American Goldfinches Research Articles

The Effects of Native Grass and Shrub Restoration on Nesting and Fall Migrant Songbirds in Central Kentucky

While native grass and shrub restoration is often promoted for bird conservation, evaluations are necessary to understand the effects of habitat change on songbird vital rates and migratory stopover use. We evaluated the effects of native vegetation restoration on the species richness, productivity, and capture rate of breeding and fall migrating songbirds at the Shaker Village of Pleasant Hill, in central Kentucky, USA. From 2009 to 2022, we conducted constant effort mist netting, resulting in 8418 captures of 110 bird species. In 2012–2013, we implemented management in the study area, which began as an old field, to restore native grasses, forbs, and shrubs. Effects on the vital rates of breeding species included higher Spizella pusilla (field sparrow) and Spinus tristis (American goldfinch) productivity post restoration. Restoration of native vegetation also led to significantly higher fall capture rates for pooled cohorts of both long-distance and medium-distance migrants. Our results demonstrate that the restoration and management of native vegetation can enhance stopover habitats for fall migrating songbirds including neotropical migrants and the field sparrow, a common bird in steep decline. We recommend prioritizing areas for native grass and shrub restoration that initially lack structural heterogeneity (a well-developed grass component with diverse forbs and interspersed shrubs).

The genetic consequences of historic climate change on the contemporary population structure of a widespread temperate North American songbird

Studies of widely distributed species can inform our understanding of how past demographic events tied to historic glaciation and ongoing population genetic processes interact to shape contemporaneous patterns of biodiversity at a continental scale. In this study, we used whole-genome resequencing to investigate the current population structure and genetic signatures of past demographic events in the widespread migratory American goldfinch (Spinus tristis). Phylogenetic relationships inferred from whole mitochondrial genomes were poorly resolved. In contrast, a genome-wide panel of > 4.5 million single nucleotide polymorphisms (SNPs) strongly supported the existence of eastern and western populations separated by western mountain ranges and additional population structuring within the western clade. Demographic modeling estimated that the eastern and western populations diverged approximately one million years ago, and both populations experienced subsequent population bottlenecks during the last glacial period. Species distribution models showed a severe contraction of suitable habitat for the American goldfinch during this period, with predicted discontinuities that are consistent with multiple, isolated glacial refugia that coincide with present-day population structure. Low overall genetic differentiation between the eastern and western populations (FST ∼ 0.01) suggests ongoing gene flow accompanied divergence, and individuals with admixed genomic signatures were sampled along a potential contact zone. Nevertheless, outlier SNPs were identified near genes associated with feather color, song, and migratory behavior and provide strong candidates for further study of the mechanisms underlying reproductive isolation and speciation in birds.

Gene expression variation in geographically diverse populations of two North American songbird species

The range distributions of many bird species cover extensive geographic distances, exposing each local population to unique ecological challenges. Understanding the molecular basis of how species adapt to diverse habitats across their geographic range is crucial for identifying populations at risk and implementing effective conservation strategies. In this study, we employed two passerine species, the black-capped chickadee (Poecile atricapillus) and the American goldfinch (Spinus tristis), which are widely distributed across North America. This study focused on examining changes in gene expression within their distinct populations inhabiting diverse habitats across various geographical locations. A comparative transcriptomic study was conducted on wild-caught birds from two geographically separate locations, Boston, Massachusetts, and Kent, Ohio, characterized by considerable annual variability in winter severity. We tested the hypothesis that populations of both species in Kent and Boston would show differential gene expression patterns in their brains in response to unique local environmental conditions. Analyzing the differentially expressed genes (DEGs) in black-capped chickadees revealed associations with neural processes such as the generation and maintenance of neurons, activity-dependent plasticity, and cognitive ability. Many of these genes were linked to brain variation in chickadee populations related to spatial cognition associated with food caching. We also compared changes in gene expression levels with coding sequence variability to explore the underlying basis of differential gene expression patterns. We tested the hypothesis that expression differences are driven by underlying genetic variation. A population genetic analysis on transcriptome data from both species revealed no highly divergent genetic variants (single nucleotide polymorphisms or SNPs) in the coding regions of genes identified as differentially expressed. However, some of the DEGs themselves were transcription factors or regulatory molecules, as were some of the genes with highly divergent SNPs. These findings suggest that the genetic architecture underlying the differential gene expression patterns is mostly regulatory rather than protein-coding changes.

Habitat associations and conservation opportunities for priority birds on small, diversified farms in the northeastern USA

Abstract Although the impacts of intensive agriculture on biodiversity and strategies for mitigating these effects have been widely described, small-scale, diversified farms and the opportunities they present for bird conservation have been less thoroughly examined. This omission is potentially significant, because this form of agriculture represents a growing sector of the industry in the populous northeastern USA, and the diverse habitats on these farms contrast with larger, structurally homogeneous intensive agriculture. To evaluate bird-habitat associations and conservation opportunities for supporting species of conservation concern on these small, diversified farms, we conducted avian point count and vegetation surveys across 23 farms in western Massachusetts during the summers of 2017 and 2018. We used Poisson-binomial mixture models and canonical correspondence analysis to assess the effects of a suite of microhabitat-, field- and landscape-scale (1 km buffer around the field) variables on the abundance of bird species. Our results confirmed that shrubland birds, a group of species of elevated conservation concern, accounted for 52% of the total observations, including song sparrow (Melospiza melodia), gray catbird (Dumatella carolinensis), common yellowthroat (Geothlypis trichas) and American goldfinch (Spinus tristis). Species–habitat relationships were diverse; however, smaller field sizes, and increased cover of tall, dense, woody or non-productive vegetation types were associated with higher abundance of shrubland species as well as lower abundance of crop pests such as European starling (Sturnus vulgaris) and house sparrow (Passer domesticus). These findings support the hypothesis that small, diversified farms are supporting birds of high conservation concern, and we provide species-specific guidelines for farmers interested in conserving birds on their land.

Molecular identification and phylogenetic analysis of Macrorhabdus ornithogaster based on the 18S rRNA gene in companion birds of Tehran, Iran.

Macrorhabdus ornithogaster (MO) is an infectious yeast which can cause acute gastric disturbances in birds. It has a worldwide distribution with a broad host-range of bird species. Molecular identification and phylogenetic analysis of MO based on the 18S rRNA gene in companion birds of Iran. A total of 54 stool samples were taken from birds (10 species) suspected of being infected. The presence of MO in collected stool samples was investigated using direct wet mount microscopy. Specific primers were designed to identify the MO 18S rRNA gene by using PCR. PCR products were sequenced and phylogenetic analysis was performed to determine the molecular diversity. The obtained results demonstrated that 44.44% and 59.26% of the samples were diagnosed positive based on the first and second specific primers, respectively. MO was detected in the feces of canary, goldfinch, budgerigar, toucan, and English budge. Phylogenetic analysis revealed that MO sequence data from canaries, finches, and goldfinches had homology with an MO isolated from a German zebra finch. Moreover, MOs from cockatiels, rosy faced love birds, and budgerigars had a high phylogenetic similarity with multiple references, including American budgerigar, Japanese cockatiel, European goldfinch, and German budgerigar. MO exists in many species of Iranian birds, including goldfinches, budgerigars, toucans, and English budgies. As indicated by phylogenetic and polymorphism data analysis, the newly designed specific primers spanning a large portion of 18S rRNA gene of MO, provides additional tool to detect and study the molecular diversity of MO.

Metabolic Profiling and Integration of Metabolomic and Transcriptomic Data From Pectoralis Muscle Reveal Winter-Adaptive Metabolic Responses of Black-Capped Chickadee and American Goldfinch

Seasonal changes, such as alterations in food availability or type and cold conditions, present challenges to free-living birds living in highly seasonal climates. Small birds respond to such challenges through seasonal metabolic flexibility, which better matches seasonal metabolic phenotypes to environmental conditions and can improve fitness. To better understand the mechanistic basis of this metabolic flexibility, we conducted a large-scale metabolic profiling of pectoralis muscle in black-capped chickadees (Poecile atricapillus) and American goldfinches (Spinus tristis), which are small, year-round bird species of temperate-zones. We analyzed muscle samples using non-biased, global metabolomics profiling technology based on UHLC/MS/MS2 platforms. A total of 582 metabolites was characterized for summer and winter season samples. Chickadees showed greater seasonal separation of global metabolite profiles than goldfinches, which is consistent with previous transcriptomic studies of pectoralis muscle in these two species. Reduced levels of amino acids during winter occurred in both species and might reflect decreasing dietary protein intake, amino acid shuttling to other pathways for thermogenesis and/or elevated rates of protein turnover in the pectoralis muscle. Concomitant decreased abundances in tricarboxylic acid cycle (TCA) metabolites suggest faster cycling of the oxidative phosphorylation pathway in winter to meet the metabolic demands of thermogenesis. Accordingly, chickadees displayed shifts toward lipid oxidation in winter, whereas goldfinches showed winter declines in ketone bodies, which suggests increased energy demand or subtle changes in substrate availability. Beyond the winter-specific changes in metabolite abundances, integration of the metabolomic and the transcriptomic data revealed a landscape of gene–metabolite associations related to the winter-adaptive metabolic response. This landscape of gene–metabolite pairs was overrepresented by pathways associated with transport of small molecules, metabolism of amino acids and derivatives, activation and biosynthesis of fatty acid derivatives, and biosynthesis and metabolism of nicotinate and nicotinamide derivatives. Collectively, our results suggest that increased levels of NADH and its derivatives in the pectoralis muscle are a potential novel mechanism for increasing winter metabolic output, fueled by lipids, for thermogenesis during winter.

Bird predation and landscape context shape arthropod communities on broccoli

Abstract Birds increase crop yields via consumption of pests in some contexts but disrupt pest control via intraguild predation in others. Landscape complexity acts as an inconsistent mediator, sometimes increasing, decreasing, or not impacting pest control. Here, we examined how landscape context and seasonal variation mediate the impact of birds on arthropod pests and natural enemies, leaf damage, and yields of broccoli (Brassica oleracea) on highly diversified farms that spanned the USA west coast. Our study had two complementary components: a bird exclusion experiment and molecular diet analysis of 357 fecal samples collected from the most commonly captured bird species that also foraged in Brassica fields—American Goldfinch (Spinus tristis), American Robin (Turdus migratorius), Savannah Sparrow (Passerculus sandwichensis), Song Sparrow (Melospiza melodia), and White-crowned Sparrow (Zonotrichia leucophrys). Bird access yielded higher, rather than lower, numbers of pest aphids and increased their parasitism, while no other arthropods examined were consistently impacted. Independent of bird presence, percent natural cover in the landscape sometimes increased and sometimes decreased densities of arthropods in the mid-growth period, with diminishing impacts in the late-growth period. Herbivore feeding damage to broccoli leaves decreased with increasing amounts of natural land cover and in the late-growth period. Molecular diet analysis revealed that Brassica pests and predatory arthropods were relatively uncommon prey for birds. Landscape context did not alter the prey items found in bird diets. Altogether, our bird-exclusion experiment and molecular diet analysis suggested that birds have relatively modest impacts on the arthropods associated with broccoli plantings. More broadly, the limited support in our study for net natural pest control services suggests that financial incentives may be required to encourage the adoption of bird-friendly farming practices in certain cropping systems.

Which Bird Species Groups Use Highway Roadside Verges and Why?

Highway roadside verges (HRV) provide supplemental habitat for birds in intensive agricultural and suburban landscapes where the natural habitats are rapidly disappearing. The purpose of this study was to document the behavior of breeding bird species using the vegetation maintenance units (green shoulders, embankments, ditches, and banks) of HRV in 3 typical rural landscapes of southern Quebec, Canada. We observed the behavior of 722 individuals of 21 bird species. The most abundant ones (especially Sturnus vulgaris [European Starling] and Agelaius phoeniceus [Red-winged Blackbird]) foraged in the green shoulders, while others (such as Melospiza melodia [Song Sparrow], Spinus tristis [American Goldfinch], and Geothlypis trichas [Common Yellowthroat]) travelled or nested in the low vegetation in ditches and on the banks. Omnivorous species forage in the green shoulders and used the banks and ditches mainly for nesting-related behaviors, just like the few insectivorous species observed. The granivorous species were almost absent from studied HRV. Ground-foraging species used the shoulders to feed but nested in ditches and banks. Species foraging in low vegetation foraged mainly on the banks and used the ditches more for travelling. Reducing the mowing frequency of these 2 maintenance units would likely result in an increase in the vegetation cover and would thus provide additional nesting and foraging habitat for the species we recorded, 67% of which show a stable or declining population in North America.

Evaluating the accuracy and biological meaning of visits to RFID-enabled bird feeders using video.

Radio‐frequency identification (RFID) technology has gained popularity in ornithological studies as a way to collect large quantities of data to answer specific biological questions, but few published studies report methodologies used for validating the accuracy of RFID data. Further, connections between the RFID data and the behaviors of interest in a study are not always clearly established. These methodological deficiencies may seriously impact a study's results and subsequent interpretation. We built RFID‐equipped bird feeders and mounted them at three sites in Tompkins County, New York. We deployed passive integrated transponder tags on black‐capped chickadees, tufted titmice, and white‐breasted nuthatches and used a GoPro video camera to record the three tagged species at the feeders. We then reviewed the video to determine the accuracy of the RFID reader and understand the birds’ behavior at the feeders. We found that our RFID system recorded only 34.2% of all visits by tagged birds (n = 237) and that RFID detection increased with the length of a visit. We also found that our three tagged species and two other species that visited the feeders, American goldfinch and hairy woodpecker, retrieved food in 79.5% of their visits. Chickadees, titmice, nuthatches, and woodpeckers spent, on average, 2.3 s at feeders to collect one seed per visit. In contrast, goldfinches spent an average of 9.0 s at feeders and consumed up to 30 seeds per visit. Our results demonstrate the importance of confirming detection accuracy and that video can be used to identify behavioral characteristics associated with an RFID reader's detections. This simple—yet time‐intensive—method for assessing the accuracy and biological meaning of RFID data is useful for ornithological studies but can be used in research focusing on various taxa and study systems.

Using faecal metabarcoding to examine consumption of crop pests and beneficial arthropods in communities of generalist avian insectivores

Generalist insectivorous birds can provide ecosystem services in agricultural landscapes by consuming arthropod pests, or they can provide disservices when they consume beneficial arthropods. To examine bird impacts on arthropod communities, including pest control services, we need to know which arthropods birds commonly consume. Faecal metabarcoding is an emerging technique that can be used to identify prey from faecal samples, often to the species level. We used faecal metabarcoding to study diets of birds inhabiting the ecotone between soybean fields and adjacent grasslands in a largely agricultural landscape in Illinois, USA, during the summer of 2017. Whereas previous studies have used faecal metabarcoding to compare bird diets among species or among capture sites, we analysed samples from multiple species within a community at replicate sites. We collected and sequenced DNA from 132 faecal samples from 25 bird species captured at six sites. We found that birds consumed an extremely large and varied diet that differed among both species and sites, suggesting that birds were consuming prey opportunistically as available at each site. Of the nine most commonly detected prey species, three are known pests of soybeans. Bird diets also contained significantly more species of herbivorous prey than natural enemies. Finally, we discovered that American Goldfinches Spinus tristis, a highly granivorous species, may consume arthropods more frequently than expected and thus may provide ecosystem services in agricultural landscapes. Our study demonstrates that birds within this system consume a large variety of prey, suggesting that they may be able to respond quickly to pest outbreaks and contribute to agricultural resiliency.

Seasonal Patterns of Fat Deposits in Relation to Migratory Strategy in Facultative Migrants

Physiological preparations for migration generally reflect migratory strategy. Migrant birds fuel long-distance flight primarily with lipids, but carrying excess fuel is costly; thus, the amount of fat deposited prior to departure often reflects the anticipated flight duration or distance between refueling bouts. Seasonal pre-migratory deposition of fat is well documented in regular seasonal migrants, but is less described for more facultative species. We analyze fat deposits of free-living birds across several taxa of facultative migrants in the songbird subfamily Carduelinae, including house finches (Haemorhous mexicanus), American goldfinches (Spinus tristis), pine siskins (Spinus pinus) and four different North American ecotypes of red crossbills (Loxia curvirostra), to evaluate seasonal fat deposition during facultative migratory periods. Our data suggest that the extent of seasonal fat deposits corresponds with migratory tendency in these facultative taxa. Specifically, nomadic red crossbills with a seasonally predictable annual movement demonstrated relatively large seasonal fat deposits coincident with the migratory periods. In contrast, pine siskins, thought to be more variable in timing and initiation of nomadic movements, had smaller peaks in fat deposits during the migratory season, and the partial migrant American goldfinch and the resident house finch showed no peaks coincident with migratory periods. Within the red crossbills, those ecotypes that are closely associated with pine habitats showed larger peaks in fat deposits coincident with autumn migratory periods and had higher wing loading, whereas those ecotypes associated with spruces, Douglas-fir and hemlocks showed larger peaks coincident with spring migratory periods and lower wing loading. We conclude that population averages of fat deposits do reflect facultative migration strategies in these species, as well as the winter thermogenic challenges at the study locations. A difference in seasonal fattening and wing loading among red crossbill ecotypes is consistent with the possibility that they differ in their migratory biology, and we discuss these differences in light of crossbill reproductive schedules and phenologies of different conifer species.

High egg rejection and low aggressive responses of Mountain Bluebirds (Sialia currucoides) toward Brown-headed Cowbirds (Molothrus ater)

Hosts of brood parasitic Brown-headed Cowbirds (Molothrus ater) have acquired a suite of behavioral responses against them, including egg rejection and nest defense. Several cavity-nesting species have been shown to exhibit egg rejection, including the Mountain Bluebird (Sialia currucoides). Previous work reported egg rejection rates as low as 20%, under the assumption that they may instead be relying heavily on aggressive interactions to defend their nests from parasitism. In the present study, we evaluated the egg rejection and aggression behaviors of a population of Mountain Bluebirds in western Montana. Results indicate a higher rate of rejection than previously documented, with model cowbird eggs rejected in over 40% of trials (n = 37), compared with 5% rejection of mimetic eggs. In contrast, we found little aggressive response by Mountain Bluebirds toward both an adult cowbird model and a nonthreatening American Goldfinch (Carduelis tristis) model. Aggression patterns were consistent between sexes, with the most common behaviors including sitting and watching from within 5 m and flying past the models (n = 21). Hovering above the model was observed on a few occasions, and physical contact by bluebirds happened on only 3 occasions toward the goldfinch model. In summary, Mountain Bluebirds in western Montana showed relatively high rates of cowbird egg rejection but little aggressive response toward adult heterospecific nest intruders.

Late laying by a Brown-headed cowbird, in an American goldfinch nest

Late laying by a Brown-headed cowbird, in an American goldfinch nest

The Frog Pond

The Frog Pond Campbell McGrath (bio) 1 Late July and the grass rises waist-high, leonine,straw and russet running down the little hillside meadowto the frog pond where the night egret lurksbut the frogs are silent now, hiddenin the weeds from the sun and other unmerciful eyes.Across the road the cornfields are lush and delectablethough the milk cows that blanketed the hillsides are long gone,it’s become a corporate business, dairy farming,and the old family pastures have been repossessed by trees.The forest is a voracious, green-leafed glacier.And the frog pond gleamsin sunlight, a mirror the color of oak roots,a slab of rain-wet shale lightly sheathed in moss.Not yet time to swim, but it awaits. After the rain the pond smells like bird seed.Or maybe that’s seed-dust from the feeder on my hands,I’ve refilled it so the blue jay can chase away the cardinalswhile the cheeping songbirds steal whatever spillsor overflows. Bird seed and copper pennies.Soil, minerals, lemon, cedar. Pine Sol cleanser—gray water in the bucket after mopping the cabin floor!Of course, these are all smells from my childhood,so perhaps I am merely remembering the tasteof Poconos lake water and associating it forwards,or back? Nostalgia is time’s double agent.At least it does not smell like Hawaiian Punch. Not yet.The pond is home to a pair of plump golden grass carpand a swarm of little mud-colored minnowsand hosts of gorgeous black-and-violet dragonfliesand vivid, orange-red damselflies. The slenderest damselsraft around on twigs and leaves, one per vessel,and zoom away as I approach them, eye to eye.Sometimes one lands on my head, mistaking mefor what—a lotus blossom? A moose? A golden carp? [End Page 157] Jumping in: sound of water, slap of impact,liquid membrane against my own, skin to skin.The pond is a layer cake, warm as a sun-heated tubat the surface, cool and murky in the middle,while the spring-fed depths remain bone cold,chthonic, unyielding as granite. It starts to rain again.Drops pock the surface and I try to catch them in my mouth.Floating on my back I watch one final cloudcoming over the mountain after the front has galloped past,leaving the crowns of the trees a rough silver-grayin storm-slanted light. Poor little cloud, it is shrinkingaway, smaller and smaller, my sheepish straggler,down to the vanishing point—and gone,atoms dispersed into the atmosphere, unlamented,and unrecorded, I suppose, by any eyes but mine. 2 Before lunch a flock of wild turkeys traipse through the yardlike a posse of tiny dinosaurs, patrolling stealthilythrough the tall grass, head up, head down,gangling, straggle-feathered, dingy but not undignified.A rafter of turkeys, some would have it, rather than a flock,though of course those compound nouns are a crockinvented to delight weakling imaginations,a murder of crows, an exaltation of malarkey—this was a pure-bred American turkey mob,seven or eight gray-scale chicks able to vanish instantlyinto the tawny meadow grass at the slightest sound,like special ops forces on a recon mission.Four or five middling ones, the largest alone out front—is it a harem and only one male, is that how it works?Naughty birds. Pecking and neck-bobbling,obeying their arcane protocols,they traverse the hill and disappear into the woods. “Bird TV,” Elizabeth calls it, watching our airy neighborsfrom the big sliding windows of the sunroom,paired doves, the great blue heron, vultures circling the ridge.Yesterday we noticed three small, eye-catching birdsin the meadow, their wings the bright yellowof October maple leaves, their identity a mysteryuntil one perched carefully atop a bristling purple thistle, [End Page 158] exactly as described in the Audubon Guidefor the American Goldfinch. So there it is. And there they go,swooping to the branches of the mulberry tree,where, some afternoons, the imperturbable woodchucktrundles from his streamside thicket to gobble fallen fruit...

Imidacloprid Poisoning of Songbirds Following a Drench Application of Trees in a Residential Neighborhood in California, USA.

In March 2017, 26 American goldfinches (Spinus tristis) were found dead following a drench application of imidacloprid in California (USA). Identical seed fragments were present in the digestive tracts. Imidacloprid was detected in 4 separate pooled samples from 18 birds, in crop/gizzard contents (4.8 ± 1.3 ppm; range 2.2–8.5 ppm) and liver tissues (3.9 ± 0.6 ppm; range 2.1–4.8 ppm). We suspect that fallen elm (Ulmus sp.) seeds were contaminated with imidacloprid during the drench application and subsequently ingested, resulting in acute toxicity and death. Environ Toxicol Chem 2019;38:1724–1727. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Isospora coronoideae n. sp. (Apicomplexa: Eimeriidae) from the Australian raven (Corvus coronoides) (Passeriformes: Corvidae) (Linnaeus, 1758) in Western Australia.

A new Isospora (Apicomplexa: Eimeriidae) species is described from an Australian raven (Corvus coronoides) in Western Australia. Sporulated oocysts (n = 21) are ovoid, 21.2 (18.4-23.9) μm in length and 18.8 (16.9-20.6) μm in width, with a shape index of 1.13. The bi-layered oocyst wall is smooth and colourless, 1.2μm thick. A polar granule and oocyst residuum is present, but the micropyle is absent. The sporocysts are ovoid-shaped, 16.3 (13.7-18.9) × 10.7 (8.4-12.9) μm, with a shape index (length/width) of 1.52. Stieda and substieda bodies are present, the Stieda body being small and hemidome-shaped and the substieda being indistinct. Each sporocyst with four vermiform sporozoites arranged head to tail. The sporozoites are crescent-shaped, 9.0 (8.9-9.2) × 2.7 (2.3-3.0) μm, with a shape index (length/width) of 3.33. The sporocyst residuum is present. The isolated oocysts had different morphological characteristics when compared with all known Isospora spp. The coccidian parasite was analysed at the 18S and 28S ribosomal RNA and the mitochondrial cytochrome oxidase (COI) loci. At the 18S locus, I. coronoideae n. sp. exhibited 98.9% similarity to I. neochmiae from a captive-bred red-browed finch (KT224380) and Isospora sp. from domestic pigeons (Columba livia domestica) (AB757860), 98.5% similarity to I. gryphoni (AF080613) from an American goldfinch and 98.3% similarity to I. manorinae (KT224379) from a yellow-throated miner. At the 28S locus, it exhibited 95.4% and 94.8% similarity to I. manorinae (KT224381) and I. anthochaerae (KF766053), respectively. At the COI locus, it exhibited 99.8% and 99.7% similarity to I. butcherae (KY801687) and I. neochmiae (KT224378), respectively. Based on morphological and molecular data, this isolate is a new species of Isospora, which is named Isospora coronoideae n. sp. after its host, the Australian raven (Corvus coronoides) (Passeriformes: Corvidae) (Linnaeus, 1758).

Experimental Infection and Transmission of Newcastle Disease Vaccine Virus in Four Wild Passerines.

Our prior work has shown that live poultry vaccines have been intermittently isolated from wild birds sampled during field surveillance studies for Newcastle disease virus (NDV). Thus, we experimentally investigated the susceptibility of four native agriculturally associated wild bird species to the NDV LaSota vaccine and evaluated the shedding dynamics, potential transmission from chickens, and humoral antibody responses. To test susceptibility, we inoculated wild-caught, immunologically NDV-naïve house finches (Haemorhous mexicanus; n = 16), brown-headed cowbirds (Molothrus ater; n = 9), northern cardinals (Cardinalis cardinalis; n = 6), and American goldfinches (Spinus tristis; n = 12) with 0.1 ml (106.7 mean embryo infectious doses [EID50/ml]) of NDV LaSota vaccine via the oculo-nasal route. To test transmission between chickens and wild birds, adult specific-pathogen-free white leghorn chickens were inoculated similarly and cohoused in separate isolators with two to five wild birds of the species listed above. This design resulted in three treatments: wild bird direct inoculation (five groups) and wild bird exposure to one (two groups) or two inoculated chickens (six groups), respectively. Blood and oropharyngeal and cloacal swabs were collected before and after infection with the live vaccine. All wild birds that were directly inoculated with the LaSota vaccine shed virus as demonstrated by virus isolation (VI). Cardinals were the most susceptible species based on shedding viruses from 1 to 11 days postinoculation (dpi) with titers up to 104.9 EID50/ml. Although LaSota viruses were shed by all inoculated chickens and were present in the drinking water, most noninoculated wild birds cohoused with these chickens remained uninfected for 14 days as evidenced by VI. However, one American goldfinch tested positive for vaccine transmission by VI at 7 dpi and one house finch tested positive for vaccine transmission by real-time reverse-transcription PCR at 13 dpi. Only one directly inoculated cowbird (out of three) and two cardinals (out of two) developed NDV-specific hemagglutination inhibition antibody titers of 16, 16, and 128, respectively. No clinical signs were detected in the chickens or the wild birds postinoculation.

Responses of early-successional songbirds to a two-stage shelterwood harvest for oak forest regeneration

BackgroundThe early stage of forest succession following disturbance is characterized by a shift in songbird composition as well as increased avian richness due to increased herbaceous growth in the forest understory. However, regeneration of woody species eventually outcompetes the herbaceous understory, subsequently shifting vegetation communities and decreasing availability of vital foraging and nesting cover for disturbance-dependent birds, ultimately resulting in their displacement. These early stages following forest disturbance, which are declining throughout the eastern United States, are ephemeral in nature and birds depend on such disturbances for nesting and other purposes throughout their lives.MethodsWe investigated the use of a two-stage shelterwood method to manage long-term persistence of seven early successional songbirds over a 13-year period in an upland hardwood forest within the southern end of the mid-Cumberland Plateau in the eastern United States.ResultsCanopy and midstory gaps created after initial harvest were quickly exploited by tree growth and canopy cover returned to these areas, accelerating the displacement of early-successional species. Woody stem densities increased substantially following stage two harvest as advanced tree regeneration combined with the re-opening of the overstory layer increased resource competition for early-successional plants in the understory. Carolina Wren (Thryothorus ludovicianus), Eastern Towhee (Pipilo erythrophthalmus), Indigo Bunting (Passerina cyanea), and Yellow-breasted Chat (Icteria virens) were characterized by immediate increases following initial harvest in 2001; while the American Goldfinch (Spinus tristis), Prairie Warbler (Setophaga discolor), and White-eyed Vireo (Vireo griseus) did not show an immediate response. Stage two harvest in 2011 rejuvenated vegetation which benefitted focal species, with six of seven species showing increases in densities between 2010 and 2012.ConclusionThe two-stage shelterwood method created conditions advantageous to early-successional birds by helping to re-establish understory vegetation through periodic disturbance to the canopy layer. This method provides evidence that early-successional species can be managed long-term (> 15 years) while using relatively small spatial disturbance through the two-stage shelterwood method.

Avian Feeding on Seed of the Exotic OrnamentalLagerstroemia indica(Crapemyrtle)

The ornamental plant Lagerstroemia indica (Crapemyrtle) was introduced to American gardens before 1796, but little is known about its use as a food resource by avian species. Local wintering populations of Spinus tristis (American Goldfinch), Junco hyemalis (Dark-eyed Junco), and Haemorhous mexicanus (House Finch) feed heavily on Crapemyrtle seeds, and I observed 5 additional bird species occasionally extracting seeds from dehiscent capsules in Fairfax County, VA. Planted and naturalized Crapemyrtle may be an important food resource for finches and sparrows in southeastern US.

Endemic infection of the common mynah Acridotheres tristis with Trichomonas gallinae the agent of avian trichomonosis.

Avian trichomonosis is an architypal disease of wild columbids and those birds that predate them. Increasingly though, it has been reported in passerines; a recent and ongoing epidemic in the chaffinches and greenfinches of Europe and outbreaks amongst house finches, American goldfinches and purple finches in North America. The parasite, Trichomonas gallinae, causes lesions in the upper respiratory tract which can cause mortality associated with dehydration and emaciation. This paper reports for the first time, the widespread, endemic and often asymptomatic infection of common mynah (Acridotheres tristis) around the Faisalabad District, Pakistan. Parasite typing was used to investigate the potential for transmission among the frequently sympatric species. Type C parasites were found in mynah, and while this is analagous to the pandemic finch strain which is Type A, it is the first known example of passerine infections of this parasite genotype. Subtype analysis showed the strain to be C4 a subtype which has a widespread distribution in columbids.