habitats where woodpecker groups were present for the entire period between 1983 and 1999. Excavation rate of new cavities was significantly higher in longleaf pine habitat when artificial cavities were not available than during the subsequent period when artificial cavities were provided in all active cavity-tree clusters. In loblolly-shortleaf pine habitat, we did not detect a significant difference in the rate of new cavity excavation between the periods before and after the use of artificial cavities. We attribute the difference in results between habitats to a relative scarcity of cavities in loblolly-shortleaf pine sites due to a higher bark beetle-induced cavity tree mortality.

Effects of helpers on breeder survival in the red-cockaded woodpecker ( Picoides borealis )

Helpers can gain future indirect fitness benefits by increasing the survival of breeders that produce offspring related to the helper. Helping augments group size through the helper's presence and, in some cases, by increasing fledging success. Breeders may then experience enhanced survivorship because of the benefits of living in large groups. Helping may also reduce the workload of the breeder, which in turn may increase the likelihood that the breeder will survive to breed again. We used Cox's proportional hazards model to examine whether breeders' survival in two populations of the red-cockaded woodpecker (Picoides borealis) was enhanced when group size was increased in the presence of (1) the helper itself, or (2) "extra" fledglings (fledglings produced by the breeder because of helping behavior). We found that in the presence of helpers, the risk of a breeder dying declined by 21–42% for males and 0–14% for females. Our results suggest reduced breeder workload as one mechanism to explain reduced breeder mortality in the presence of helpers: breeders spent less time incubating and provisioning nestlings when assisted by helpers. The risk of a breeder dying declined by 16–42% in males and 26–43% in females in the presence of "extra" fledglings. We speculate on possible mechanisms by which fledglings might affect breeder survival. Our results support the hypothesis that helpers gain future indirect benefits by reducing breeder mortality.

Low Frequency of Site Fidelity by Golden-Fronted Woodpeckers

Interest in site fidelity is rooted in its influence on population structure, including dispersal and recruitment (Shields, 1984). Familiarity with the local habitat is increased through fidelity, which in turn may enhance defendability and access to the best nesting, staging, and wintering sites. Factors proposed that might influence the degree of site tenacity include age, sex, local habitat and nest-site stability, and prior breeding experience (Shields, 1984). Ideally, statistical analysis of site fidelity should include data on mortality-survival rates and dispersal distance. For the golden-fronted woodpecker (Melanerpes aurifrons) these data are unavailable (Husak and Maxwell, 1998) so we discuss site faithfulness in this species relative to that documented for congeners. Fidelity has been documented among migratory and non-migratory birds (e.g., Freer, 1979; Greenwood, 1980; Shields, 1984; Blancher and Robertson, 1985; Rimmer and Darmstadt, 1996; Flint et al., 2000; Weggler, 2000), but few studies have focused on woodpeckers. In North America, nest-site fidelity has been documented in red-cockaded (Picoides borealis; Jackson, 1994), red-headed (Melanerpes erythrocephalus), and red-bellied (M. carolinus) woodpeckers (Ingold, 1991), and migratory northern flickers (Colaptes auratus), and yellow-bellied sapsuckers (Sphyrapicus varius; Lawrence, 1967). The only site fidelity data for golden-fronted woodpeckers prior to our research involved anecdotal observations of re-use of nest sites over

Restoration of the longleaf pine ecosystem on private lands in the US South: an ecological economic analysis

The longleaf pine ecosystem is one of the most biologically diverse in North America, supporting hundreds of plant and animal species. Because of its timber and many non-timber benefits, there is strong interest among forestry professionals, conservation groups, and the public at large in restoring longleaf pine ecosystems. However, many landowners are reluctant to grow longleaf pine on their lands on a commercial basis because the economic returns from longleaf pine timber production are usually less than those of slash pine. In this study, we develop a model that determines the profitability of longleaf and slash pine timber production after consideration of carbon sequestration, habitat for the endangered red-cockaded woodpecker, and other amenity benefits. Results suggest that internalizing carbon sequestration benefits and red-cockaded woodpecker habitat benefits alone is not enough for landowners to switch from slash pine to longleaf. Additional payments of $16 to 33 per ha per year, reflecting extra amenity benefits associated with longleaf pine relative to slash pine, make longleaf production financially competitive. Incentives that reflect carbon, biodiversity, and amenity benefits associated with longleaf production may be the optimal way of restoring longleaf pine ecosystems on rural private lands in the US South.

POPULATION VIABILITY ANALYSIS FOR RED-COCKADED WOODPECKERS USING AN INDIVIDUAL-BASED MODEL

Red-cockaded Woodpeckers (Picoides borealis) are distributed in the southeastern United States among closed populations whose maximum size is limited. Previous population viability analyses for this species have been confined to examination of threats posed by catastrophes and loss of genetic variability, because of the lack of demographic models that incorporate the extreme spatial constraints on dispersal that characterize this species. We used a spatially explicit, individual-based simulation model to assess the vulnerability of Red-cockaded Woodpecker populations to demographic and environmental stochasticity. Vulnerability to these threats was relatively low, because the presence of a substantial nonbreeding class (i.e., helpers) ameliorated the impact of stochastic variation in mortality and reproduction on the size of the breeding population. Because dispersal of helpers is spatially restricted, this effect was most pronounced when territories were aggregated or at high densities. Populations of 250 and 500 territories were stable regardless of the level of territory aggregation at the densities examined, whereas populations of 25, 49, and 100 territories ranged from rapidly declining to stable, depending on territory density and level of aggregation. Techniques that enable managers to maintain existing territories and create new ones are well established for this species. Thus managers may reasonably expect to maintain even small populations of Red-cockaded Woodpeckers by increasing the density, level of aggregation, and number of territories.

Population Viability Analysis for Red-Cockaded Woodpeckers Using an Individual-Based Model

Population Viability Analysis for Red-Cockaded Woodpeckers Using an Individual-Based Model

Effects of Hardwood Reduction on Winter Birds in Northwest Florida Longleaf Pine Sandhill Forests

Abstract Reversing decades of fire exclusion by hardwood midstory reduction is now used to recover populations of the federally endangered Red-cockaded Woodpecker (Picoides borealis) in longleaf pine (Pinus palustris) forest ecosystems. The effects of Red-cockaded Woodpecker management on winter birds in longleaf pine sandhill forests are largely unknown. Examining habitat use of winter migrants, some of which are declining, may influence the selection of habitat management techniques used for Red-cockaded Woodpeckers to benefit overwintering migrants. During the winters (December–February) of 1997–1998 and 1998–1999, we tested experimentally the effects of hardwood reduction treatments applied in 1995 on winter birds at Eglin Air Force Base in fire-excluded northwest Florida longleaf pine sandhills. Treatments were (1) prescribed spring burning, (2) herbicide application, (3) mechanical felling and girdling, and (4) a control where decades of fire exclusion was maintained. We also sampled winter bird flocks in frequently burned, nonexperimental reference plots to measure management success. Hardwood reduction techniques had no effect on flock species richness, which averaged 7.9 and 7.2, respectively, during 1997–1998 and 1998–1999. Larger flocks in felling and girdling and in herbicide plots were primarily due to significantly higher numbers of overwintering Chipping Sparrows (Spizella passerina), as well as resident Red-cockaded Woodpeckers and an influx of temperate migrant Pine Warblers (Dendroica pinus). In contrast, flocks in control plots were smaller (flock size and species composition in spring burn plots were intermediate) and composed of hardwood-associated species, such as Tufted Titmouse (Baeolophus bicolor) and Carolina Chickadee (Poecile carolinensis). The relative uses of longleaf pines and hardwoods by Red-cockaded Woodpeckers, Pine Warblers, and Brown-headed Nuthatches (Sitta pusilla) during both winters best explained that winter birds present in herbicide, felling and girdling, and reference plots were more likely to forage on the same tree species and substrates than birds in spring-burned plots, and least likely to forage on the same species and substrates as birds in the control plots. Those differences corresponded to the following increasing order of hardwood stem mortality among treatments: control, spring burn (41%), felling and girdling (62%), and herbicide (92%). Repeated burning is recommended to restore the reference foraging condition because it was eight times less expensive than other techniques, which favored mostly Chipping Sparrows.

Effects of Hardwood Reduction on Winter Birds in Northwest Florida Longleaf Pine Sandhill Forests

Reversing decades of fire exclusion by hardwood midstory reduction is now used to recover populations of the federally endangered Red-cockaded Woodpecker (Picoides borealis) in longleaf pine (Pinus palustris) forest ecosystems. The effects of Red-cockaded Woodpecker management on winter birds in longleaf pine sandhill forests are largely unknown. Examining habitat use of winter migrants, some of which are declining, may influence the selection of habitat management techniques used for Red-cockaded Woodpeckers to benefit overwintering migrants. During the winters (December–February) of 1997–1998 and 1998–1999, we tested experimentally the effects of hardwood reduction treatments applied in 1995 on winter birds at Eglin Air Force Base in fire-excluded northwest Florida longleaf pine sandhills. Treatments were (1) prescribed spring burning, (2) herbicide application, (3) mechanical felling and girdling, and (4) a control where decades of fire exclusion was maintained. We also sampled winter bird flocks in frequently burned, nonexperimental reference plots to measure management success. Hardwood reduction techniques had no effect on flock species richness, which averaged 7.9 and 7.2, respectively, during 1997–1998 and 1998–1999. Larger flocks in felling and girdling and in herbicide plots were primarily due to significantly higher numbers of overwintering Chipping Sparrows (Spizella passerina), as well as resident Red-cockaded Woodpeckers and an influx of temperate migrant Pine Warblers (Dendroica pinus). In contrast, flocks in control plots were smaller (flock size and species composition in spring burn plots were intermediate) and composed of hardwood-associated species, such as Tufted Titmouse (Baeolophus bicolor) and Carolina Chickadee (Poecile carolinensis). The relative uses of longleaf pines and hardwoods by Red-cockaded Woodpeckers, Pine Warblers, and Brown-headed Nuthatches (Sitta pusilla) during both winters best explained that winter birds present in herbicide, felling and girdling, and reference plots were more likely to forage on the same tree species and substrates than birds in spring-burned plots, and least likely to forage on the same species and substrates as birds in the control plots. Those differences corresponded to the following increasing order of hardwood stem mortality among treatments: control, spring burn (41%), felling and girdling (62%), and herbicide (92%). Repeated burning is recommended to restore the reference foraging condition because it was eight times less expensive than other techniques, which favored mostly Chipping Sparrows.

EFFECTS OF HARDWOOD REDUCTION ON WINTER BIRDS IN NORTHWEST FLORIDA LONGLEAF PINE SANDHILL FORESTS

Abstract Reversing decades of fire exclusion by hardwood midstory reduction is now used to recover populations of the federally endangered Red-cockaded Woodpecker (Picoides borealis) in longleaf pine (Pinus palustris) forest ecosystems. The effects of Red-cockaded Woodpecker management on winter birds in longleaf pine sandhill forests are largely unknown. Examining habitat use of winter migrants, some of which are declining, may influence the selection of habitat management techniques used for Red-cockaded Woodpeckers to benefit overwintering migrants. During the winters (December–February) of 1997–1998 and 1998–1999, we tested experimentally the effects of hardwood reduction treatments applied in 1995 on winter birds at Eglin Air Force Base in fire-excluded northwest Florida longleaf pine sandhills. Treatments were (1) prescribed spring burning, (2) herbicide application, (3) mechanical felling and girdling, and (4) a control where decades of fire exclusion was maintained. We also sampled winter bird flo...

Large-Scale Translocation Strategies for Reintroducing Red-Cockaded Woodpeckers

Translocation of wild birds is a potential conservation strategy for the endangered red-cockaded woodpecker (Picoides borealis). We developed and tested 8 large-scale translocation strategy models for a regional red-cockaded woodpecker reintroduction program. The purpose of the reintroduction program is to increase the number of red-cockaded woodpeckers by moving subadult birds from large populations to smaller populations that are unlikely to increase on their own. A major problem in implementing the program is determining where birds will be moved because the larger donor populations cannot supply enough birds for all small recipient populations each year. Our goals were to develop translocation strategies and model which ones would (1) result in the most groups of woodpeckers in a given amount of time, (2) most quickly reach the goal of at least 30 groups of woodpeckers in every population, and (3) result in the fewest population extinctions. We developed lump-sum strategies that moved all the translocated birds to 1 population each year, and partitioning strategies that divided the birds among several populations every year. In our simulations, the lump-sum strategies resulted in the most woodpeckers for the overall program and the highest number of population extinctions. Partitioning strategies had the lowest population extinction rate but produced the lowest rate of increase in the number of woodpecker groups. The model that partitioned birds to the 6 largest recipient populations with fewer than 30 groups was the best overall strategy for meeting our goals because it reached 30 groups in every population the fastest, produced many birds, and had only a moderate population extinction rate. We suggest that adhering to a single strategy that meets the goals of the participants should simplify the program and reduce its cost.

WOOD THRUSH MOVEMENTS AND HABITAT USE: EFFECTS OF FOREST MANAGEMENT FOR RED-COCKADED WOODPECKERS

Abstract We monitored adult and juvenile breeding-season movements and habitat use of radio-tagged Wood Thrushes (Hylocichla mustelina) at the Piedmont National Wildlife Refuge, central Georgia, USA. We investigated the effects that management for Red-cockaded Woodpeckers (Picoides borealis), thinning and burning >30 year old loblolly pine (Pinus taeda) habitat, had on Wood Thrushes, a ground-foraging and midstory-nesting species. Adult Wood Thrush pairs regularly moved long distances between nesting attempts (range 1 to 17,388 m). The only experimental effect we found on adult movements was a decrease in weekly emigration rates (Ψ) from thinned and burned compartments after silvicultural management. Adult males preferred riparian hardwoods with sparse to moderate cover and those preferences increased following management. Juveniles remained near their nest site (x = 177 m, SE = 113) for an average 24 days (SE = 6.3), and then dispersed a mean 2,189 m (SE = 342). Before dispersal, juveniles preferred upl...

Wood Thrush Movements and Habitat Use: Effects of Forest Management for Red-Cockaded Woodpeckers

Abstract We monitored adult and juvenile breeding-season movements and habitat use of radio-tagged Wood Thrushes (Hylocichla mustelina) at the Piedmont National Wildlife Refuge, central Georgia, USA. We investigated the effects that management for Red-cockaded Woodpeckers (Picoides borealis), thinning and burning &gt;30 year old loblolly pine (Pinus taeda) habitat, had on Wood Thrushes, a ground-foraging and midstory-nesting species. Adult Wood Thrush pairs regularly moved long distances between nesting attempts (range 1 to 17,388 m). The only experimental effect we found on adult movements was a decrease in weekly emigration rates (Ψ) from thinned and burned compartments after silvicultural management. Adult males preferred riparian hardwoods with sparse to moderate cover and those preferences increased following management. Juveniles remained near their nest site (x̄ = 177 m, SE = 113) for an average 24 days (SE = 6.3), and then dispersed a mean 2,189 m (SE = 342). Before dispersal, juveniles preferred upland hardwood–pine mixed habitat (P &lt; 0.05) with moderate overstory cover (P &lt; 0.05). We found no management effects on dispersal distances or predispersal habitat use. However, juveniles from thinned and burned compartments dispersed to hardwood habitats with dense cover, whereas birds from control compartments dispersed to pine-dominated habitats with sparse cover. All juveniles dispersed to areas with habitat similar to what they used before dispersal. Small-scale thinning and burning for Red-cockaded Woodpeckers may have had little effect on Wood Thrush habitat use and movements because typical movements were often larger than the scale (stand or compartment) targeted for management.

Wood Thrush Movements and Habitat Use: Effects of Forest Management for Red-Cockaded Woodpeckers

Wood Thrush Movements and Habitat Use: Effects of Forest Management for Red-Cockaded Woodpeckers