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At least 109 records · Page 6Linked to original sources

USGS2014

Influences of the Tamarisk Leaf Beetle ( Diorhabda carinulata ) on the diet of insectivorous birds along the Dolores River in Southwestern Colorado

We examined the effects of a biologic control agent, the tamarisk leaf beetle (Diorhabda carinulata), on native avifauna in southwestern Colorado, specifically, addressing whether and to what degree birds eat tamarisk leaf beetles. In 2010, we documented avian foraging behavior, characterized the arthropod community, sampled bird diets, and undertook an experiment to determine whether tamarisk leaf beetles are palatable to birds. We observed that tamarisk leaf beetles compose 24.0 percent (95-percent-confidence interval, 19.9-27.4 percent) and 35.4 percent (95-percent-confidence interval, 32.4-45.1 percent) of arthropod abundance and biomass in the study area, respectively. Birds ate few tamarisk leaf beetles, despite a superabundance of D. carinulata in the environment. The frequency of occurrence of tamarisk leaf beetles in bird diets was 2.1 percent (95-percent-confidence interval, 1.3- 2.9 percent) by abundance and 3.4 percent (95-percent-confidence interval, 2.6-4.2 percent) by biomass. Thus, tamarisk leaf beetles probably do not contribute significantly to the diets of birds in areas where biologic control of tamarisk is being applied.

Colorado;Utah↗

USGS2024

Nutrient chemistry in the Elizabeth Lake subwatershed—Effects of onsite wastewater treatment systems on groundwater and lake water quality, Los Angeles County, California

Nutrient (nitrogen [N] and phosphorus [P] chemistry) downgradient from onsite wastewater treatment system (OWTS) was evaluated with a groundwater study in the area surrounding Elizabeth Lake, the largest of three sag lakes within the Santa Clara River watershed of Los Angeles County, California. Elizabeth Lake is listed on the “303 (d) Impaired Waters List” for excess nutrients and is downgradient from more than 600 OWTS. The primary objective of this study was to develop a conceptual hydrogeological model to determine if discharge from OWTS is transported into shallow groundwater within the Elizabeth Lake subwatershed and contributes nutrients to Elizabeth Lake in excess of the total maximum daily load limit. An analysis of historical data and data collected for this study provided estimates of aquifer properties, such as hydraulic gradients and other parameters necessary to estimate boundary conditions. Electrical resistivity tomography (ERT) surveys were done to determine the best monitoring well locations and to estimate depth to groundwater. During 4 separate sampling events, 11 wells, 2 imported water tanks, 1 spring (sampled on March 17, 2019), and Elizabeth Lake were sampled, which occurred during February–September 2020. ERT transects and borehole geophysical measurements indicated that there were low to high resistivity materials in the subsurface and potential perched fresh water. Most of the aquifer material was characterized as sandy silt, occasionally with mixed clays and medium gravels, and was estimated to have a hydraulic conductivity from 3.28x10 −3 to 16.4 feet per day, a porosity from 0.34 to 0.42, and a hydraulic gradient from 0.01 to 0.03. Although bedrock was not obvious in ERT transects, all well depths were terminated at depths of an impassible confining layer observed to be a highly consolidated blue-gray clay. Depths to granitic bedrock, based on road outcrops and lithologic driller logs, varied throughout the study area. Depth to the bedrock was estimated to be shallow on the north side of Elizabeth Lake at approximately 30 feet below land surface (ft bls). Depth to bedrock is at 50 ft bls toward the east of the Elizabeth Lake subwatershed, which is at topographic ground surface to the north and south of the residential development. Groundwater levels ranged from approximately 0 to 12 ft bls during this study. Historical water levels ranged from 8 to 16 ft bls in the lower elevation of the study area and increased to depths of as much as 80 ft bls at higher elevations on the north and south boundaries of the Elizabeth Lake subwatershed. Water-quality samples were analyzed for major ions, nutrients, dissolved organic carbon, stable isotopes, and age-dating tracers. A principal component analysis was completed to determine organic matter sources. The proportion of recharge from imported waters, used for domestic consumption, was calculated using stable water isotopes, deuterium (δD) and oxygen (δ 18 O). Recharge from imported waters accounted for approximately 15–71 percent of the total recharge to groundwater within the study area. Total nitrogen concentrations ranged from 0.17 to 30.9 milligrams per liter (mg/L) as N, and phosphorus, measured in the soluble form as orthophosphate, ranged from 0.03 to 0.35 mg/L as P. Nitrate concentrations in groundwater samples ranged from less than the detection limit (0.01 mg/L as N) to approximately 24 mg/L as N. Nitrate was not detected in 3 of the 12 sites sampled during the study (2 wells and Elizabeth Lake). Dissolved organic carbon concentrations ranged from 0.4 to 27 mg/L in groundwater and from 9.9 to 100 mg/L in Elizabeth Lake. Ammonium and orthophosphate concentrations generally were low in groundwater. However, elevated concentrations of ammonium in Elizabeth Lake were assumed to be due to avian waste products or biological nitrogen fixation. Groundwater ages were mostly modern (recharged since 1952), with a median recharge temperature of 13 degrees Celsius. Redox conditions in groundwater indicated the likely occurrence of nitrate attenuation by denitrification downgradient from the wells to the south of Elizabeth Lake before groundwater discharges to the lake. Undetectable nitrate in Elizabeth Lake at the time of sampling was likely due to algal uptake. Most wells contained stable isotopes of nitrogen and oxygen in nitrate (δ 15 N-NO 3 and δ 18 O-NO 3 ) molecules with values consistent with denitrification. However, one monitoring well on the north of Elizabeth Lake (ELLA-8) had no evidence of denitrification, based on elevated concentrations of nitrate and a sufficient amount of dissolved oxygen such that the water was oxic and not favorable for the denitrification reaction. Consequently, this nitrate could be delivered to Elizabeth Lake through groundwater discharge if nitrate is not removed from the system by denitrifying bacteria downgradient from the well before the groundwater discharges into Elizabeth Lake. The principal component analysis demonstrated that dissolved organic matter optical properties track different sources of dissolved organic matter from decayed plants, animals, and animal-derived wastes. Two wells contained strong indicators of OWTS water presence, although geochemical evidence indicated other wells may also be affected by OWTS discharge.

California↗

USGS2026

Cost of migration increased during an outbreak of highly pathogenic avian influenza virus

Migration is thought to be costly such that challenges faced during migration likely affect how birds migrate through direct selection on migratory behavior. Survival throughout the annual cycle and conditions that affect the survival costs of migration are therefore critical to our understanding of the causes and consequences of migration. Estimating daily survival throughout the annual cycle of migratory birds has only recently become possible. We used over a decade of GPS tracking data from 186 migratory Buteo lagopus to quantify causes of mortality as well as demographic, seasonal, and spatial variation in daily survival and how survival consequences of migration changed during an outbreak of highly pathogenic avian influenza virus. The cost of migration via direct mortality varied between avian influenza and baseline study periods. Surprisingly, mortality risk during typical spring migrations was lower than in all other seasons, but mortality risk during the avian influenza outbreak was higher during both spring and fall migrations. Additionally, we found increased mortality risk in females during the avian influenza outbreak but no sex differences during baseline periods. Hence, the relative cost of migration was altered by the virus. During baseline periods, mortality risk was highest during late fall migration and winter, coinciding with increased anthropogenic-related mortalities at lower latitudes. However, the number of deaths caused by avian influenza (n = 11) in a single year equaled the total number of deaths caused by anthropogenic-related factors (n = 11; primarily collision trauma and persecution) across all 12 study years. Overall, our study highlights how added stressors such as disease outbreaks and anthropogenic factors may exacerbate existing seasonal constraints by directly increasing mortality risk.

Journal of Avian Biology↗

USGS2017

Multidirectional abundance shifts among North American birds and the relative influence of multifaceted climate factors

Shifts in species distributions are major fingerprint of climate change. Examining changes in species abundance structures at a continental scale enables robust evaluation of climate change influences, but few studies have conducted these evaluations due to limited data and methodological constraints. In this study, we estimate temporal changes in abundance from North American Breeding Bird Survey data at the scale of physiographic strata to examine the relative influence of different components of climatic factors and evaluate the hypothesis that shifting species distributions are multidirectional in resident bird species in North America. We quantify the direction and velocity of the abundance shifts of 57 permanent resident birds over 44 years using a centroid analysis. For species with significant abundance shifts in the centroid analysis, we conduct a more intensive correlative analysis to identify climate components most strongly associated with composite change of abundance within strata. Our analysis focus on two contrasts: the relative importance of climate extremes vs. averages, and of temperature vs. precipitation in strength of association with abundance change. Our study shows that 36 species had significant abundance shifts over the study period. The average velocity of the centroid is 5.89 km·yr −1 . The shifted distance on average covers 259 km, 9% of range extent. Our results strongly suggest that the climate change fingerprint in studied avian distributions is multidirectional. Among 6 directions with significant abundance shifts, the northwestward shift was observed in the largest number of species ( n = 13). The temperature/average climate model consistently has greater predictive ability than the precipitation/extreme climate model in explaining strata‐level abundance change. Our study shows heterogeneous avian responses to recent environmental changes. It highlights needs for more species‐specific approaches to examine contributing factors to recent distributional changes and for comprehensive conservation planning for climate change adaptation.

Global Change Biology↗

USGS2015

Avian malaria in Hawaiian forest birds: Infection and population impacts across species and elevations

Wildlife diseases can present significant threats to ecological systems and biological diversity, as well as domestic animal and human health. However, determining the dynamics of wildlife diseases and understanding the impact on host populations is a significant challenge. In Hawai‘i, there is ample circumstantial evidence that introduced avian malaria ( Plasmodium relictum ) has played an important role in the decline and extinction of many native forest birds. However, few studies have attempted to estimate disease transmission and mortality, survival, and individual species impacts in this distinctive ecosystem. We combined multi-state capture-recapture (longitudinal) models with cumulative age-prevalence (cross-sectional) models to evaluate these patterns in Apapane, Hawai‘i Amakihi, and Iiwi in low-, mid-, and high-elevation forests on the island of Hawai‘i based on four longitudinal studies of 3–7 years in length. We found species-specific patterns of malaria prevalence, transmission, and mortality rates that varied among elevations, likely in response to ecological factors that drive mosquito abundance. Malaria infection was highest at low elevations, moderate at mid elevations, and limited in high-elevation forests. Infection rates were highest for Iiwi and Apapane, likely contributing to the absence of these species in low-elevation forests. Adult malaria fatality rates were highest for Iiwi, intermediate for Amakihi at mid and high elevations, and lower for Apapane; low-elevation Amakihi had the lowest malaria fatality, providing strong evidence of malaria tolerance in this low-elevation population. Our study indicates that hatch-year birds may have greater malaria infection and/or fatality rates than adults. Our study also found that mosquitoes prefer feeding on Amakihi rather than Apapane, but Apapane are likely a more important reservoir for malaria transmission to mosquitoes. Our approach, based on host abundance and infection rates, may be an effective alternative to mosquito blood meal analysis for determining vector-host contacts when mosquito densities are low and collection of blood-fed mosquitoes is impractical. Our study supports the hypothesis that avian malaria has been a primary factor influencing the elevational distribution and abundance of these three species, and likely limits other native Hawaiian species that are susceptible to malaria.

Hawai'i↗

USGS2016

Habitat selection by postbreeding female diving ducks: Influence of habitat attributes and conspecifics

Habitat selection studies of postbreeding waterfowl have rarely focused on within-wetland attributes such as water depth, escape cover, and food availability. Flightless waterfowl must balance habitat selection between avoiding predation risks and feeding. Reproductively successful female ducks face the greatest challenges because they begin the definitive prebasic molt at or near the end of brood rearing, when their body condition is at a low point. We assessed the relative importance of habitat attributes and group effects in habitat selection by postbreeding female lesser scaup Aythya affinis on a 2332-ha montane wetland complex during the peak flightless period (August) over seven years. Hypothesis-based habitat attributes included percent open water, open water:emergent edge density, water depth, percent flooded bare substrate, fetch (distance wind can travel unobstructed), group size, and several interactions representing functional responses to interannual variation in water levels. Surveys of uniquely marked females were conducted within randomly ordered survey blocks. We fitted two-part generalized linear mixed-effects models to counts of marked females within survey blocks, which allowed us to relate habitat attributes to relative probability of occurrence and, given the presence of a marked female, abundance of marked individuals. Postbreeding female scaup selected areas with water depths > 40 cm, large open areas, and intermediate edge densities but showed no relation to flooded bare substrate, suggesting their habitat preferences were more influenced by avoiding predation risks and disturbances than in meeting foraging needs. Grouping behavior by postbreeding scaup suggests habitat selection is influenced in part by behavioral components and/or social information, conferring energetic and survival benefits (predation and disturbance risks) but potentially also contributing to competition for food resources. This study demonstrates the importance of incorporating group effects and interannual variability in habitat conditions when investigating habitat selection, particularly for seasons when waterfowl are aggregated.

Journal of Avian Biology↗

USGS2010

Victims and vectors: highly pathogenic avian influenza H5N1 and the ecology of wild birds

The emergence of highly pathogenic avian influenza (HPAI) viruses has raised concerns about the role of wild birds in the spread and persistence of the disease. In 2005, an outbreak of the highly pathogenic subtype H5N1 killed more than 6,000 wild waterbirds at Qinghai Lake, China. Outbreaks have continued to periodically occur in wild birds at Qinghai Lake and elsewhere in Central China and Mongolia. This region has few poultry but is a major migration and breeding area for waterbirds in the Central Asian Flyway, although relatively little is known about migratory movements of different species and connectivity of their wetland habitats. The scientific debate has focused on the role of waterbirds in the epidemiology, maintenance and spread of HPAI H5N1: to what extent are they victims affected by the disease, or vectors that have a role in disease transmission? In this review, we summarise the current knowledge of wild bird involvement in the ecology of HPAI H5N1. Specifically, we present details on: (1) origin of HPAI H5N1; (2) waterbirds as LPAI reservoirs and evolution into HPAI; (3) the role of waterbirds in virus spread and persistence; (4) key biogeographic regions of outbreak; and (5) applying an ecological research perspective to studying AIVs in wild waterbirds and their ecosystems.

Avian Biology Research↗

USGS2006

Predictors of introduction success in the South Florida avifauna

Biological invasions are an increasing global challenge, for which single-species studies and analyses focused on testing single hypotheses of causation in isolation are unlikely to provide much additional insight. Species interact with other species to create communities, which derive from species interactions and from the interactions of species with the scale specific elements of the landscape that provide suitable habitat and exploitable resources. I used logistic regression analysis to sort among potential intrinsic, community and landscape variables that theoretically influence introduction success. I utilized the avian fauna of the Everglades of South Florida, and the variables body mass, distance to nearest neighbor (in terms of body mass), year of introduction, presence of congeners, guild membership, continent of origin, distribution in a body mass aggregation or gap, and distance to body-mass aggregation edge (in terms of body mass). Two variables were significant predictors of introduction success. Introduced avian species whose body mass placed them nearer to a body-mass aggregation edge and further from their neighbor were more likely to become successfully established. This suggests that community interactions, and community level phenomena, may be better understood by explicitly incorporating scale. ?? Springer 2006.

Biological Invasions↗

USGS2009

A tangled tale of two teal: Population history of the grey Anas gracilis and chestnut teal a. castanea of Australia

Two Australian species of teal (Anseriformes: Anatidae: Anas), the grey teal Anas gracilis and the chestnut teal A. castanea, are remarkable for the zero or near-zero divergence recorded between them in earlier surveys of mitochondrial DNA (mtDNA) diversity. We confirmed this result through wider geographical and population sampling as well as nucleotide sampling in the more rapidly evolving mtDNA control region. Any data set where two species share polymorphism as is the case here can be explained by a model of gene flow through hybridization on one hand or by incomplete lineage sorting on the other hand. Ideally, analysis of such shared polymorphism would simultaneously estimate the likelihood of both phenomena. To do this, we used the underlying principle of the IMa package to explore ramifications to understanding population histories of A. gracilis and A. castanea. We cannot reject that hybridization occurs between the two species but an equally or more plausible finding for their nearly zero divergence is incomplete sorting following very recent divergence between the two, probably in the mid-late Pleistocene. Our data add to studies that explore intermediate stages in the evolution of reciprocal monophyly and paraphyletic or polyphyletic relationships in mtDNA diversity among widespread Australian birds. ?? 2009 J. Avian Biol.

Journal of Avian Biology↗

USGS2000

Species variation in osmotic, cryoprotectant, and cooling rate tolerance in poultry, eagle, and Peregrine Falcon spermatozoa

Potential factors influencing spermatozoa survival to cryopreservation and thawing were analyzed across a range of the following avian species: domestic chicken ( Gallus domesticus ), domestic turkey ( Meleagris gallopavo ), golden eagle ( Aquila chrysaetos ), Bonelli’s eagle ( Hieraaetus fasciatus ), imperial eagle ( Aquila adalberti ), and peregrine falcon ( Falco peregrinus ). Studies focused on spermatozoa tolerance to the following: 1) osmotic stress, 2) different extracellular concentrations of the cryoprotectant dimethylacetamide (DMA), 3) equilibration times of 1 versus 4 h, 4) equilibration temperature of 4 versus 21°C, and 5) rapid versus slow cooling before cryopreservation and standard thawing. Sperm viability was assessed with the live/dead stain (SYBR-14/propidium iodine). Sperm viability at osmolalities ≥800 mOsm was higher ( P < 0.05) in raptor than poultry semen. Return to isotonicity after exposure to hypertonicity (3000 mOsm) decreased ( P < 0.05) number of viable spermatozoa in chicken, turkey, and golden and Bonelli’s eagle spermatozoa but not in imperial eagle or peregrine falcon spermatozoa. Differences were found in spermatozoa resistance to hypotonic conditions, with eagle species demonstrating the most tolerance. Semen, equilibrated for 1 h (4°C) in diluent containing DMA (≥2.06 M), experienced decreased ( P < 0.05) spermatozoa survival in all species, except the golden eagle and peregrine falcon. Number of surviving spermatozoa diminished progressively with increasing DMA concentrations in all species. Increased equilibration temperature (from 4 to 21°C) markedly reduced ( P < 0.05) spermatozoa survival in all species except the Bonelli’s eagle and turkey. Rapid cooling was detrimental ( P < 0.05) to spermatozoa from all species except the imperial eagle and the chicken. These results demonstrate that avian spermatozoa differ remarkably in response to osmotic changes, DMA concentrations, equilibration time, temperature, and survival after fast or slow freezing. These differences emphasize the need for species-specific studies in the development and enhancement of assisted breeding for poultry and endangered species.

Biology of Reproduction↗

USGS1996

The relevance of the Mediterranean Region to colonial waterbird conservation

The Mediterranean Sea is the largest partially enclosed sea in the world and provides habitat to more than 100 species of waterbirds from the Palearctic-North African-Middle Eastern regions. Even though the Mediterranean suffers from pollution, has little tidal influence, and is oligotrophic, more than half of the western Palearctic populations of numerous waterfowl species winter in the region. Thirty-three species of colonial waterbirds breed along the 46,000 km Mediterranean coastline with nine species considered threatened or endangered, mostly because of wetland loss and degradation. The long history of human activity and scientific investigations in the region has taught some valuable lessons. In the area of colonial waterbird biology and conservation, we have learned important lessons about the value of long-term monitoring and research on selected populations. From marking studies of Greater Flamingos (Phoenicopterus ruber roseus) and Little Egrets (Egretta garzetta) results have been used to derive useful information about metapopulation dynamics. Involvement of both African and European biologists allowed year-round Studies of these species that yielded valuable spin-offs for training in avian and wetland conservation. We have also learned the value of man-made wetlands as feeding and nesting sites for some colonial waterbirds. Careful evaluations of the habitat quality of different types of wetlands are required, as in contaminant levels such as lead shot and pesticides. Wetland conservationists have also learned from some instructive mistakes. Dam construction and agricultural incentive programs sponsored by the European Community, the World Bank, and others from the past have largely ignored impacts on wetlands and wildlife. In some areas, economic ventures such as aquaculture operations and salt mining have not involved waterbird habitat needs in their planning. Research and conservation needs include: (1) establishing regional monitoring programs and data banks for seabirds, wading birds, ducks, and geese; (2) implementing a wetland inventory for many Countries with little quantitative data on wetlands; (3) improving habitat quality assessments; (4) improving relationships with industry, the private citizenry, and government officials to further an appreciation for the value of wetlands and waterbirds; (5) enhancing training efforts, especially in underdeveloped Countries; (6) evaluating the effects of hunting and other disturbances to nesting and feeding waterbirds in different regions; (7) setting up 'sister-reserve' (twinned) sites in Europe and Africa to foster international linkages and training; and (8) fostering local-regional conservation programs to preserve reed beds, wet woodlots, and other key habitats.

Book chapter↗

USGS2022

Hawaiian forest bird conservation strategies for minimizing the risk of extinction: biological and biocultural considerations

The iconic forest birds of Hawai‘i are facing a conservation crisis. Across the Hawaiian Islands, native forest birds have been experiencing population declines that have accelerated in the last one to two decades. While habitat loss, invasive species, and non-native predators have negatively affected forest bird species for hundreds of years, and continue to do so, introduced diseases, particularly avian malaria, are the greatest threat to forest birds today. Further, climate change has increased temperatures in the high-elevation forests, facilitating the spread of disease into areas that were once largely disease-free. Rapid population declines have now (2022) pushed four Hawaiian honeycreeper species to the brink of extinction: the endangered ‘akikiki ( Oreomystis bairdi ) and ‘akeke‘e ( Loxops caeruleirostris ) on Kaua‘i Island, and kiwikiu ( Pseudonestor xanthophrys ) and ‘ākohekohe ( Palmeria dolei ) on Maui Island. The biologists that study these birds strongly agree that without a rapid conservation response to the threat of increasing disease mortality there is a high probability these species will go extinct in the coming decade. To help evaluate alternative conservation strategies for minimizing the risk of extinction, we convened diverse groups of experts with broad experience in Hawai‘i forest birds and ecosystems, as well as the management approaches being considered, to assess the probability of success of alternative management actions. In addition to assessing this crisis from a biological perspective, we convened a group of Native Hawaiian participants that have a strong connection to the forest birds, forests, and the integration of their culture in natural and biocultural resource management. They give voice to the significance of forest birds to Native Hawaiians and provide their perspectives on alternative management actions. Broadly, the three alternative management actions being considered to prevent the extinction of forest birds from the increasing threat of disease are (1) landscape-level mosquito control through the Wolbachia incompatible insect technique, (2) captive care, and (3) conservation translocations. The two key components of the problem of preventing extinction in these four bird species is time and risk. For each species, very few individuals remain, and they are all in danger of imminent extinction. Each management action takes time to implement, which might exceed the actual time to extinction. Additionally, each of these conservation actions has potential benefits and inherent risks, as well as substantial uncertainty in terms of being successful. Native Hawaiian perspectives and considerations also vary across the conservation actions. The expert evaluations summarized in this report provide a broad assessment of conservation strategies that could be undertaken to prevent the extinction of ‘akikiki, ‘akeke‘e, kiwikiu, and ‘ākohekohe. While this report does not recommend specific actions, the information is intended to support decision-makers as they assess which, if any, conservation strategies to pursue.

Hawaii↗

USGS2023

Local weather and endogenous factors affect the initiation of migration in short- and medium-distance songbird migrants

Migratory birds employ a variety of mechanisms to ensure appropriate timing of migration based on integration of endogenous and exogenous information. The cues to fatten and depart from the non-breeding area are often linked to exogenous cues such as temperature or precipitation and the endogenous program. Shorter distance migrants should rely heavily on environmental information when initiating migration given relatively close proximity to the breeding area. However, the ability to fatten and subsequently depart may be linked to individual circumstances, including current fuel load and body size. For early and late departing migrants, we investigate effects of temperature, precipitation, lean body mass, fuel load and day of year on the initiation of migration (i.e. fuel load and departure timing) from the non-breeding region by analyzing 21 years of banding data for four species of short- and medium-distance migrants. Temperatures at the non-breeding area were related to temperatures at potential stopover areas. Despite local cues being predictive of conditions further north, the amount variation explained by local weather conditions in our models differed by species and temporal period but was low overall (< 33% variation explained). For each species, we also compared lean body mass and fuel load between early and late departing migrants, which showed mixed results. Our combined results suggest that most individuals migrating short or medium distances in our study did not time the initiation of migration with local predictive cues alone, but rather other factors such as lean body mass, fuel load, day of year, which may be a proxy for the endogenous program, and those beyond the scope of our study also influenced the initiation of migration. Our study contributes to understanding which factors influence departure decisions of short- and medium-distance migrants as they transition from the non-breeding to the migratory phase of the annual cycle.

Louisiana↗

USGS2007

Potential environmental contaminant risks to avian species at important bird areas in the northeastern United States

Environmental contaminants, acting at molecular through population levels of biological organization, can have profound effects upon birds. A screening level risk assessment was conducted that examined potential contaminant threats at 52 Important Bird Areas (IBAs) in the northeastern Atlantic coast drainage. Using geographic information system methodology, data layers describing or integrating pollutant hazards (impaired waters, fish or wildlife consumption advisories, toxic release inventory data, estimated pesticide use and hazard) were overlaid on buffered IBA boundaries, and the relative contaminant threat for each site was ranked. The 10 sites identified as having the greatest contaminant threats included Jefferson National Forest, Stewart B. McKinney National Wildlife Refuge, Great Dismal Swamp National Wildlife Refuge, Blue Ridge Parkway, Shenandoah National Park, Adirondack Park, Edwin B. Forsythe National Wildlife Refuge, George Washington National Forest, Green Mountain National Forest, and Long Island Piping Plover Beaches. These sites accounted for over 50% of the entire study area, and in general had moderate to high percentages of impaired waters, fish consumption advisories related to mercury and PCBs, and were located in counties with substantial application rates of pesticides known to be toxic to birds. Avian species at these IBAs include Federally endangered Roseate terns (Sterna dougallii), threatened piping plovers (Charadrius melodus), neotropical migrants, Bicknell?s thrush (Catharus bicknelli), Swainson?s warbler (Limnothlypis swainsonii) and wintering brant geese (Branta bernicla). Extant data for free-ranging birds from the Contaminant Exposure and Effects--Terrestrial Vertebrates database were examined within the buffered boundaries of each IBA, and for a moderate number of sites there was qualitative concordance between the perceived risk and actual contaminant exposure data. However, several of the IBAs with substantial contaminant hazards (e.g., Blue Ridge Parkway, George Washington National Forest, Shenandoah National Park) had no recent avian ecotoxicological data. Contaminant biomonitoring is warranted at such sites, and data generated from such efforts should foster natural resource management activities.

Book chapter↗

USGS2016

Blood serum chemistry of wild Alaskan Black-capped Chickadees ( Poecile atricapillus ) with avian keratin disorder

We measured serum chemistries in wild Black-capped Chickadees ( Poecile atricapillus ) from Alaska to test for potential differences associated with beak deformities characteristic of avian keratin disorder. Lower uric acid in affected birds was the only difference detected between groups, although sample sizes were small. This difference could be associated with fasting or malnutrition in birds with beak deformities, but it is challenging to interpret its biologic significance without reference values. Black-capped Chickadees had high levels of aspartate aminotransferase, lactate dehydrogenase, and creatine kinase relative to reference values for companion birds. However, all serum chemistry parameters from our study were within the range of values reported from other apparently healthy wild-caught birds.

Journal of Wildlife Diseases↗

USGS2007

Biparental incubation in the chestnut-vented tit-babbler Parisoma subcaeruleum: Mates devote equal time, but males keep eggs warmer

Biparental care in birds is less common during incubation than in other nesting stages. Males share in incubating eggs in a minority of bird species, and male effort is generally thought to be lower than females when sharing does occur. However, male assistance and incubation efficacy is poorly studied in such species. We examined sex differences in incubation effort in 12 pairs of a species with biparental incubation, the chestnut-vented tit-babbler Parisoma subcaeruleum. Males and females did not differ in the amount of time spent incubating during the day, time of day spent incubating, nor in their ability to rewarm eggs. Yet, males consistently maintained eggs at higher temperatures than their female partners, despite the absence of a brood patch. ?? Journal of Avian Biology.

Journal of Avian Biology↗

USGS2019

Temporal changes in avian community composition in lowland conifer habitats at the southern edge of the boreal zone in the Adirondack Park, NY

Climate change represents one of the most significant threats to human and wildlife communities on the planet. Populations at range margins or transitions between biomes can be particularly instructive for observing changes in biological communities that may be driven by climate change. Avian communities in lowland boreal habitats in the Adirondack Park, located at the North American boreal-temperate ecotone, have been the focus of long-term monitoring efforts since 2007. By documenting long-term changes in community structure and composition, such datasets provide an opportunity to understand how boreal species are responding differently to climate change, and which habitat characteristics may be best able to retain boreal avian communities. We examined three specific questions in order to address how well current biological communities in Adirondack boreal wetland habitats are being maintained in a changing climate: (1) how do trends in occupancy vary across species, and what guilds or characteristics are associated with increasing or decreasing occupancy? (2) how is avian community composition changing differently across sites, and (3) what distinguishes sites which are retaining boreal birds to a higher degree than other sites? Our analysis revealed that (1) boreal species appear to exhibit the largest changes in occupancy among our study locations as compared to the larger avian community, (2) dynamics of community change are not uniform across sites and habitat structure may play an important role in driving observed changes, and (3) the particular characteristics of large open peatlands may allow them to serve as refugia for boreal species in the context of climate change.

New York↗

USGS2014

Global phylogeography of the avian malaria pathogen Plasmodium relictum based on MSP1 allelic diversity

Knowing the genetic variation that occurs in pathogen populations and how it is distributed across geographical areas is essential to understand parasite epidemiology, local patterns of virulence, and evolution of host-resistance. In addition, it is important to identify populations of pathogens that are evolutionarily independent and thus ‘free’ to adapt to hosts and environments. Here, we investigated genetic variation in the globally distributed, highly invasive avian malaria parasite Plasmodium relictum , which has several distinctive mitochondrial haplotyps (cyt b lineages, SGS1, GRW11 and GRW4). The phylogeography of P. relictum was accessed using the highly variable nuclear gene merozoite surface protein 1 (MSP1), a gene linked to the invasion biology of the parasite. We show that the lineage GRW4 is evolutionarily independent of GRW11 and SGS1 whereas GRW11 and SGS1 share MSP1 alleles and thus suggesting the presence of two distinct species (GRW4 versus SGS1 and GRW11). Further, there were significant differences in the global distribution of MSP1 alleles with differences between GRW4 alleles in the New and the Old World. For SGS1, a lineage formerly believed to have both tropical and temperate transmission, there were clear differences in MSP1 alleles transmitted in tropical Africa compared to the temperate regions of Europe and Asia. Further, we highlight the occurrence of multiple MSP1 alleles in GRW4 isolates from the Hawaiian Islands, where the parasite has contributed to declines and extinctions of endemic forest birds since it was introduced. This study stresses the importance of multiple independent loci for understanding patterns of transmission and evolutionary independence across avian malaria parasites.

Ecography↗