Total Bird Density Research Articles

Pollution impacts on bird population density and species diversity at four non-ferrous smelter sites

Non-ferrous smelters pose a potential hazard for breeding bird populations, but comprehensive analyses of the impacts on bird population densities around smelter sites are currently lacking. We measured with point counts bird population densities around four smelter sites in Russia (Monchegorsk, Karabash and Revda) and Finland (Harjavalta) to explore the relationships between bird population density/species diversity and exposure level quantified by the potentially bioavailable copper concentrations in forest litter. Total bird densities, bird biomasses and species diversities decreased in the vicinity of all three Russian smelters. In Harjavalta, there were no pollution-related trends in total bird density or biomass, although species diversity (species number and Shannon’s index) decreased towards the pollution source. In general, the four smelters showed negative effects on bird populations in decreasing order of impact as follows: Monchegorsk>Karabash>Revda>Harjavalta, reflecting the amount of current and past emissions and consequent habitat change at each site. Our results suggest that around copper–nickel and copper smelters the pollution impact on bird diversity is accelerated when the litter copper level exceeds 1000μg/g. However, even though bird densities and diversities reflected the exposure levels in our study, they were not associated with litter copper concentrations in a strictly dose-dependent manner, indicating that copper itself is not a primary cause for the changes in bird communities, but rather the combined effect of multiple pollutants on birds and especially on the resources necessary for breeding, such as food and suitable habitat.

How would size, age, human disturbance, and vegetation structure affect bird communities of urban parks in different seasons?

Parks are diversity hotspots in cities, and are generalized isolated “islands” in urban landscapes. However, there is a paucity of information on the avian community structure of urban parks in big cities in Southeast Asia, including Hong Kong which has more than 7 million people. This study therefore aimed to assess the influences of park attributes, human disturbance, and vegetation structure on species richness, diversity, total density, and species groups of breeding and wintering bird communities in Hong Kong. Bird communities of 30 parks were censused four times each season in 2010–2011 using point counting. Species richness and diversity were affected by park size in both seasons, and larger parks supported more species and higher diversity. In addition, species richness of wintering season was negatively affected by visitor rate. Total bird density increased with visitor rate, but only in the breeding season. Noise did not have significant impacts on species richness, diversity, and total density. Regarding the responses of species groups, number of resident species increased with park size in both seasons. Migrants, insectivores, and insectivore–frugivores were positively affected by park size, but negatively by visitor rate in the wintering season. However, omnivores in the breeding season increased with both park size and visitor rate. Granivores was the only feeding guild which was positively affected by noise and negatively by foliage height diversity in the wintering season. In conclusion, park size and visitor rate affected bird community structure, and different species groups had different responses to habitat factors in the two seasons.

Succession of bird communities in young temperate rainforests following thinning

We repeated bird and vegetation surveys in 1991–1992 and 2005–2006 among young managed stands and old-growth forests in southeast Alaska to evaluate whether pre-commercial thinning of managed stands influenced the bird community. We compared decadal changes in bird densities and forest vegetation among 3 stand types: managed stands originating from clearcuts 35 years ago that were left untreated (unthinned), managed stands thinned at uniform spacing (thinned), and old growth with no prior timber harvest. We did not detect differences in decadal trends in avian densities between thinned and unthinned stands for 15 of 16 common bird species using a repeated-measures design. Thinning did not result in greater recruitment of overstory-nesting species as predicted. This was likely because of 1) similar increases in tree heights ( = 9–10 m) and canopy cover ( = 29–43%) between unthinned and thinned stands across decades and 2) the relatively young successional stage of these stands, which had only begun to recruit medium and large size conifers (dbh ≥ 36 cm). Decadal trends in densities of most (88%) understory-nesting bird species did not differ between thinned and unthinned stands. Shrub cover decreased by 22% and 31% across decades in thinned and unthinned stands, respectively. Bird community composition in managed stands reflected the general decadal changes in forest vegetation with a shift in dominance from understory species in the early 1990s (80–85% of total bird density) to an equal abundance of understory (45–54%) and overstory species in the mid-2000s. The latter was more similar to old-growth stands, which were dominated by overstory species (67–71%). Overstory-nesting birds in old growth increased in density by 49% across decades. Densities of cavity-nesting species remained unchanged in managed stands and less than densities in old growth across decades, possibly because of a lack of large trees and snags for nest sites. Overall, thinning of clearcut stands, the primary silvicultural system in the region, had few measurable benefits to birds nearly 20 years after treatment. Monitoring over the 70–100-year harvest rotation may be necessary to fully test whether thinning accelerates succession of bird communities in clearcut stands. However, partial harvests that retain large trees and snags should also be explored as alternatives to better maintain late-succession avifauna throughout the harvest rotation in southeast Alaska. © 2012 The Wildlife Society.

The efficacy of common species as indicators: avian responses to disturbance in British Columbia, Canada

Common species can be major drivers of species richness patterns and make major contributions to biomass and ecosystem function, and thus should be important targets for conservation efforts. However, it is unclear how common species respond to disturbance, because the underlying reasons for their commonness may buffer or amplify their responses to disturbance. To assess how well common species reflect changes in their community (and thus function as indicator species), we studied 58 bird species in 19 mixed conifer patches in northern British Columbia, Canada, between 1998 and 2010. During this time period two disturbance events occurred, stand level timber harvest and a regional-scale bark beetle outbreak. We examined relationships among densities of individual species, total bird density and overall species richness, correlations in abundance among species, and responses to disturbance events. We found three broad patterns. First, densities of common species corresponded more strongly with changes in total bird density and overall species richness than rare species. These patterns were non-linear and species with intermediate-high commonness showed similar or better correspondence than the most common species. Second, common species tended to be more strongly correlated with abundances of all other species in the community than less-common species, although on average correlations among species were weak. Third, ecological traits (foraging guild, migratory status) were better predictors of responses to disturbance than species commonness. These results suggest that common species can collectively be used to reflect changes in the overall community, but that whenever possible monitoring programs should be extended to include species of intermediate-high commonness and representatives from different ecological guilds.

Interspecific Variation in Habitat Preferences of Grassland Birds Wintering in Southern Pine Savannas

We studied wintering grassland bird communities in De Soto National Forest in southern Mississippi, USA to assess differences in bird communities and vegetation structure among different stand types. We also examined which vegetation structure and plant species predicted occurrence of Bachman's Sparrow (Peucaea aestivalis), Henslow's Sparrow (Ammodramus henslowii), and Sedge Wren (Cistothorus platensis). Bachman's Sparrows occurred only in uplands ( = 0.5 birds/ha) and stands managed for Red-cockaded Woodpeckers (Picoides borealis; = 0.9 birds/ha), Henslow's Sparrows occurred only in bogs ( = 3.8 birds/ha) and stands managed for Red-cockaded Woodpeckers ( = 2.1 birds/ha), while Sedge Wrens occurred in all stand types ( = 0.1–0.3 birds/ha). There were no significant differences among stand types in total bird densities for all three species combined. Dense, spatially uniform herbaceous cover and cover of Scleria muhlenbergii, a preferred food item in bogs, best predicted Henslow's Sparrow occurrence (39% s2 explained). Increased woody understory vegetation and decreased tree density best predicted Sedge Wren occurrence (17% s2 explained). Management for Henslow's Sparrows should focus on small-scale herbaceous ground-layer restoration in bogs. Bachman's Sparrows will respond more to thinning dense upland stands. Sedge Wrens and Bachman's Sparrows benefit from Red-cockaded Woodpecker management, whereas Henslow's Sparrow use of woodpecker stands is ephemeral.

Sea to sky: impacts of residual salmon-derived nutrients on estuarine breeding bird communities

Pacific salmon (Oncorhynchus spp.) returning to streams around the North Pacific Rim provide a nutrient subsidy to these ecosystems. While many species of animals feed directly on salmon carcasses each autumn, salmon-derived nutrients can also be stored in coastal habitats throughout the year. The effects of this storage legacy on vertebrates in other seasons are not well understood, especially in estuaries, which can receive a large portion of post-spawning salmon nutrients. We examine the effects of residual salmon-derived nutrients, forest habitats and landscape features on summer breeding birds in estuary forests. We compared models containing environmental variables and combined chum (Oncorhynchus keta) and pink (Oncorhynchus gorbuscha) salmon biomass to test predictions concerning bird density and diversity. We discovered that total bird, insectivore, golden-crowned kinglet and Pacific wren densities and Shannon's diversity in the summer were strongly predicted by salmon biomass in the autumn. For most metrics, this relationship approaches an asymptote beyond 40 000 kg of salmon biomass. Foliage height diversity, watershed catchment area and estuary area were also important predictors of avian communities. Our study suggests that the legacy of salmon nutrients influences breeding bird density and diversity in estuaries that vary across a wide gradient of spawning salmon biomass.

Influence of Spring Weather Conditions on Breeding Bird Densities in GTNP

The thaw came very late to Jackson Hole in 2011, with snow melt-out on May 15th. This year shares with 2008 and 2010 the claim of the latest spring over recent decades. The spring snow melt-out is a function of both accumulated snowfall and spring temperatures. A second measure of the advent of spring is the accumulation of growing degree-days (GDD); GDD finally exceeded 225 (°F; 125 °C) on June 23rd, that value being a predictor of 90% leaf-out in aspens. As is usual in late years, overall species richness and total bird density were generally lower across most park habitats. In particular, the foliage insectivores of the deciduous habitats, such as warblers and vireos in willows, aspens and cottonwoods, were much reduced in density (by as much as 50%). Sagebrush habitats, where snow persists longer in late springs and where most species feed on the ground early in the breeding season, were the most impoverished. In two such monitoring sites, #4 (Jackson Lake Junction Grass-sage) and #6 (Airport Sage), there were 1/4 to 1/3 fewer species present respectively, and bird densities were reduced to 43% and 39% of long-term averages for the sites.

Bird community response to filter strips in Maryland

AbstractFilter strips are strips of herbaceous vegetation planted along agricultural field margins adjacent to streams or wetlands and are designed to intercept sediment, nutrients, and agrichemicals. Roughly 16,000 ha of filter strips have been established in Maryland through the United States Department of Agriculture's Conservation Reserve Enhancement Program. Filter strips often represent the only uncultivated herbaceous areas on farmland in Maryland and therefore may be important habitat for early‐successional bird species. Most filter strips in Maryland are planted to either native warm‐season grasses or cool‐season grasses and range in width from 10.7 m to 91.4 m. From 2004 to 2007 we studied the breeding and wintering bird communities in filter strips adjacent to wooded edges and non‐buffered field edges and the effect that grass type and width of filter strips had on bird community composition. We used 5 bird community metrics (total bird density, species richness, scrub‐shrub bird density, grassland bird density, and total avian conservation value), species‐specific densities, nest densities, and nest survival estimates to assess the habitat value of filter strips for birds. Breeding and wintering bird community metrics were greater in filter strips than in non‐buffered field edges but did not differ between cool‐season and warm‐season grass filter strips. Most breeding bird community metrics were negatively related to the percent cover of orchardgrass (Dactylis glomerata) in ≥1 yr. Breeding bird density was greater in narrow (<30 m) compared to wide (>60 m) filter strips. Our results suggest that narrow filter strips adjacent to wooded edges can provide habitat for many bird species but that wide filter strips provide better habitat for grassland birds, particularly obligate grassland species. If bird conservation is an objective, avoid planting orchardgrass in filter strips and reduce or eliminate orchardgrass from filter strips through management practices. © 2011 The Wildlife Society.

Density and Diversity of Water Birds and Terrestrial Birds at Paya Indah Wetland Reserve, Selangor Peninsular Malaysia

The main objectives of this study was to determine and compare the density and diversity of water birds and terrestrial birds using distance sampling point count method at Paya Indah Wetland Reserve, Selangor Peninsular Malaysia. A total of 13872 bird individuals from 100 bird species were recorded in the wetland reserve. Out of the total, 25 (22.26% of all detections) and 75 (77.74% of all detections) bird species belong to water birds and terrestrial birds respectively. The results showed that total bird density of the wetland reserve is 83.92±4.53 birds ha-1 and ranged from 75.40-93.41 birds ha-1 (95% confidence interval). The terrestrial birds have higher density (70.26±4.48 birds ha-1) as compared to water birds (13.09±1.78 birds ha-1). The highest water bird density was recorded for Purple Swamphen (5.05±0.89 birds ha-1) and the lowest was Ballion's Crake (0.31±0.13 birds ha-1). The highest terrestrial bird density was recorded for Yellow-vented Bulbul (12.97±1.05 birds ha-1) and the lowest was Ashy Minivet (0.31±0.18 birds ha-1). The highest species diversity i.e. Shannon’s index (N1 = 20.83), species richness i.e. Margalef’s index (R1 = 7.97) and species evenness, i.e., McIntosh’s index (E = 0.73) was recorded in terrestrial birds. This study indicated that Paya Indah Wetland Reserve is a highly important habitat and provides diverse food, shelter, nesting and roosting sites for water birds as well as terrestrial birds.

Breeding bird communities of second‐rotation plantations at different stages of the forest cycle

Capsule Early stages of the plantation forest cycle have distinct bird communities and bird density was significantly higher in the second rotation than in the first for a given age class. Aims To characterize the bird communities in Irish second-rotation plantations and to compare them with those of first-rotation plantations. Methods Point counts were used to survey 20 plantation forests in four age classes (Pre-thicket; Thicket; Mid‐rotation; and Mature) in the breeding season of 2007. distance software was used to generate bird densities. Ordination, indicator species analysis, and glm were used to analyse the bird communities. Results Bird communities of Pre‐thicket and, to a lesser extent, Thicket age classes were distinct from those of more mature forests. Bird communities of Mid‐rotation and Mature age classes were indistinguishable from each other and were therefore combined into a single age class (Closed canopy). Pre‐thicket held significantly lower total bird density, but significantly higher migrant bird density, than this Closed canopy age class. Bird density was significantly higher in the second rotation in all age classes except for Pre‐thicket, but migrant density was significantly higher in Pre‐thicket in the second rotation. There was no difference in species richness between the first and second rotation. Conclusions Differences between rotations are probably due to changes in vegetation structure, and the increase in second‐rotation forests in Ireland is likely to be a positive development for bird communities. Especially encouraging is the higher migrant bird density in second‐rotation Pre‐thicket, as some of these species are in decline throughout Europe. However, the largest differences in population density between rotations were exhibited by common species and such species will likely benefit most from future increases in the area of second‐rotation plantation forests.

Habitat associations and breeding bird community composition within the city of Bristol, UK

Capsule Different urban breeding bird communities are associated with different habitat types, but, although community species diversity varies significantly, total bird density does not. Aims To investigate the association between breeding bird communities and habitats within Bristol, UK and how these communities vary in terms of species diversity and total bird abundance. Methods Breeding density data for 70 species in the metropolitan area of Bristol, UK were subjected to de‐trended correspondence analysis to identify the number of different communities present and their indicator species. These data were then used to identify patterns of habitat association with each community and differences in species richness and total bird density. Results Three communities were identified: a rural community associated with woodland, managed grassland and inland water; a suburban community associated with buildings and residential gardens; and an intermediate community that shared some of these habitat characteristics. Species richness, but not total bird abundance, was lowest in the suburban community. Conclusion The diversity of species in urban areas appears to be most dependent upon the availability of patches of natural and semi‐natural habitats. Residential gardens support fewer species, but those species that are present may be found at high densities.

Are bird density, species richness and community structure similar between native woodlands and non-native plantations in an area with a generalist bird fauna?

This study compared the bird assemblages of native semi-natural woodlands and non-native Sitka spruce (Picea sitchensis) plantations in Ireland to identify what vegetation variables most influenced birds and to identify management targets in plantations to maximise future bird conservation. Point counts were conducted in 10 Oak (Quercus spp.) and 10 Ash (Fraxinus excelsior) native woodlands and in five Mid-rotation (20–30 years old) and five Mature (30–50 years old) Sitka spruce plantations. Ordination was used to characterise woodland types according to their constituent bird species. Total bird density (calculated using Distance software) and species richness were assessed for the different woodland types. Oak and Ash woodland bird assemblages were separated from Mid-rotation and Mature plantations by the ordination. There was no difference in total bird density between any of the woodland types. Oak woodlands had significantly higher species richness than either Mid-rotation or Mature Sitka spruce plantations. Ash had higher species richness than Mature Sitka spruce plantations. Understorey vegetation was negatively associated with total bird density, which also varied with survey year. Understorey vegetation was positively associated with species richness. Reasons for the relationships between vegetation and bird assemblages are discussed. Management should seek to increase shrub and understorey vegetation in the Mid-rotation phase to improve the contribution of plantations to bird conservation.

Farmland as stopover habitat for migrating birds - effects of organic farming and landscape structure

Agricultural intensification in Europe has affected farmland bird populations negatively, both during summer and winter. Although the migratory period poses separate challenges on birds than breeding and wintering, the consequences of farming practices for birds during migration remain poorly investigated. We monitored abundance and species richness of migratory birds in autumn at matched pairs of organic and conventional farms situated either in intensively farmed open plains (homogeneous landscapes) or in small-scale farming landscapes (heterogeneous landscapes) in southern Sweden. Total bird density did not differ between landscape types but was marginally higher on organic compared to conventional farms. When including taxonomic status in the model (passerines vs non-passerines), we found significantly more birds on organic farms, and more non-passerines in the homogeneous landscapes. The effect of farming practice and landscape type on density differed between functional groups. Omnivore density was higher in the homogeneous landscapes, and invertebrate feeders were marginally more abundant on organic farms. The effects of farming practice on the overall species richness and on the density of granivorous birds were landscape dependent. In the homogeneous landscapes, organic farms held a higher number of species and density of granivorous birds than conventional farms, but there was no such difference in the heterogeneous landscapes. Thus, organic farming can enhance abundance and species richness of farmland birds during migration, but the effect differs between landscape types and species. The effectiveness of organic farming was highest in the homogeneous landscape making it important to promote organic farming there. However, for some species during migration, increased heterogeneity in homogeneous landscapes may have negative effects. We propose that migratory bird diversity in homogeneous landscapes may be best preserved by keeping the landscape open, but that a reduced agricultural intensity, such as organic farming, should be encouraged.

Breeding bird response to long-term wastewater discharge in a northern Michigan peatland

Researchers have monitored avian use of the Houghton Lake Sewer Authority wastewater treatment wetland and a nearby reference site from 1979 to 2007. Morning breeding bird surveys were conducted annually using 100-m belt transects. Annual species richness declined over the 29 years at the treatment site, but remained stable at the reference area. In a 12-year comparison of bird use of treated and reference wetland types, total bird density was highest in treated wetland consisting of cattail and cattail–wet meadow vegetation and lowest on leatherleaf and wet meadow reference types. Although species richness was highest in scrub-shrub wetland, treated wetland containing cattail marsh had significantly higher mean richness than types similar to pretreatment conditions (leatherleaf and wet meadow). Shannon diversity values in treated types dominated by cattail were similar to those in scrub-shrub wetland, but significantly higher than means observed in leatherleaf and wet meadow. Densities of Mallard, Green-winged teal, Virginia Rail, Sora, Wilson's Snipe, Marsh Wren, Swamp Sparrow, Red-winged Blackbird, and Common Grackle were highest at the treatment site in types containing cattail. Highest mean densities of Sedge Wren, Savannah Sparrow, and Northern Harrier occurred in wet meadow or leatherleaf types representative of pretreatment conditions.

Experimental evidence for the use of density based interspecific social information in forest birds

Reproductive success and habitat preference are generally assumed to be negatively associated with densities of con‐ and heterospecific competitors. However, recent theoretical studies have suggested that in some cases habitat preference may have a nonlinear unimodal function in relation to con‐ or heterospecific competitor densities – intermediate densities being preferred. Such a pattern is expected if con‐ or heterospecific densities are used as a proximate cue in habitat selection, which may produce benefits by reducing searching costs and providing information about current habitat quality and costs of competition. At low density the use of such cues, and hence habitat selection, are hampered, whereas at high density costs of competition exceed the benefits of using cues, leading to avoidance. Here, we tested this hypothesis by examining whether arboreal migratory birds use the density of resident titmice (Parusspp.) in habitat selection decisions. Many migrants and titmice species share similar resource needs making titmice density a reliable source of information for migrants. At the scale of habitat patches, we experimentally created a range of titmice densities from low to very high and subsequently measured the density response of migrants. In contrast to the unimodal habitat preference hypothesis, the average species number and total density of migratory birds were positively and linearly correlated with manipulated titmice density. Thus, migrants probably use titmice density as a relative indicator of habitat quality (abundance or quality of food) because foliage gleaners that share similar food resource with titmice, but not ground foragers, showed a positive association with manipulated titmice density. These results emphasize the positive effect of interspecific social information on habitat choice decisions and diversity of migratory bird community.

Patrones de distribución, abundancia y riqueza de especies de la avifauna terrestre de la isla de La Palma (islas Canarias)

We estimate the population size and density, habitat preferences, habitat breadth and probable population trends in the last 25-15 years of the diurnal terrestrial bird species breeding in La Palma island (Canary islands). Data were obtained in a large extensive census program carried out during the 2007 nesting period using line transects that allowed detectability estimations. We also explored patterns of species richness both at inter-habitat and local scale. Local species richness (species per 0.5 km transects) showed an important geographical component, increasing from south to north, from west to east, and reaching maximum values at altitudes around 600-1,000 m a.s.l. It was also positively related to vegetation development (specially in the herbaceous and shrub layer), and negatively associated with urbanization and agriculture. Total bird density reached the highest figures in the ‘monteverde’ (laurel and heath forests ca. 650 aves/km2), and in the transition pinewoods-laurel forests (509 aves/km2), while the lowest figures were recorded in high altitude shrublands (153 aves/km2) and recent lava fields (58 aves/km2). The bird species with lower population sizes are Falco [peregrinus] pelegrinoides, Burhinus oedicnemus distinctus, Upupa epops, Carduelis carduelis, Miliaria calandra and Petronia petronia, while the last five species have undergone more negative population trends in the last 15-25 years.

The effects of habitat heterogeneity on avian density and richness in soybean fields in Entre Ríos, Argentina

Birds play several roles in agricultural lands and respond to habitat heterogeneity within the agricultural landscape. Agricultural intensification in Argentina has increased the sown area, mainly with soybean, fragmenting landscapes in the pampas and mesopotamic region. In Entre Ríos Province, the original Espinal forest has been fragmented, leaving remnant patches of natural vegetation, in cases modified by cattle grazing. These changes represent a potential threat for avian conservation. In Entre Ríos, terraces may be a useful habitat in maintaining avian diversity, similar to other non-cropped linear habitats in agricultural landscapes. We tested the hypothesis that habitat heterogeneity created by terraces would maintain higher species richness and densities of avian species that use original or modified forests within cropped areas compared to fields without terraces. The study was carried out in soybean fields with an adjacent forest and either herbaceous, shrub or no terraces in two periods (March-April 2004). Birds were surveyed using line transects in field interior and edge, and observations were carried out in one forest remnant adjoining each field. Most bird species recorded in soybean fields were insectivorous or consume invertebrates during the breeding season. Species richness, total bird density and the density of granivores, insectivores and omnivores were higher in fields with terraces than in fields without terraces. Moreover, shrub terraces had higher effect on species richness and bird density than herbaceous terraces. Our results suggest that terraces may serve as a possible tool for maintaining avian diversity in agroecosystems in Entre Ríos.

Winter and Early Spring Bird Communities in Grasslands, Shrubsteppe, and Juniper Woodlands in Central Oregon

We compared winter (December, January, and February) and early spring (March and April) bird communities among 4 successional stages that included grassland, shrubsteppe, juniper-shrubsteppe, and old-growth juniper woodland in central Oregon. Birds were surveyed monthly from December through April in 1998/1999 and 1999/2000 using the point count method to estimate relative abundance of birds (individuals · transect−1year−1). We used distance sampling to correct for potential bias in estimating abundance and density among successional stages. A total of 4513 birds (32 species) were detected. Relative abundance of total birds (all species combined) was similar in the juniper-shrubsteppe and old-growth woodland (48.7 and 48.9 individuals · transect−1, respectively) but 6 times greater than in the grassland and shrubsteppe (8.0 and 7.7 individuals · transect−1, respectively) during the 5-month period. Total density of birds was greater in old-growth juniper woodland and juniper-shrubsteppe than in grassland or shrub-steppe. However, median bird species richness in 1998/1999 was highest in grassland and lowest both in shrubsteppe and juniper-shrubsteppe, and in 1999/2000 it was highest in shrubsteppe and lowest in juniper-shrubsteppe and old-growth juniper woodland. American Robins and Townsend's Solitaires were the most abundant species in juniper-shrubsteppe and old-growth juniper woodland during the winter months. Sage Sparrows and Horned Larks were the most abundant species in shrubsteppe during winter, and Horned Larks were most abundant in grasslands during the early spring transition period prior to nesting. Our results indicate that a different suite of species use these successional stages during the nonbreeding season. If avifauna conservation is a part of long-term management goals, a broad range of successional stages should be maintained on the landscape to provide habitat for a variety of avian species throughout the year.

Short‐Term Effects of Fire and Other Fuel Reduction Treatments on Breeding Birds in a Southern Appalachian Upland Hardwood Forest

Abstract: We compared the effects of 3 fuel reduction techniques and a control on breeding birds during 2001‐2005 using 50‐m point counts. Four experimental units, each >14 ha, were contained within each of 3 replicate blocks at the Green River Game Land, Polk County, North Carolina, USA. Treatments were 1) prescribed burn, 2) mechanical understory reduction (chainsaw‐felling of shrubs and small trees), 3) mechanical + burn, and 4) controls. We conducted mechanical treatments in winter 2001‐2002 and prescribed burns in spring 2003. Tall shrub cover was substantially reduced in all treatments compared to controls. Tree mortality and canopy openness was highest in the mechanical + burn treatment after burning, likely due to higher fuel loading and hotter burns; tree mortality increased with time. Many bird species did not detectably decrease or increase in response to treatments. Species richness, total bird density, and some species, including indigo buntings (Passerina cyanea) and eastern bluebirds (Sialia sialis), increased in the mechanical + burn treatment after a 1‐year to 2‐year delay; eastern woodpewees (Contopus virens) increased immediately after treatment. Hooded warblers (Wilsonia citrina), black‐and‐white warblers (Mniotilta varia), and worm‐eating warblers (Helmitheros vermivorus) declined temporarily in some or all treatments, likely in response to understory and (or) leaf litter depth reductions. Densities of most species affected by treatments varied with shrub cover, tree or snag density, or leaf litter depth. High snag availability, open conditions, and a higher density of flying insects in the mechanical + burn treatment likely contributed to increased bird density and species richness. In our study, fuel reduction treatments that left the canopy intact, such as low‐intensity prescribed fire or mechanical understory removal, had few detectable effects on breeding birds compared to the mechanical + burn treatment. High‐intensity burning with heavy tree‐kill, as occurred in our mechanical + burn treatment, can be used as a management tool to increase densities of birds associated with open habitat while retaining many forest and generalist species, but may have short‐term adverse effects on some species that are associated with the ground‐ or shrub‐strata for nesting and foraging.

Biodiversity and Edge Effects: An Activity in Landscape Ecology

Biodiversity and the conservation of biodiversity have received increased attention during the last few decades and these topics have been implemented into many G7-12 science curricula. This work presents an exercise that may be used in middle and high school classrooms to help students better understand spatial aspects of biodiversity. The following activity was successfully implemented into 8th grade science classes to strengthen student understanding of biodiversity. In the activity, students are provided a sample dataset created using point-count surveys of avian species along a transect extending from forest interior to open field locations. Students are asked to calculate and analyze total bird density (n), species composition, species richness (S), and species diversity (H'). By analyzing the data, students observe how these measures change along the vegetation gradient. The activity can easily be adjusted to accommodate a variety of skill levels and class times.