Richard N. Conner

Woodpecker Nesting Habitat in Cut and Uncut Woodlands in Virginia

In forest areas common flickers (Colaptes auratus) nested only in dead snags in 1to 12year-old clearcuts. Pileated woodpeckers (Dryocopus pileatus) nested in mature, dense stands with high basal area, and downy woodpeckers (Dendrocopos pubescens) nested in sparsely stocked stands with lower basal area. The hairy woodpecker (D. villosus) nested in stands intermediate to and overlapping the habitats selected by the pileated and downy woodpeckers. All nest cavities of the four species of woodpeckers were excavated in decayed wood of trees infected by fungal heart rots. Timber management may be detrimental to woodpeckers if all decayed trees are removed. Uncut filter strips along streams and roads appear to be of value as woodpecker nesting habitat. J. WILDL. MANAGE. 39(1):144-150 Optimum management of a forest for multiple benefits to humans requires intelligent coordination of practices. Little information exists for many nongame species of wildlife which will permit the forest manager to coordinate wildlife and timber management practices. This investigation was conducted to determine if the common flicker and the downy, hairy, and pileated woodpeckers on the Jefferson National Forest in Virginia had specific requirements for nest trees and the surrounding habitat or if they utilized a wide range of conditions.

Abiotic correlates of anuran calling phenology: the importance of rain, temperature, and season

ABSTRACT We surveyed anuran calls nightly at eight ponds in eastern Texas from 1 January 2001 through 31 December 2002. Air temperatures and daily rainfall also were recorded for each of the sites. Eastern Texas contains a diverse temperate anuran fauna and a climate that provides a range of conditions for anuran reproduction. During our study, we measured air temperatures that fluctuated seasonally with extremes from 0 to 29 C at 2100 h. We found rainfall to be generally abundant with occasional flooding events, however, prolonged periods of no precipitation were also observed. Given the level of anuran diversity and the amount of seasonal variation in temperature and rainfall in our temperate climate we expected to find a variety of breeding strategies. Results from our analyses did indeed suggest five basic breeding strategies based on anuran calling: (1) breeding within a predictable season (summer) independent of local weather patterns; (2) breeding opportunistically within a predictable season (summer) dependent on local rainfall; (3) breeding opportunistically within a predictable season (winter) dependent on local temperature; (4) breeding opportunistically dependent on local flood level rainfall events; (5) breeding opportunistically year round dependent on local temperature in the winter and local rainfall in the summer.

Snag Retention Increases Bird Use of a Clear-Cut

Birds were counted during the breeding season from 1977 to 1981 in 4 snag and 4 snagless plots (80 X 250 m) in an east Texas clear-cut to assess effects of snag retention on the bird community. After 4 years, 44 of the original 75 snags remained. Species richness, bird abundance, bird species diversity, and equitability were all higher (P < 0.05) in plots with snags than in snagless plots. Cavity-nesting birds occurred on plots with snags but were virtually absent from snagless plots. Other species used snags for foraging and perching and were more abundant on plots with snags. Retention or creation of snags is recommended for bird management in clear-cuts. J. WILDL. MANAGE. 47(3):799-804 Increased demand for wood products (U.S. Dep. Agric. 1973) has brought more intensive management of forests. Lands are being fully stocked with fast-growing trees and harvest rotations are being shortened. Present management trends increase homogeneity of commercial forests. Decaying wood in forest stands has no commercial value and is being eliminated. High-yield timber management replaces stands of snags (dead or dying trees) and old growth with young vigorous stands. Forest birds evolved in association with natural forest stands that usually contained substantial decayed wood. Birds use decaying wood for cavity nests, winter roost sites, and as a foraging substrate. Approximately 85 species of North American birds use cavities in dead or deteriorating trees (Scott et al. 1977); many of these birds occur in southern pine forests (LeGrand and Hamel 1980). Primary cavity nesters, e.g., woodpeckers, excavate their own nest cavity, mostly in decaying wood (Conner et al. 1975). Many of these cavities are later used as nest and roost sites by secondary cavity nesters. Balda (1975) found secondary cavity nesters composed approximately 50% of the breeding bird population in natural ponderosa pine (Pinus ponderosa) stands that contained substantial decayed wood. In southern forest ecosystems the role of snags and their relationships to birds have not been fully established. This study was designed to investigate the following questions: (1) what birds use snags and in what ways?, (2) can bird density and diversity in early-succession pine stands be i creased by maintaining snags?, and (3) how long do snags stand and how long do birds use them? We thank J. A. Jackson, B. R. McClelland, and V. E. Scott for reviewing a draft of this manuscript and the Southern Timberlands Division of St. Regis Paper Co. for use of their land for this study.

AVIAN COMMUNITY RESPONSE TO SOUTHERN PINE ECOSYSTEM RESTORATION FOR RED-COCKADED WOODPECKERS

Abstract The effects of Red-cockaded Woodpecker (Picoides borealis) management on nontarget birds is not widely known. Intensive management for pine specialists such as the Red-cockaded Woodpecker may negatively impact both Nearctic-Neotropical and Temperate Zone migrants associated with hardwood vegetation. To evaluate possible positive and negative associations, we surveyed avian communities from 1995–1997 using point counts within managed Red-cockaded Woodpecker cavity tree clusters and mature forest control sites in longleaf pine (Pinus palustris) and loblolly (P. taeda)-shortleaf (P. echinata) pine habitats. In general, sites managed for Red-cockaded Woodpeckers supported more diverse and numerous bird populations than mature forest control sites. During the breeding season in loblolly-shortleaf and longleaf pine habitats, respectively, species richness was 47% and 23% greater, avian abundance was 57% and 65% greater, and bird species diversity was 25% and 21% greater within managed Red-cockaded Woodpecker cluster sites than within control sites. During winter, species richness and avian abundance each were 52% higher within managed Red-cockaded Woodpecker cluster sites than control sites in loblolly-shortleaf pine habitat.

RED-COCKADED WOODPECKER NEST-CAVITY SELECTION: RELATIONSHIPS WITH CAVITY AGE AND RESIN PRODUCTION

We evaluated selection of nest sites by male Red-cockaded Woodpeckers (Pi- coides borealis) in Texas relative to the age of the cavity when only cavities excavated by the woodpeckers were available and when both naturally excavated cavities and artificial cavi- ties were available. We also evaluated nest-cavity selection relative to the ability of naturally excavated cavity trees to produce resin, which is used by the woodpeckers to maintain a barrier against predation by rat snakes (Elaphe spp.). Longleaf pines (Pinus palustris) selected by breeding males as nest trees produced significantly greater resin yields at 2, 8, and 24 h post-wounding than cavity trees used for roosting by other group members. This preference was observed in loblolly pine (I! taeda) and shortleaf pine (I? echinata) cavity trees only at the 2-h resin-sampling period. When only naturally excavated cavities were available, Red-cock- aded Woodpeckers in both longleaf pine and loblolly-shortleaf pine habitat selected thenew- est cavities available for their nest sites, possibly as a means to reduce parasite loads. When both naturally excavated and artificial cavity inserts were available, Red-cockaded Wood- peckers continued to select the newest cavity for nesting in loblolly-shor tleaf pine habitat but not in longleaf pine habitat. Resin production in existing longleaf pine nest trees re- mained sufficient for continued use, whereas resin production in loblolly pine and shortleaf pine nest trees decreased through time, probably because of woodpecker activity at resin wells. For these latter tree species, breeding males switched to newer cavities and/or cavity trees with higher resin yields. Received 7 )uly 1997, accepted 11 November 1997.

Width of Forest Streamside Zones and Breeding Bird Abundance in Eastern Texas

Abstract We evaluated breeding bird communities in forested streamside zones in eastern Texas to determine threshold widths of riparian forest that were associated with the addition of mature-forest-breeding birds and loss of shrub-breeding birds. We observed an association of shrub-breeding birds with narrow streamside zones and an increasing number of mature forest species within wider streamside zones. Streamside zones also provided song perches for many shrub breeding species. Although many bird species increased or decreased in a generally linear pattern as streamside zone width increased, some species appeared to have threshold widths associated with their presence. The Acadian Flycatcher (Empidonax virescens), Yellow-throated Vireo (Vireo flavifrons), and Yellow-billed Cuckoo (Coccyzus americanus) seemed to require at least 70 m of forest width before their abundance increased. In contrast, the Blue Grosbeak (Passerina caerulea), Painted Bunting (Passerina ciris), and Prairie Warbler (Dendroica discolor) decreased markedly at widths greater than 20 m and were absent after streamside zone widths increased beyond 70 m. We were unable to detect a relationship between streamside zone width and abundance of 11 species of birds. Uncut forested streamside zones within pine plantations provided a variety of habitat for forest-breeding and shrub-breeding birds that would not have been present had streamside zones been cut during harvesting operations. Our results provide important information to help forest managers balance the habitat requirements of both shrub-breeding and forest-breeding birds when they harvest timber in southern pine forests.

Vocalizations of common ravens in Virginia

--I tape recorded 1,210 vocalizations and observed the behavior of Common Ravens (Corvus corax) in southwestern Virginia from 1972 through 1976. Eighteen call types were identified and observed in conjunction with behavior at a communal roost, a landfill, and nest sites. I speculate that different call types were associated with excitement, agonistic interactions, aggression, alert, courtship, submission, and thwarting. Common Ravens in Virginia and handreared, captive ravens in Germany shared six call types, suggesting that the use of these call types may be innate. Although Common Ravens in Virginia, Alaska, and Germany gave many similar call types, locally learned call types may be present in each geographic area. Numbers of shared call types suggest that vocal behavior of ravens in Virginia resembles that of other North American ravens more than European ravens. The diversity and complexity of Common Raven (Corvus corax) vocal behavior have interested ornithologists and ethologists for years. Although ravens may be locally numerous at food sources, such as dumps (Mylne 1961, Dorn 1972, Brown 1974, Conner et al. 1975), and at communal nocturnal roosts (Cushing 1941, Coombes 1948, Lucid and Conner 1974), their populations are typically of low density, especially during the nesting season (Hooper et al. 1975). Their sparsity in number, coupled with their high intelligence (Bent 1946, Knight and Call 1980, Bruemmer 1984), extreme wariness, and frequently inaccessible nest sites, make it difficult to record their vocalizations within social context. Gwinner (1964) attempted to overcome these obstacles by studying hand-reared, captive ravens, but normal behavior and related vocalizations could have been altered by captivity. Studies in North America by Dorn (1972) and Brown (1974) included some aspects of Common Raven vocal behavior. Dorn recorded and made audiospectrograms of several different vocalizations, but he was unable to detect distinct behavioral associations with them. Brown (1974) recorded and made audiospectrograms on about 25 different vocalizations and described, in detail and when possible, display postures associated with many of the calls and their behavioral context. The Common Raven population in the central Appalachians is disjunct from the rest of the population in Canada and the United States (AOU 1983). Thus, vocal behavior of Common Ravens in Virginia may differ from other North American populations as well as from those in Europe. I sought to document the vocalizations and their social context in these birds, and compare my observations with those of comparable studies in North America and Europe. I was particularly interested to see how Gwinners (1964) findings on hand-reared, captive ravens applied to wild ravens. Such comparisons may provide insight on determining which aspects of raven vocal behavior are innate and which are learned.

Nitrogen Excretion by Turkey Vultures

-The proportions of nitrogen (N), as urate-N (76.1%), NH3-N (16.4%), and urea-N (7.5%) in the urine of fasted Turkey Vultures, are similar to those found in the urine of domestic chickens and ducks, the only other birds for which comparable data are available. Vultures show an adaptive increase in the percentage of urinary N excreted as urate (up to 86.8%) and a decrease in NH3-N (down to 8.9%) and urea-N (down to 4.3%) in the period after feeding on meat. These alterations in the proportions of nitrogenous wastes increase the efficiency of N excretion; fed birds excrete 4.8 times more N per milliliter of urinary water than fasted birds. The efficiency of N excretion during the 1.5-h period after feeding is comparable to that of the most efficient mammalian excretory systems. The elimination of urate (i.e., uric acid or any other urate compound) as the major nitrogenous excretory compound of birds generally is considered to be an adaptation for water conservation. Needham (1938) described the benefits of urate as a nitrogenous end product in cleidoic eggs; the potential osmotic advantage of urate excretion to adult birds is discussed in most current avian physiology texts (e.g., Sykes 1971, Shoemaker 1972, Sturkie 1976). The low solubility of urate in water (Peters and van Slyke 1946) and its ability to form colloids (Young and Dreyer 1933) might cause less osmotic water to be lost in urate excretion than might occur with osmotically active nitrogenous wastes. The advantages of urate excretion might be evident in two ways in species adapted to either water shortage or high demands for nitrogen (N) excretion relative to water availability: (1) by excretion of a consistently high proportion of urate or (2) by transient increases in the proportion of N excreted as urate, in response to either decreased water availability or high N intake. Regarding the first of these possibilities, previous studies of the proportions of nitrogenous excretory compounds have used only domestic chickens and ducks (e.g., Table II, Shoemaker 1972). While urate accounted for the largest proportion of the waste N in all studies, the percentages of urate-N ranged from 60 to 87% in chickens (see reviews by Sykes 1971, Shoemaker 1972). The only study on ducks (Stewart et al. 1968) reported a low proportion of urateN (54-57%), and it is tempting to speculate that this is a reflection of an abundant water supply with little selective pressure to conserve water. Studies of wild species with different drinking and feeding habits, and from different habitats, are needed to determine whether patterns of nitrogen excretion show long-range evolutionary adaptations. McNabb and McNabb (1975a) found no evidence of adaptive changes in the proportion of urate-N excreted by chickens when water availability was reduced to the minimum required for weight maintenance. While water was limited, chickens ate less high protein food rather than increase urate-N excretion. Moreover, studies such as that of Teekell et al. (1968) show no increase in the proportion of excreted urate over the range of 0-14% dietary protein. In contrast, Sykes (1971) presented data which suggest that fed chickens excrete a higher proportion of urate than fasted chickens. However, he gave only mean values from unpublished work, without statistical analysis, and as he did not indicate if water was available, these data cannot be evaluated adequately. Our objective was to investigate nitrogen excretion in a carnivorous species, the Turkey Vulture (Cathartes aura). Vultures feed on carrion which may be far from water. Thus, when feeding under natural conditions, they consume much nitrogen but are limited to that water available in the food. We compared the proportions of urinary N

Does Red-Cockaded Woodpecker Excavation of Resin Wells Increase Risk of Bark Beetle Infestation of Cavity Trees?

WEATHERHEAD, P. J., AND S. B. McRAE. 1990. Brood care in American Robins: Implications for mixed reproductive strategies by females. Animal Behaviour 39:1179-1188. WESTNEAT, D. F. 1987. Extrapair fertilizations in a predominantly monogamous bird: Genetic evidence. Animal Behaviour 35:877-886. WESTNEAT, D. F. 1990. Genetic parentage in the Indigo Bunting: A study using DNA fingerprinting. Behavioral Ecology and Sociobiology 27:6776. WESTNEAT, D. F., AND E. M. GRAY. 1998. Breeding synchrony and extrapair fertilizations in two populations of Red-winged Blackbirds. Behavioral Ecology 9:456-464. WESTNEAT, D. F., AND P. W. SHERMAN. 1997. Density and extra-pair fertilizations in birds: A comparative analysis. Behavioral Ecology and Sociobiology 41:205-215. WESTNEAT, D. F., P. W. SHERMAN, AND M. L. MORTON. 1990. The ecology and evolution of extra-pair copulations in birds. Current Ornithology 7: 331-369.

DO RED-COCKADED WOODPECKERS SELECT CAVITY TREES BASED ON CHEMICAL COMPOSITION OF PINE RESIN?

Abstract We examined resin chemistry of loblolly (Pinus taeda) and shortleaf (P. echinata) pines selected as cavity trees by Red-cockaded Woodpeckers (Picoides borealis) in eastern Texas. We sampled resin from (1) pines selected by Red-cockaded Woodpeckers that contained naturally excavated active cavities, (2) pines selected by forest biologists that contained artificially installed cavity inserts and were actively being used by Red-cockaded Woodpeckers, and (3) control pines of similar age and appearance to the active cavity trees. We hypothesized that if woodpeckers are inducing a change in resin chemistry by excavating resin wells, this change should appear in active cavity trees selected by woodpeckers and trees selected by biologists, but not in control pines. If woodpeckers are selecting pines that have specific resin chemistry, concentrations of some resin components in active cavity trees selected by the woodpeckers for natural cavity excavation should be different from both control pines and pines selected by biologists. A large diterpene acid peak containing an isopimaric- levopimaric-palustric methyl-ester mix in active natural cavity trees was approximately 20% greater than controls and 22% greater than trees with artificial cavities. None of the other eight resin chemicals differed among treatments. The activity of Red-cockaded Woodpeckers at resin wells did not appear to affect the composition of cavity tree resin. Woodpeckers, however, may select pines with specific resin chemistries for cavity trees.