Sitta Canadensis Research Articles

Bird communities reveal the ecological value of non-native Norway spruce plantations in Massachusetts, USA

The establishment of monoculture plantations of non-native tree species is a common practice for supplementing native timber stocks. Since native wildlife species may lack co-evolved traits needed to successfully exploit non-native tree species, non-native plantations are expected to provide inferior habitat for native biodiversity. However, some studies report that plantations may increase net biodiversity at the landscape scale by introducing novel habitats or supplementing existing natural forests. We used point counts to sample birds in 2016 and 2017 in mature Norway spruce (Picea abies) plantations in western Massachusetts, as well as representative native forest types, to evaluate bird use of these plantations relative to native forest types. Our findings showed that overall species richness for spruce plantations was similar to that of native forest habitats, and that several native conifer-dependent species (red-breasted nuthatch (Sitta canadensis), golden-crowned kinglet (Regulus satrapa), blackburnian warbler (Setophaga fusca), and brown creeper (Certhia americana) were significantly more abundant in spruce plantations relative to native deciduous, hemlock, and mixed stands. Bird species reported to associate with eastern hemlock (Tsuga canadensis), such as blue-headed vireo (Vireo solitarious) and black-throated green warbler (Setophaga virens), were observed using spruce plantations at similar levels as eastern hemlock stands. These results demonstrate that Norway spruce plantations can provide suitable habitat for native species associated with conifers, which is significant given projected continued decline of eastern hemlock in response to the hemlock wooly adelgid (Adelges tsugae). Although large-scale conversion of native forest to plantations would likely lead to a loss in biodiversity, land managers could be justified in allowing small-scale plantations to persist without suffering negative impacts to native biodiversity.

Woodpeckers and other excavators maintain the diversity of cavity-nesting vertebrates.

Woodpeckers and other excavators create most of the holes used by secondary cavity nesters (SCNs) in North American temperate mixedwood forests, but the degree to which excavators release SCNs from nest-site limitation is debated. Our goal was to quantify how excavators maintain the diversity and abundance of secondary cavity nesters in a temperate forest through the creation of tree cavities. We examined the short- and long-term (legacy) effects of excavators (principally woodpeckers, but also red-breasted nuthatches and black-capped chickadees) on forest biodiversity using longitudinal monitoring data (1,732 nest cavities, 25 sites, 16years) in British Columbia, Canada. Sites with higher densities of excavator nests had more cavities available, higher species richness of SCNs and higher nest density of SCNs, indicating the importance of a standing stock of cavities. Years with higher nesting densities of excavators were followed by years with higher SCN diversity, indicating that the creation of nesting opportunities through fresh excavation releases SCNs from community-wide nest-site limitation. We also show that excavators leave a 'legacy' of biodiversity (species richness and abundance) at a site by accumulating cavities at rates faster than they become unusable by decay or destruction. By quantifying site-level effects of cavity excavation on the SCN community, our study highlights the key role of excavators as ecosystem engineers that maintain forest wildlife biodiversity.

POECIVIRUS IS PRESENT IN INDIVIDUALS WITH BEAK DEFORMITIES IN SEVEN SPECIES OF NORTH AMERICAN BIRDS.

Avian keratin disorder (AKD), a disease of unknown etiology characterized by debilitating beak overgrowth, has increasingly affected wild bird populations since the 1990s. A novel picornavirus, poecivirus, is closely correlated with disease status in Black-capped Chickadees (Poecile atricapillus) in Alaska, US. However, our knowledge of the relationship between poecivirus and beak deformities in other species and other geographic areas remains limited. The growing geographic scope and number of species affected by AKD-like beak deformities require a better understanding of the causative agent to evaluate the population-level impacts of this epizootic. Here, we tested eight individuals from six avian species with AKD-consistent deformities for the presence of poecivirus: Mew Gull (Larus canus), Hairy Woodpecker (Picoides villosus), Black-billed Magpie (Pica hudsonia), American Crow (Corvus brachyrhynchos), Red-breasted Nuthatch (Sitta canadensis), and Blackpoll Warbler (Setophaga striata). The birds were sampled in Alaska and Maine (1999-2016). We used targeted PCR followed by Sanger sequencing to test for the presence of poecivirus in each specimen and to obtain viral genome sequence from virus-positive host individuals. We detected poecivirus in all individuals tested, but not in negative controls (water and tissue samples). Furthermore, we used unbiased metagenomic sequencing to test for the presence of other pathogens in six of these specimens (Hairy Woodpecker, two American Crows, two Red-breasted Nuthatches, Blackpoll Warbler). This analysis yielded additional viral sequences from several specimens, including the complete coding region of poecivirus from one Red-breasted Nuthatch, which we confirmed via targeted PCR followed by Sanger sequencing. This study demonstrates that poecivirus is present in individuals with AKD-consistent deformities from six avian species other than Black-capped Chickadee. While further investigation will be required to explore whether there exists a causal link between this virus and AKD, this study demonstrates that poecivirus is not geographically restricted to Alaska, but rather occurs elsewhere in North America.

Nuthatches vary their alarm calls based upon the source of the eavesdropped signals

Animal alarm calls can contain detailed information about a predator’s threat, and heterospecific eavesdropping on these signals creates vast communication networks. While eavesdropping is common, this indirect public information is often less reliable than direct predator observations. Red-breasted nuthatches (Sitta canadensis) eavesdrop on chickadee mobbing calls and vary their behaviour depending on the threat encoded in those calls. Whether nuthatches propagate this indirect information in their own calls remains unknown. Here we test whether nuthatches propagate direct (high and low threat raptor vocalizations) or indirect (high and low threat chickadee mobbing calls) information about predators differently. When receiving direct information, nuthatches vary their mobbing calls to reflect the predator’s threat. However, when nuthatches obtain indirect information, they produce calls with intermediate acoustic features, suggesting a more generic alarm signal. This suggests nuthatches are sensitive to the source and reliability of information and selectively propagate information in their own mobbing calls.

The importance of disturbance and forest structure to bird abundance in the Black Hills

AbstractMany North American birds associated with forest disturbances such as wildfire and mountain pine beetle (Dendroctonus ponderosae) outbreaks are declining in abundance. More information on relationships between avian abundance and forest structure and disturbance is needed to guide conservation and management. Our objective was to determine densities of American Three-toed Woodpecker (Picoides dorsalis), Black-backed Woodpecker (Picoides arcticus), Red-breasted Nuthatch (Sitta canadensis), Brown Creeper (Certhia americana), and White-winged Junco (Junco hyemalis aikeni) in relation to vegetation characteristics and disturbance at the point and landscape level in the Black Hills and Bear Lodge Mountains of South Dakota and Wyoming. We conducted 3 point counts from late March to late June 2015 and 2016 at more than 2,300 locations distributed across a gradient of forest structure and disturbance types. We estimated densities using 3-level hierarchical time-removal models that simultaneously estimated abundance, availability, and detection probability. Black-backed Woodpeckers were positively related to percent area in 1- to 3-year-old wildfires and Brown Creepers were positively associated with percent area in 4- to 5-year-old wildfires; however, Red-breasted Nuthatches were negatively related to percent area in 3- to 5-year-old wildfires. With the exception of American Three-toed Woodpeckers, species were positively related to percent cover of beetle-killed trees. Brown Creepers, White-winged Juncos, and Red-breasted Nuthatches had mixed responses to percent overstory canopy cover. White-winged Juncos also had a positive association with percent ground vegetation at the point and landscape level. Brown Creepers were strongly linked with spruce vegetation type. American Three-toed Woodpeckers, which are thought to occupy spruce forest in the Black Hills, did not show a strong relationship with any covariates. Maintaining some areas of natural disturbances along with heterogeneity of vegetation characteristics within stands and at the landscape scale will benefit the needs of a diverse bird community in the Black Hills.

Primer registro de bajapalos pecho canela (Sitta canadensis) en el bosque de Los Attenuatas, Baja California

El bajapalos pecho canela (Sitta canadensis) es una especie de distribución amplia en Estados Unidos y Canadá. No obstante,debido a irrupciones y vagabundeos, se ha registrado en Chihuahua, Sonora, Sinaloa, Baja California, Nuevo León y en el occidentede México (Jalisco y Colima). En Baja California existen cuatro registros: (1) Isla Guadalupe (población que se consideraextirpada desde 1995) (2), Sierra San Pedro Mártir (3), Sierra Juárez y (4) Santa Rosaliíta, los últimos dos registros son de hacemás de 20 años. Registramos por primera vez un bajapalos pecho canela macho adulto en el bosque de Los Attenuatas durantela temporada de invierno de 2015.

A decade of emerald ash borer effects on regional woodpecker and nuthatch populations

The emerald ash borer (EAB) Agrilus planipennis, first detected in 2002 in the vicinity of Detroit, Michigan, USA, has spread throughout much of eastern and midwestern North America as of 2016, resulting in widespread mortality of ash trees in the genus Fraxinus. We investigated the effects of this newly available, exotic food source on populations of six species of largely resident insectivorous birds, including five species of woodpeckers and white-breasted nuthatch (Sitta canadensis), using North American Breeding Bird Survey data for breeding season estimates and Audubon Christmas Bird Counts for winter season estimates. We found evidence for relatively modest and variable effects of EAB invasion on the populations of these birds during the breeding season, but highly significant numerical increases during the winter that in several cases appeared to be increasing as the EAB invasion has progressed. Our results confirm that the EAB invasion is resulting in increased populations of several insectivorous birds, primarily during the winter. They also suggest that the numerical response of woodpeckers to EAB may be such that avian predation, which represents a significant, and possibly the largest, morality factor affecting some EAB populations, may continue to increase and help control the EAB epidemic as the invasion continues.

Winter Movements of Sitta canadensis L. (Red-breasted Nuthatch) in New England and Beyond: A Multiple-scale Analysis

Abstract We analyzed 55 years of abundance data (1960–2014) for Sitta canadensis (Red-breasted Nuthatch) to seek patterns of winter irruptions on temporal and spatial scales. This species shows an erratic pattern of irruption into southerly areas from its northern breeding areas. Irruptions show a broad geographic synchrony. At the narrower level of the state or province and even more so at the level of individual counts, correlations of abundance in adjacent areas become weaker. The abundance of irruptive birds is best considered a mosaic. At the regional scale, correlations of Red-breasted Nuthatch abundance with irruptive northern finches that also depend on conifer seeds are weak to absent. The data suggest that birds irrupt because of failure of conifer seed production on the breeding grounds, not because the birds are seeking masting conifer stands to the south.

Novel Picornavirus Associated with Avian Keratin Disorder in Alaskan Birds.

ABSTRACTAvian keratin disorder (AKD), characterized by debilitating overgrowth of the avian beak, was first documented in black-capped chickadees (Poecile atricapillus) in Alaska. Subsequently, similar deformities have appeared in numerous species across continents. Despite the widespread distribution of this emerging pathology, the cause of AKD remains elusive. As a result, it is unknown whether suspected cases of AKD in the afflicted species are causally linked, and the impacts of this pathology at the population and community levels are difficult to evaluate. We applied unbiased, metagenomic next-generation sequencing to search for candidate pathogens in birds affected with AKD. We identified and sequenced the complete coding region of a novel picornavirus, which we are calling poecivirus. Subsequent screening of 19 AKD-affected black-capped chickadees and 9 control individuals for the presence of poecivirus revealed that 19/19 (100%) AKD-affected individuals were positive, while only 2/9 (22%) control individuals were infected with poecivirus. Two northwestern crows (Corvus caurinus) and two red-breasted nuthatches (Sitta canadensis) with AKD-consistent pathology also tested positive for poecivirus. We suggest that poecivirus is a candidate etiological agent of AKD.

Using automated recorders and occupancy models to monitor common forest birds across a large geographic region

ABSTRACTAutomated recorders and occupancy models can be used together to monitor population trends of multiple avian species across a large geographic region. Automated recorders are an attractive method for monitoring birds, because they leave a record that can be independently validated and multiple units can be programmed to repeatedly survey different locations at the same daily times. We assessed the use of automated recorders and single‐species, single‐season occupancy models to monitor common forest birds across a 5.4‐million‐ha region of northern California. Using a survey protocol of 5‐minute recordings at 3 times of the morning repeated over 3 consecutive days at 453 sites, we detected 32 species at >10% of these sites. Five of these species (Steller's jay [Cyanocitta stelleri], mountain chickadee [Poecile gambeli], red‐breasted nuthatch [Sitta canadensis], dark‐eyed junco [Junco hyemalis], and western tanager [Piranga ludoviciana]) were dominant with occupancies >0.5. We also modeled occupancy associations with elevation and canopy cover for brown creeper (Certhia americana), MacGillivray's warbler (Geothlypis tolmiei), and western tanager and found the environmental conditions at which occupancy was maximized differed by up to 399 m in elevation and 17.9% canopy cover for these species. Given a sampling effort of 100 new sites per year, we demonstrated 80% power (α = 0.1) to detect occupancy declines as small as 2.5% per year over 20 years for the 32 most common species. The effective radius of automated recorder surveys was approximately 50 m. In a field test, surveys conducted concurrently using automated recorders and point counts yielded similar occupancy estimates despite differences in detection probability. Our results suggest that automated recorders, used alone or in conjunction with point counts, can provide a practical means of monitoring common forest birds across a large geographic area. © 2014 The Wildlife Society.

Avian communities of managed and wilderness hemiboreal forests

We compared breeding bird communities of hemiboreal forests in multiple-use managed forests and relatively unmanaged wilderness forests in northern Minnesota. A total of 240 point-count locations, 120 in each of the managed and wilderness areas, were sampled three times across ten paired transects in 2010 and 2011. Transects were paired near lotic systems that cross each management type, with half of the points adjacent to (100m) or distant (400m) from the riparian corridor. Total number of individuals and species richness detected per count were higher within the unmanaged forest (F1,9=9.76, p=0.01; F1,9=11.17, p<0.01) and forest adjacent to the riparian corridor (F1,9=28.30, p<0.001; F1,9=42.12, p<0.001). These results were negatively correlated with increased area of regenerating forests (mainly from logging) within the managed forest and positively correlated with tree species richness and overstory height of forest stands within the wilderness forest. Of 35 species analyzed individually, Black-capped Chickadee (Poecile atricapillus), Brown Creeper (Certhia americana), Canada Warbler (Cardellina canadensis), Golden-crowned Kinglet (Regulus satrapa), Least Flycatcher (Empidonax minimus), Red-breasted Nuthatch (Sitta canadensis), Winter Wren (Troglodytes hiemalis), and Yellow-bellied Flycatcher (Empidonax flaviventris) were more common in the wilderness forest. Only the Mourning Warbler (Geothlypis philadelphia) and Chipping Sparrow (Spizella passerina) were more common in the managed forest. Species associated with mature or mixed forests tended to be found in the wilderness area at higher densities, but most species associated with early-successional habitats did not differ between the managed and wilderness landscapes. Results suggest that forests with natural disturbance and succession regimes provide habitat for a higher density and richness of bird species. Responses by breeding birds were similar in both management types regarding distance from riparian areas. To adequately provide for effective conservation of the avian community, forested regions should include wilderness forests.

Direct and indirect effects of an insect outbreak increase the reproductive output for an avian insectivore and nest‐cavity excavator, the red‐breasted nuthatch Sitta canadensis

Community‐wide food pulses may ameliorate food constraints but may also result in increased competition for other resources and predation rates. In cavity‐nesting vertebrate communities, where the availability of tree cavities can limit reproduction and the reuse of cavities can increase nest predation by squirrels, excavators may maximize their fecundity by creating new cavities in competitor‐ and predator‐rich habitats that undergo food pulses. The reproductive cost associated with excavation (i.e. increased energy allocation early in the breeding season that often delays laying and thereby reduces clutch size), may be reduced if food pulses allow for a longer breeding season and larger clutches. A large‐scale mountain pine beetle Dendroctonus ponderosae outbreak that occurred during our long‐term study (1995–2009) provided a natural food supplementation experiment across 27 sites in British Columbia, Canada. We examined the effects of a reduction in food constraints accompanied with increases in excavation rates, conspecific density and nest predation risk on the fecundity of a facultative excavator, the red‐breasted nuthatch Sitta canadensis. We found a total of 420 nests in tree cavities. Nuthatch clutch sizes ranged from two to nine eggs, and broods from one to nine fledglings per nest. Later clutches were larger at sites and in years with high beetle abundance (mean clutch size of six eggs did not decline later in the season), second broods were produced in outbreak years (usually only one nesting attempt/normal year), and the number of fledglings per successful nest increased with increasing beetle abundance and nuthatch densities, but declined with increased squirrel densities. Since fecundity did not differ between new and reused cavities, the costs and benefits of excavation versus cavity reuse may be neutralized for nuthatches during strong resource pulses. Overall, the beetle outbreak reduced food constraints for nuthatches and provided alternate food for nest predators, allowing increased annual fecundity.

A comparison of avian habitat in forest management plans produced under three different certification systems in Ontario, Canada

ABSTRACTConsiderable discussion and theoretical reviews of forest certification systems have been published that outline the potential impact of forest certification on biodiversity and wildlife habitat. Three common approaches to forest certification used in Canada include the Forest Stewardship Council, the Canadian Standards Association, and the Sustainable Forestry Initiative. In this study, I reviewed forest management plans in Ontario, Canada, and compared the plans' potential impact on habitat for 6 species of birds that use mature and older forests: pileated woodpecker (Dryocopus pileatus), ruby‐crowned kinglet (Regulus calendula), boreal chickadee (Poecile hudsonicus), black‐backed woodpecker (Picoides arcticus), great gray owl (Strix nebulosa), and red‐breasted nuthatch (Sitta canadensis). The purpose was to determine whether the different certification systems in use resulted in different impacts on avian habitat, and to compare certified forest management plans with plans prepared for un‐certified forest units. Based on 27 Forest Management Plans in Ontario, there seems to be little reason to believe that certified forests are more likely to protect and conserve habitat for these 6 bird species that use older forests than are forests that are not certified. © 2014 The Wildlife Society.

Effects of the emerald ash borer invasion on four species of birds

The emerald ash borer (EAB) Agrilus planipennis, first detected in 2002 in the vicinity of Detroit, Michigan, USA, is one of the most recent in a long list of introduced insect pests that have caused serious damage to North American forest trees, in this case ash trees in the genus Fraxinus. We used data from Project FeederWatch, a citizen science program focused on winter bird populations, to quantify the effects of EAB invasion on four species of resident, insectivorous birds known or likely to be EAB predators: three woodpecker species and the white- breasted nuthatch (Sitta canadensis). We compared relative numbers of birds within 50 km of the epicenter of the region where EAB was first detected, an area known to have suffered high ash tree mortality by 2008, to numbers 50-100 km from the epicenter and to control sites within 50 km of five comparable Mid- western cities where damage due to EAB has yet to be severe. We found evidence for significant effects on all four of the species in response to the EAB invasion in the highly impacted region, with red-bellied wood- peckers (Melanerpes carolinus) and white-breasted nuthatches showing numerical increases while downy woodpeckers (Picoides pubescens) and hairy wood- peckers (Picoides villosus) initially declined but exhibited at least temporary increases several years later. Temporal correlation analyses failed to provide support for immigration being a major cause of the elevated numbers in the highly impacted area, and thus these results are consistent with the hypothesis that increases were due to enhanced survival and/or repro- duction associated with the EAB invasion within the highly impacted area. Results suggest that the contin- uing invasion of EAB into new areas is likely to significantly alter avian communities, although not always in ways that will be easy to predict.

Red-breasted nuthatches (Sitta canadensis) increase cavity excavation in response to a mountain pine beetle (Dendroctonus ponderosae) outbreak

In cavity-nesting vertebrate species, reproduction is limited by the production and availability of tree cavities. Excavating species may create new cavities to exploit food resource pulses in novel habitats, but availability of nesting resources may be constrained with increases in population densities. Over a 15-y period, we monitored the reproduction of cavity nesters and a large-scale mountain pine beetle (Dendroctonus ponderosae) outbreak that killed all mature lodgepole pine (Pinus contorta var. latifolia), at 30 mixed coniferous—deciduous stands in interior British Columbia, Canada. We examined how the probability of excavation of a bark insectivorous, facultative cavity excavator, the red-breasted nuthatch (Sitta canadensis), was influenced by mountain pine beetle abundance and changes in population densities of conspecific individuals and a nest predator, red squirrel (Tamiasciurus hudsonicus). Nuthatches always chose trembling aspen (Populus tremuloides) for nesting regardless of densities of nuthatch nests and availability of beetle-decayed pine as alternate nest trees. The number of nuthatch nests increased in years of increasing densities of beetle-infected pine, and the proportion of freshly excavated nests varied annually, increasing with the beetle outbreak from 26% of all cavities used in 2001 to 70% in 2002 and then declining after the outbreak to 17% in 2009. For each unit increase in densities per hectare of both nuthatches and beetle-infected pine trees, the odds that individuals would excavate a new cavity rather than use an existing cavity increased by 147 times. With each 10 m farther into the coniferous forest interior, the odds of excavation increased by 10 times. These results suggest that facultative excavators are able to exploit novel habitats during insect outbreaks by adjusting their nest-site selection patterns and increasing excavation, but that resource pulses may lead to limitation of nesting resources.

Insect outbreaks increase populations and facilitate reproduction in a cavity‐dependent songbird, the Mountain Chickadee Poecile gambeli

Large‐scale insect outbreaks, typical of temperate ecosystems, may increase food availability and influence species interactions in insectivorous bird communities. We assessed how population densities of a secondary cavity nester, the Mountain Chickadee Poecile gambeli, varied with densities of avian cavity excavators, potential competitors and nest predators, during two large‐scale insect outbreaks of Western Spruce Budworm Choristoneura occidentalis and Mountain Pine Beetle Dendroctonus ponderosae. At the regional level, Mountain Chickadee densities doubled with increases in budworm and beetle availability, then declined with decreases in beetle availability, despite high budworm supply. At the site level, densities of excavators were the best predictor of site‐level variation in Chickadee densities in the following year. During and after the beetle outbreak, Mountain Chickadees used more cavities excavated by Red‐breasted Nuthatches Sitta canadensis and Downy Woodpeckers Picoides pubescens, both of which are bark insectivores that increased in densities concomitantly with the beetle outbreak and whose foraging activities may have facilitated the Mountain Chickadees' access to bark beetles. Thus, Mountain Chickadees showed a numerical response to the food pulse at the regional level, but a functional response to the pulse of nesting cavities at the site level. Plasticity in resource selection and heterospecific attraction may allow Mountain Chickadees to respond to resource pulses in highly variable environments.

Foraging Patterns of Cavity-Nesting Birds in Fire-Suppressed and Prescribe-burned Ponderosa Pine Forests in Montana

Fuel-reduction/forest restoration treatments that consist of thinning followed by prescribed burning are becoming increasingly important land management actions that likely affect various wildlife species. To assess potential effects on bark-gleaning birds, we compared the foraging patterns of five cavity-nesting species in thinned and burned ponderosa pine (Pinus ponderosa) forest sites and control sites. We recorded foraging behavior, location on forage tree, and tree characteristics that may be important in the selection of foraging substrates. Foraging surveys were conducted on three replicate 20-ha thinned/burned plots located within larger treatments that ranged from 60 - 250 ha, paired with three replicate control plots. Red-breasted Nuthatches (Sitta canadensis) foraged more often in control sites. Mountain Chickadees (Poecile gambeli) foraged at similar rates on both treatment types. Black-backed Woodpeckers (Picoides arcticus), Hairy Woodpeckers (P. villosus) and White-breasted Nuthatches (Sitta carolinensis) foraged almost exclusively in thinned/burned sites. Overall, all species selectively foraged on larger diameter trees. In control sites, Red-breasted Nuthatches selected larger ponderosa pine trees and Mountain Chickadees selected larger, live trees. In thinned/burned sites, Red-breasted Nuthatches selected larger, live trees, Mountain Chickadees selected larger trees with more canopy connections, Black-backed Woodpeckers selected trees with beetle evidence present and Hairy Woodpeckers selected recently dead trees. These results suggest fuel reduction/forest restoration treatments in dry ponderosa pine forests may be compatible with providing foraging substrates for cavity-nesting species often present in post-fire habitats.

Scale-dependent Response by Breeding Songbirds to Residential Development Along Lake Superior

We examined the influence of shoreline residential development on breeding bird communities along forested portions of Lake Superior and hypothesized that anthropogenic changes related to housing development would alter bird community structure compared to areas without human development. We used point counts to compare relative abundance of bird species in relation to residential development at coarse (along 1 km shoreline stretches with and without housing/cottage development) and fine (developed and undeveloped sides of a shoreline access road) spatial scales during the 2005 breeding season. More species had development related differences in abundance at the finer-scale analysis than at the coarse scale. American Crows (Corvus brachyrhynchos) and American Robins (Turdus migratorius) were more abundant on the developed, shoreline side of shoreline access roads. Red-breasted Nuthatches (Sitta canadensis), Black-throated Green Warblers (Dendroica virens), and Red-eyed Vireos (Vireo olivaceus) were more abundant on the undeveloped, inland side of shoreline access roads. Several species were detected exclusively in developed or undeveloped forest areas. The pattern of development-related differences in relative abundance of bird species depended on the scale at which data were analyzed, suggesting that many species may respond to habitat differences within the 100 m scale quite distinct from how they respond to differences at the scale of thousands of meters.

Microhabitat Selection of Bark-Foraging Birds in Response to Fire and Fire Surrogate Treatments

Abstract We examined the short-term response of the bark-foraging bird community to mechanical thinning, prescribed fire, and thinning/prescribed fire combination treatments designed to reduce fuel loads at study sites throughout the continental United States as part of the national Fire and Fire Surrogate (FFS) project. We modeled the effects of study site, treatment, treatment category, and time since treatment on the foraging encounter rate of four individual species (red-breasted nuthatch [Sitta canadensis], mountain chickadee [Poecile gambeli], hairy woodpecker [Picoides villosus], and brown creeper [Certhia americana]) and assessed the relative importance of several tree and snag characteristics in the selection of foraging trees by these same species. The foraging encounter rate of all four species responded inconsistently across both treatment categories and study sites. Substrate diameter was the strongest and most consistent characteristic positively influencing the selection of foraging habitat structures for all species across all treatment categories. Other influential variables included the presence of bark beetles for red-breasted nuthatches, hairy woodpeckers, and brown creepers in control and burn-only treatment areas and tree species for brown creepers in burn-only and thin-only treatment areas. Although this study did not detect any major negative treatment response by any species, our results suggest that there is substantial variability in the reaction of this particular bird community to fuel reduction treatments and that managers may need to evaluate the effects of these treatments on a site-by-site and species-by-species basis.

Short-Term Effects of Thinning and Burning Restoration Treatments on Avian Community Composition, Density, and Nest Survival in the Eastern Cascades Dry Forests, Washington

Abstract We monitored the short-term (&amp;lt;3 years) response of land birds to restoration treatments (thin, burn, and thin-burn) in dry forests located on the eastern slope of the Cascade Range in Washington. Overall avian community composition did not change among the treatments. However, individual species responses varied with the chipping sparrow showing lower density in treatments, whereas hermit thrush, mountain chickadee, white-headed woodpecker, western bluebird, American crow, and common raven increased in treatment units. Daily survival rates of nesting guilds were similar in treated versus control stands; however, burn-only showed lower daily survival rates compared with other treatments. Additional research is needed to validate this result. Cavity-nesters (mountain chickadee, red-breasted nuthatch, and house wren) and foliage-nesters (chipping sparrow) used trees that were larger in diameter than available regardless of the treatment. Our results, in combination with other results from this study area, provide important implications for managers: (1) thin-burn treatments were effective at restoring habitat for several avian focal species; (2) spring burn treatments should be carefully designed to achieve desired restoration objectives; (3) large trees provide important habitat functions and are a key component for maintaining or restoring the viability of focal avian species; and (4) additional research is needed to better understand the effects of spring burning and the long-term effects of dry forest restoration treatments.