Relationships of red-cockaded woodpecker reproduction and foraging habitat characteristics in Arkansas and Louisiana

Abstract

Red-cockaded woodpecker (RCW; Picoides borealis) productivity is influenced by characteristics of forests in which they forage. Thus, we investigated the relationships between stand conditions and RCW reproduction. We conducted focal animal sampling two to three times per season for ten RCW groups from September 1999-September 2001 in southern Arkansas and northern Louisiana, USA. We measured overstory and understory vegetation characteristics associated with observed foraging sites. Mean diameter at breast height (DBH) of hardwood trees and autumn forb cover were inversely correlated with number of eggs laid. The numbers of eggs, hatchlings, and fledglings were similar between groups with and without helpers, though helpers tended to remain in higher quality habitat. Groups with helpers used foraging areas with greater basal area of pines (Pinus spp.) ≥25.4 cm DBH, conifer canopy cover, leaf litter cover, litter depth, autumn vine cover, and winter woody cover than groups without helpers. Our results suggested that foraging habitat recommendations should include understory conditions, although additional research is required to clarify the interrelationships between RCW reproduction, forest stand characteristics, and the arthropod community.

Red-Cockaded Woodpecker Foraging Behavior

“…Large hardwoods may indirectly reduce RCW reproductive success by limiting natural pine regeneration and herbaceous groundcover in foraging habitat, but the reported effects of these features on RCW reproductive success are themselves minimal. Furthermore, it is not clear if the negative effects of average hardwood vegetation metrics reported by Hardesty et al (1997) and Butler and Tappe (2008) were the result of canopy or midstory hardwood vegetation in RCW foraging habitat.…”

“…Convery (2002) reported a decline in fledgling production as the density of hardwoods 25.4 cm dbh increased. Butler and Tappe (2008) reported a decline in clutch size and nestling production (r 0.59 and r 0.33, respectively) as hardwood dbh increased and a decline in clutch size (r 0.36) as hardwood canopy cover (%) increased.…”

“…The three studies that directly examined the relationship between RCW reproductive success and the prevalence of large hardwood vegetation reported negative relationships, but did not explore the mechanisms involved (Hardesty et al 1997, Convery 2002, Butler and Tappe 2008. Large hardwoods may indirectly reduce RCW reproductive success by limiting natural pine regeneration and herbaceous groundcover in foraging habitat, but the reported effects of these features on RCW reproductive success are themselves minimal.…”

Range-Wide Meta-Analysis of Red-Cockaded Woodpecker Foraging Habitat Suitability

“…Two metrics were used to reflect the suitability and productivity of RCW territories: group size and the number of fledglings produced. Higher-quality territories have been shown to host larger groups of birds (Butler and Tapp 2008), and reproduction is thought to be associated with territory quality, although it has also been associated with other factors, including the age of dominant birds and number of helpers (Heppell et al 1994;Conner et al 2001). Group size and fledgling production at each territory were recorded at each study site during the breeding season (April-June).…”

“…Further studies in certain restored habitats indicated the impact of foraging habitat quality on RCW productivity. Larger group sizes, which generally indicated higher-quality territories (Butler and Tapp 2008), and greater fledging production were related to habitat features such as greater herbaceous groundcover, higher densities of large pines, and a reduced hardwood midstory (Hardesty et al 1997;James et al 1997James et al , 2001Walters et al 2002). These findings were used to develop a new Red-Cockaded Woodpecker Recovery Plan (USFWS 2003) that included two sets of guidelines for managing foraging habitat: the recovery standard and the standard for managed stability.…”