Songbirds incidentally ingest soil contaminated with lead and several species in the Southeast Missouri Lead Mining District have a negative relationship between soil lead concentration and reproduction. We used an individual-based model (IBM) to simulate nesting processes throughout the breeding season to estimate annual productivity for 5 songbirds in relation to soil-lead concentration. We modeled daily nest survival and number fledged in relation to soil lead and incorporated these relationships into the IBM using a Bayesian approach that fully captured parameter uncertainty and process variation. The proportion of the posterior distribution for the effect of soil lead on daily nest survival was mostly negative for Pipilo erythrophthalmus (Eastern Towhee), Passerina cyanea (Indigo Bunting), Cardinalis cardinalis (Northern Cardinal), Sialia sialis (Eastern Bluebird; f = 0.972, 0.990, 0.741, 0.581, respectively), and slightly positive for Spizella pusilla (Field Sparrow; f = 0.680). The proportion of the posterior distribution for the effect of soil lead on the number fledged from successful nests was mostly negative for S. pusilla, P. erythrophthalmus, and C. cardinalis (f = 0.867, 0.585, 0.508, respectively) and positive for P. cyanea and S. sialis (f = 0.773, 0.744). Simulated annual productivity decreased by 0.04-1.47 young/female/year among species across the range of soil lead concentrations, with the greatest declines for P. erythrophthalmus and P. cyanea. The probability of fledging one or more young changed from 51% to 15% for P. erythrophthalmus, 57% to 23% for P. cyanea, 60% to 48% for C. cardinalis, 94% to 84% for S. sialis, and 57% to 64% for S. pusilla as soil-lead concentration around a nest increased from 20 to 4,000 ppm. Most nest failures were the result of predation; therefore, we suggest lead may have affected birds' behavior at the nest, or affected nest site quality, which resulted in higher nest predation. center dot Songbirds incidentally consume soil contaminated with lead while foraging near mining operations. Previous research in the Southeast Missouri Lead Mining District found a negative relationship between soil lead concentration and some songbird reproductive parameters, such as nest survival and number of young fledged.center dot We used data from this earlier study in an individual-based model to predict annual productivity by a female in a breeding season at increasing soil lead levels.center dot Annual productivity decreased by 0.04-1.47 offspring/female/year and the probability of fledging one or more young changed from 51% to 15% for Pipilo erythrophthalmus (Eastern Towhee), 57% to 23% for Passerina cyanea (Indigo Bunting), 60% to 48% for Cardinalis cardinalis (Northern Cardinal), 94% to 84% for Sialia sialis (Eastern Bluebird), and 57% to 64% for Spizella pusilla (Field Sparrow) as soil-lead concentrations increased.center dot Most nest failures were due to predation; therefore, we suggest possible explanations for the reduction in productivity are that lead affected birds' behavior and activity at the nest, or affected nest site quality, and resulted in higher nest predation. Las aves canoras ingieren incidentalmente suelo contaminado con plomo y varias especies en el Distrito Minero de Plomo del sureste de Missouri tienen una relaci & oacute;n negativa entre la concentraci & oacute;n de plomo en el suelo y la reproducci & oacute;n. Utilizamos un modelo basado en individuos (MBI) para simular los procesos de anidaci & oacute;n a lo largo de la temporada reproductiva para estimar la productividad anual de cinco aves canoras en relaci & oacute;n con la concentraci & oacute;n de plomo en el suelo. Modelamos la supervivencia diaria del nido y el n & uacute;mero de volantones en relaci & oacute;n con el plomo en el suelo e incorporamos estas relaciones en el MBI usando un enfoque bayesiano que captur & oacute; completamente la incertidumbre de los par & aacute;metros y la variaci & oacute;n del proceso. La proporci & oacute;n de la distribuci & oacute;n posterior para el efecto del plomo en el suelo sobre la supervivencia diaria del nido fue mayormente negativa para Pipilo erythrophthalmus, Passerina cyanea, Cardinalis cardinalis y Sialia sialis (f = 0.972, 0.990, 0.741, 0.581, respectivamente) y ligeramente positiva para Spizella pusilla (f = 0.680). La proporci & oacute;n de la distribuci & oacute;n posterior para el efecto del plomo en el suelo sobre el n & uacute;mero de volantones de nidos exitosos fue mayormente negativa para S. pusilla, P. erythrophthalmus y C. cardinalis (f = 0.867, 0.585, 0.508, respectivamente) y positiva para P. cyanea y S. sialis (f = 0.773, 0.744). La productividad anual simulada disminuy & oacute; en 0.04-1.47 j & oacute;venes/hembra/a & ntilde;o entre las especies a lo largo del rango de concentraciones de plomo en el suelo, con las mayores disminuciones para P. erythrophthalmus y P. cyanea. La probabilidad de emplumar uno o m & aacute;s j & oacute;venes cambi & oacute; del 51% al 15% para P. erythrophthalmus, del 57% al 23% para P. cyanea, del 60% al 48% para C. cardinalis, del 94% al 84% para S. sialis, y del 57% al 64% para S. pusilla a medida que la concentraci & oacute;n de plomo en el suelo alrededor de un nido aument & oacute; de 20 a 4000 ppm. La mayor & iacute;a de los fracasos de los nidos fueron resultado de la depredaci & oacute;n; por lo tanto, sugerimos que el plomo puede haber afectado el comportamiento de las aves en el nido, o afectado la calidad del sitio del nido, lo que result & oacute; en una mayor depredaci & oacute;n de los nidos.

First posted August 11, 2023 For additional information, contact: Director, Columbia Environmental Research CenterU.S. Geological Survey4200 New Haven RoadColumbia, MO 65201Contact Pubs Warehouse Lead mining in the Southeast Missouri Lead Mining District began in the 1700s and continued for nearly 300 years; the waste piles associated with smelting, mining, and milling of lead ores have released metal residues that have contaminated soil and water in the region. Previous studies in the district have indicated potential harm to wildlife, including birds, because of elevated lead concentrations associated with mining. Exposure to soil-borne lead was correlated with elevated lead concentrations in tissues, inhibition of δ-aminolevulinic acid dehydratase (δALAD), and renal lesions in birds foraging on ground-dwelling invertebrates at contaminated sites (compared to reference sites) in the Southeast Missouri Lead Mining District.This study assessed reproductive outcomes for songbirds exposed to soil-borne lead in the district, examined the relation between lead concentrations in soils and in tissues of ground-feeding birds and prey species, and compared the results to literature-based toxicity thresholds for lead that are associated with negative effects in birds. Three lead-contaminated sites and three reference sites (with background concentrations of lead and no known mining inputs) were compared in two ways: individually to all other sites or by site type. Additional effects of lead exposure were evaluated by examining concentrations of biomarkers (oxidative stress, lipid peroxidation, and deoxyribonucleic acid damage) in liver tissues, δALAD inhibition, and renal and hepatic microscopic lesions in birds from lead-contaminated and reference sites.Lead concentrations in soil were site-dependent and were also generally heterogeneous within the lead-contaminated sites. Between 17 and 74 percent of all soil samples at contaminated sites had lead concentrations that exceeded a threshold (1,000 milligrams per kilogram [mg/kg] lead in soil) previously associated with adverse physiological effects in birds in the Southeast Missouri Lead Mining District. Lead concentrations in mixed invertebrates from lead-contaminated sites (282 to 2,230 mg/kg dry weight [dw]) indicated that consuming soil-dwelling prey species is a potential exposure pathway for adult birds and their broods. At lead-contaminated sites, lead concentrations in 40.5 percent of blood samples (adults and their broods) were within a subclinical effects range (0.9 to 2.3 mg/kg dw), and 18.7 percent of samples had lead concentrations that exceeded clinical effects criteria (greater than 2.3 mg/kg dw). In contrast, only 2.6 percent of blood samples from reference sites were within the subclinical effects range for lead; all other blood samples from the reference sites had lead concentrations representative of background concentrations (less than 0.9 mg/kg dw). Subclinical and clinical threshold exceedances for lead concentrations in livers and kidneys were similarly more prevalent at the contaminated sites compared to the reference sites.Lead concentrations in blood were positively correlated with lead concentrations in soil, livers, and kidneys. Lead concentrations in blood were negatively correlated with δALAD activity; greater than 50 percent of the birds collected at lead-contaminated sites exhibited injury via greater than 50 percent inhibition of δALAD in blood compared to birds at reference sites. Birds with elevated lead concentrations in tissues also exhibited enhanced oxidative stress. Microscopic lesions in the livers and kidneys of birds had similar rates of occurrence at the contaminated and reference sites, and lesion prevalence could not be directly linked to lead exposure. Reproductive success was monitored at 585 nests, and 3 out of 5 species had reduced nest success associated with elevated lead concentrations in soil; habitat measures did not help explain nest success. Reduced nest success may have resulted from greater nest predation resulting from neurological and behavioral effects of lead exposure. Ultimately, these lines of evidence indicate that bird health and reproduction have been negatively affected by exposure to lead-contaminated soils in the Southeast Missouri Lead Mining District.

Chuck-will's-widow (Antrostomus carolinensis) and eastern whip-poor-will (Antrostomus vociferus) are nightjars in eastern North America that have declined 69% and 67%, respectively, in abundance since 1966, resulting in conservation concerns for these species. We investigated relationships between nightjar abundance and landscape composition, forest structure, and application of tree thinning and prescribed fire because of regional interest in woodland restoration and nightjar conservation. We conducted nocturnal nightjar surveys at 385 points in southern Missouri, USA, in 2014 and 2015 and related counts to pine (Pinus spp.) and hardwood basal area, canopy closure, percent forest cover, and percent of area thinned or burned within 500 m of survey points. We modeled abundance of chuck-will's-widow and eastern whip-poor-will using time-removal models that included a detection process and an abundance process within a hierarchical Bayesian framework. We detected 534 eastern whip-poor-will and 186 chuck-will's-widow during surveys. Our data supported global models that included all 6 vegetation and management variables for both species. Chuck-will's-widow abundance was negatively related to hardwood basal area and peaked at intermediate values of percent area burned and percent forest cover. Eastern whip-poor-will abundance was negatively related to hardwood basal area and canopy cover, positively related to percent forest cover and percent of area burned, and peaked at low to moderate levels of percent of area thinned. Relationships to forest structure and management activities generally supported the conclusion that woodland restoration benefits nightjars and that chuck-will's-widow select landscapes with less forest cover than eastern whip-poor-will.

Restoration is underway to restore lost or degraded remnants of savanna and woodland in the Midwestern United States in the hopes of restoring floristic and wildlife diversity. Information is needed on the effects of pine savanna-woodland restoration on bird abundance to inform management decisions. We conducted point-count surveys for 19 bird species across the gradient of savanna, woodland, and forest in restored and non-restored areas throughout the Ozark-Ouachita Highlands in parts of Missouri, Arkansas, and Oklahoma during the 2013-2015 breeding seasons. We estimated densities of 16 species using distance sampling to account for detection probability, and we determined relationships of bird abundance with management and vegetation variables by evaluating support for a priori models. Densities of early-successional and generalist species were positively related, and interior-forest species negatively related, to restoration. Densities of Brown-headed Nuthatch (Sitta pusilla), Eastern Towhee (Pipilo erythrophthalmus), Eastern Wood-Pewee (Contopus virens), Pine Warbler (Setophaga pinus), Prairie Warbler (Setophaga discolor), Red-headed Woodpecker (Melanerpes erythrocephalus), White-eyed Vireo (Vireo griseus), and Yellow-breasted Chat (Icteria virens) were positively related to prescribed fire activity. Blue-winged Warbler (Vermivora cyanoptera), Kentucky Warbler (Geothlypis formosa), and Yellow-breasted Chat densities were positively related to tree thinning. Many species had higher densities in areas with less canopy cover, tree density, and forest cover. Acadian Flycatcher (Empidonax virescens), Black-and white Warbler (Mniotilta varia), Ovenbird (Seiurus aurocapilla), Wood Thrush (Hylocichla mustelina), and Worm eating Warbler (Helmitheros vermivorum) were negatively related to one or more aspects of restoration treatment and generally preferred areas with greater tree density and canopy cover. Summer Tanagers (Piranga rubra) were abundant but density was not strongly related to management or vegetation variables. Restoration provided breeding habitat for disturbance-dependent species and woodland generalists, many of which are species of conservation concern, but canopy cover generally remained too great for species that require more open savanna.

Savanna and woodland are transitional vegetation communities that have largely disappeared while many early-successional bird species have simultaneously declined in abundance. Pine savanna and woodland are being restored in the Midwest through prescribed fire and tree thinning to create their characteristic open canopy, dense ground layer, and variable shrub cover. Ideally, these restoration strategies for vegetation should also facilitate bird conservation objectives. We determined daily nest survival (DSR) for 6 songbird species, representing both shrub-nesting and canopy-nesting species, in southern Missouri, USA, in 2014 and 2015. We evaluated support for hypotheses relating temporal, vegetation, and management factors to DSR. We predicted that nest survival of the 3 shrub-nesting species (Eastern Towhee [Pipilo erythrophthalmus], Yellow-breasted Chat [lcteria virens], and Prairie Warbler [Setophaga discolor]) would show positive relationships with thinning and fire, but only Yellow-breasted Chat DSR was positively related to tree thinning. However, pooling species into a shrub-nesting guild resulted in a positive relationship of nest survival with tree thinning and a weak relationship with fire. For canopy-nesters, Eastern Wood-Pewee (Contopus virens) and Summer Tanager (Piranga rubra) DSR was negatively related to mean canopy cover, and Pine Warbler (Setophaga pinus) DSR was weakly related to tree density by size class. The canopy-nesting guild had higher DSR in thinned areas with lower basal area and less canopy cover. Our results demonstrate that pine savanna-woodland restoration in Missouri is providing high-quality breeding habitat for both shrub-nesting and canopy-nesting species, some of which are species of conservation concern.