| variation at the major histocompatibility complex in savannah sparrows. | the class i and class ii genes of the major histocompatibility complex (mhc) encode dimeric glycoproteins responsible for eliciting the adaptive immune response of vertebrates. recent work with birds suggests that the number, size, and arrangement of these genes can differ markedly across species, although the extent of this variation, and its causes and consequences, are poorly understood. we have used a 157-base-pair (bp) portion of the second exon of a class ii b gene to probe the mhc in a fr ... | 2002 | 12030987 |
| the use of digital photos to assess visual cover for wildlife in rangelands. | grassland vegetation can provide visual cover for terrestrial vertebrates. the most commonly used method to assess visual cover is the robel pole. we test the use of digital photography as a more accurate and repeatable method. we assessed the digital photography method on four forage grassland species (pseudoroegneria spicata, festuca campestris, poa pratensis, achnatherum richardsonii). digital photos of 2-dimensional cutout silhouettes of three bird species sharp-tailed grouse, western meadow ... | 2010 | 20226585 |
| four new species of aulonastus kethley, 1970 (acari: syringophilidae) from north american passerines. | four new species belonging to aulonastus kethley, 1970 (acari: prostigmata: syringophilidae), which are found inside the quills of body feathers of north american passerines (aves: passeriformes), are described and figured: a. emberizicus n. sp. from ammodramus savanarum (gmelin) (emberizidae) (type-host) in texas, zonotrichia atricapilla (gmelin) (emberizidae) in california and passerculus sandwichensis (gmelin) (emberizidae) in texas; a. euphagus n. sp. from euphagus cyanocephalus (wagler) (ic ... | 2010 | 20437219 |
| wild birds, a source of reticuloendotheliosis virus infection for the endangered attwater's prairie-chicken ( tympanuchus cupido attwateri)? | reticuloendotheliosis virus (rev) infects a wide range of avian species. since 1998, when it was first reported in a captive flock of the endangered attwater's prairie-chicken ( tympanuchus cupido attwateri; apc), rev has plagued apc recovery efforts. while rev frequently occurs in captive bird flocks throughout the world, including commercial poultry, the reservoir for initial infection of flocks is poorly understood. from 2008-2016, 412 blood samples and 216 liver samples collected from 32 spe ... | 2017 | 28192047 |
| a phylogenetic analysis of the emberizid sparrows based on three mitochondrial genes. | previous molecular phylogenetic studies have examined the taxonomic relationships among a number of typical emberizid sparrow genera. to help clarify these relationships, we sequenced a 1673 base pair fragment for the complete sequence of three mitochondrial genes: adenosine triphosphatase (atp8 and atp6) and cytochrome oxidase subunit iii (coiii) for 38 sparrow species, along with passerina amoena (cardinalidae) and piranga ludoviciana (thraupidae) which were selected as the outgroups. our anal ... | 2003 | 12967606 |
| effects of shallow natural gas well structures and associated roads on grassland songbird reproductive success in alberta, canada. | grassland songbird populations across north america have experienced dramatic population declines due to habitat loss and degradation. in canada, energy development continues to fragment and disturb prairie habitat, but effects of oil and gas development on reproductive success of songbirds in north american mixed-grass prairies remains largely unknown. from 2010-2012, in southeastern alberta, canada, we monitored 257 nests of two ground-nesting grassland songbird species, savannah sparrow (pass ... | 2017 | 28355241 |
| grassland songbird survival and recruitment in agricultural landscapes: implications for source-sink demography. | population growth and decline are particularly sensitive to changes in three key life-history parameters: annual productivity, juvenile survival, and adult survival. however, for many species these parameters remain unknown. for example, although grassland songbirds are imperiled throughout north america, for this guild, only a small number of studies have assessed these parameters. from 2002 to 2006, in the agricultural landscape of the champlain valley of vermont and new york, usa, we studied ... | 2008 | 18705380 |
| grassland songbirds in a dynamic management landscape: behavioral responses and management strategies. | in recent decades, earlier and more frequent harvests of agricultural grasslands have been implicated as a major cause of population declines in grassland songbirds. from 2002 to 2005, in the champlain valley of vermont and new york, usa, we studied the reproductive success of savannah sparrows (passerculus sandwichensis) and bobolinks (dolichonyx oryzivorus) on four grassland treatments: (1) early-hayed fields cut before 11 june and again in early- to mid-july; (2) middle-hayed fields cut once ... | 2006 | 17205901 |
| effects of granular formulations of terbufos and fonofos applied to cornfields on mortality and reproductive success of songbirds. | : this field study used a precise method of assessing effects of insecticides on bird populations by establishing a marked population before application and determining survival rates of known individuals after application of the insecticides. we investigated the effects of two organophosphate granular insecticides applied to cornfields in southwestern ontario to combat the corn rootworm (diabrotica spp.). nine control fields and 11 treated fields, six of which were treated with fonofos (dyfonat ... | 1995 | 24197620 |
| the development of migratory orientation mechanisms. | recent experimental studies (since ca. 1985) on the ontogeny of orientation mechanisms in migratory birds are reviewed. the processes and interactions are synthesized into a framework that may help identify critical research questions. birds that grow up in the earth's magnetic field develop the ability to perform appropriate migratory orientation, even in the absence of any experience with relevant visual cues. in two species, large changes in direction during the course of migration seem to be ... | 1991 | 1838514 |
| doing more with less: removing trees in a prairie system improves value of grasslands for obligate bird species. | grassland birds endemic to the northern great plains have declined faster and more severely than any other avian guild on the continent. remaining prairie fragments that sustain breeding populations are continually converted to a disturbed state, or degraded by fragmentation. planted tree rows (shelterbelts) in prairie landscapes are a prominent feature and have been implicated in propagating negative edge effects on breeding birds, perhaps through harboring a diverse suite of nest predators. we ... | 2017 | 28460323 |
| renal anatomy in sparrows from different environments. | the renal anatomy of three species of sparrows, two from mesic areas, the house sparrow (passer domesticus) and song sparrow (melospiza melodia), and one salt marsh species, the savannah sparrow (passerculus sandwichensis) was examined. electron microscopy was used to describe the ultrastructure of the nephron. in addition, stereology was used to quantify the volumes of cortex, medulla, and major vasculature of the kidneys, and the volumes and surface areas occupied by individual nephron compone ... | 2000 | 10681473 |
| validation of the doubly labeled water technique for measuring energy metabolism in starlings and sparrows. | i have tested the idea that doubly labeled water (dlw) can accurately predict co2 production in savannah sparrows, song sparrows, white-throated sparrows, starlings, and a single house sparrow by comparing dlw estimates with those obtained simultaneously by capturing expired co2 in ascarite. in addition i used the energy balance method to see if metabolic rates generated from dlw measurements accurately reflected the actual metabolic rates of these birds. i found close agreement in dlw and the g ... | 1985 | 2858313 |
| humerus length and foramen magnum area as indicators of size in birds. | in a group of birds (passerines and non-passerines) body weight was found to be highly correlated with the length of the humerus and with the area of the foramen magnum. in addition, body weight was highly correlated with humerus length in 58 specimens of streak-necked fly-catcher, mionectes striaticollis, suggesting a possible use of this measurement to estimate body weight of individuals in a single species. body weight was not correlated with foramen magnum area in 25 specimens of savannah sp ... | 1985 | 3993976 |
| conventional oil and natural gas infrastructure increases brown-headed cowbird (molothrus ater) relative abundance and parasitism in mixed-grass prairie. | the rapid expansion of oil and natural gas development across the northern great plains has contributed to habitat fragmentation, which may facilitate brood parasitism of ground-nesting grassland songbird nests by brown-headed cowbirds (molothrus ater), an obligate brood parasite, through the introduction of perches and anthropogenic edges. we tested this hypothesis by measuring brown-headed cowbird relative abundance and brood parasitism rates of savannah sparrow (passerculus sandwichensis) nes ... | 2017 | 28791134 |
| luminal morphology of the avian lower intestine: evidence supporting the importance of retrograde peristalsis for water conservation. | tissue from the lower intestine of two species of sparrow, the house sparrow passer domesticus and savannah sparrow passerculus sandwichensis was sectioned in an unbiased manner and examined quantitatively using stereology. the tissue was processed for light microscopy, and scanning and transmission electron microscopy to examine the extent to which microvilli enhanced the epithelial surface area of the cecae, rectum, and coprodeum. parameters measured included individual microvillus surface are ... | 2001 | 11455538 |
| time as tyrant: the minute, hour and day make a difference for corticosterone concentrations in wild nestlings. | the hypothalamic-pituitary-adrenal (hpa) axis has been studied extensively in adults, but the hpa axis in early life is not well characterized, and there is an immense amount of unexplained variation in glucocorticoid levels during early life, especially in wild animals. to characterize population-wide natural variation in early-life hpa axis function, we compared plasma corticosterone levels (at baseline and after 30min acute restraint-stress) from seven-day-old nestlings (n=123) from a free-li ... | 2017 | 28577897 |
| local density regulates migratory songbird reproductive success through effects on double-brooding and nest predation. | knowledge of the density-dependent processes that regulate animal populations is key to understanding, predicting, and conserving populations. in migratory birds, density-dependence is most often studied during the breeding season, yet we still lack a robust understanding of the reproductive traits through which density influences individual reproductive success. we used 27-yr of detailed, individual-level productivity data from an island-breeding population of savannah sparrows passerculus sand ... | 2017 | 28555872 |
| differential migration and the link between winter latitude, timing of migration, and breeding in a songbird. | patterns of connectivity between breeding and wintering grounds can have important implications for individual fitness and population dynamics. using light-level geolocators and stable hydrogen isotopes (δ(2)h) in feathers, we evaluated differential migration of savannah sparrows (passerculus sandwichensis) breeding on kent island in the bay of fundy, new brunswick, canada in relation to sex, age, and body size. based on geolocators recovered from 38 individuals between 2012 and 2014, the winter ... | 2016 | 26888571 |
| differential fall migratory routes of adult and juvenile ipswich sparrows (passerculus sandwichensis princeps). | island breeding birds present an ideal system for studying migratory movements in passerines because their populations are clearly demarcated, and individuals must depart on migration from a single location. the ipswich sparrow (paserculus sandwichensis princeps) is a subspecies of the savannah sparrow that breeds exclusively on sable island, nova scotia, canada and winters along the atlantic coast of north america. we used a network of 34 automated vhf telemetry receivers to track radio-tagged ... | 2016 | 26819707 |
| automated telemetry reveals age specific differences in flight duration and speed are driven by wind conditions in a migratory songbird. | given that winds encountered on migration could theoretically double or half the energy expenditure of aerial migrants, there should be strong selection on behaviour in relation to wind conditions aloft. however, evidence suggests that juvenile songbirds are less choosy about wind conditions at departure relative to adults, potentially increasing energy expenditure during flight. to date, there has yet to be a direct comparison of flight efficiency between free-living adult and juvenile songbird ... | 2015 | 26279850 |
| the effect of trait type and strength of selection on heritability and evolvability in an island bird population. | the heritability (h(2) ) of fitness traits is often low. although this has been attributed to directional selection having eroded genetic variation in direct proportion to the strength of selection, heritability does not necessarily reflect a trait's additive genetic variance and evolutionary potential ("evolvability"). recent studies suggest that the low h(2) of fitness traits in wild populations is caused not by a paucity of additive genetic variance (va ) but by greater environmental or nonad ... | 2014 | 25130048 |
| timing of breeding carries over to influence migratory departure in a songbird: an automated radiotracking study. | 1. determining how events interact across stages of the annual cycle is critical for understanding the factors that affect individual fitness. however, there is currently little information detailing how breeding events influence migratory behaviour. 2. using an automated digital telemetry array and an isolated island-breeding population of savannah sparrows passerculus sandwichensis, we provide the first direct evidence that the timing of breeding events carries over to influence the timing of ... | 2012 | 22471701 |
| early life events carry over to influence pre-migratory condition in a free-living songbird. | conditions experienced during development can have long-term consequences for individual success. in migratory songbirds, the proximate mechanisms linking early life events and survival are not well understood because tracking individuals across stages of the annual cycle can be extremely challenging. in this paper, we first use a 13 year dataset to demonstrate a positive relationship between 1(st) year survival and nestling mass in migratory savannah sparrows (passerculus sandwichensis). we als ... | 2011 | 22194925 |
| white-throated sparrows calibrate their magnetic compass by polarized light cues during both autumn and spring migration. | the interaction and hierarchy of celestial and magnetic compass cues used by migratory songbirds for orientation has long been the topic of an intense debate. we have previously shown that migratory savannah sparrows, passerculus sandwichensis, use polarized light cues near the horizon at sunrise and sunset to recalibrate their magnetic compass. birds exposed to a +/-90 deg. shifted artificial polarization pattern at sunrise or sunset recalibrated their magnetic compass, but only when given full ... | 2009 | 19837888 |
| agricultural management affects evolutionary processes in a migratory songbird. | hay harvests have detrimental ecological effects on breeding songbirds, as harvesting results in nest failure. importantly, whether harvesting also affects evolutionary processes is not known. we explored how hay harvest affected social and genetic mating patterns, and thus, the overall opportunity for sexual selection and evolutionary processes for a ground-nesting songbird, the savannah sparrow (passerculus sandwichensis). on an unharvested field, 55% of females were in polygynous associations ... | 2008 | 18302687 |
| polarized light cues underlie compass calibration in migratory songbirds. | migratory songbirds use the geomagnetic field, stars, the sun, and polarized light patterns to determine their migratory direction. to prevent navigational errors, it is necessary to calibrate all of these compass systems to a common reference. we show that migratory savannah sparrows use polarized light cues from the region of sky near the horizon to recalibrate the magnetic compass at both sunrise and sunset. we suggest that skylight polarization patterns are used to derive an absolute (i.e., ... | 2006 | 16902138 |
| little effect of extrapair paternity on the opportunity for sexual selection in savannah sparrows (passerculus sandwichensis). | extrapair paternity (epp) can dramatically increase the opportunity for sexual selection if relatively few males are able to monopolize the majority of fertilizations in a population. although recent work with birds suggests that epp can increase the standardized variance in male reproductive success (is) as much as 13-fold, only a male's within-pair success is typically quantified with any accuracy. in most cases, nearly half of all extrapair young are of unknown parentage. a strong, negative c ... | 2005 | 15807426 |
| social pairing and female mating fidelity predicted by restriction fragment length polymorphism similarity at the major histocompatibility complex in a songbird. | female birds often copulate outside the pair-bond to produce broods of mixed paternity, but despite much recent attention the adaptive significance of this behaviour remains elusive. although several studies support the idea that extra-pair copulations (epcs) allow females to obtain 'good genes' for their offspring, many others have found no relationship between female mating fidelity and traits likely to reflect male quality. a corollary to the good genes hypothesis proposes that females do use ... | 2003 | 14629387 |
| sexual selection and the geography of plasmodium infection in savannah sparrows (passerculus sandwichensis). | according to hamilton and zuk's hypothesis of parasite-mediated sexual selection, host-parasite coevolution maintains variation in male genetic quality and allows for strong intersexual selection in species with high rates of infection. in birds, most interspecific tests of this hypothesis relate the prevalence of blood parasites to some measure of the intensity of sexual selection. such tests often rely on limited sampling of single populations to estimate species-wide infection rates, and many ... | 2001 | 28547489 |
| hippocampal lesions do not impair the geomagnetic orientation of migratory savannah sparrows. | the avian hippocampal formation is known to participate in naturally occurring spatial behavior such as homing in pigeons and cache recovery in food storing passerines, but its participation in the often spectacular migrations of birds remains uncertain. as a first investigation into the possible role of hippocampal formation in migration, the effect of hippocampal formation lesions on the geomagnetic migratory orientation of savannah sparrows was examined. when tested indoors, hippocampal forma ... | 1999 | 10633558 |
| cultural variation in savannah sparrow, passerculus sandwichensis, songs: an analysis using the meme concept. | i used the meme concept to investigate patterns of cultural variation among the songs of eight, geographically distinct populations of savannah sparrows. memes composed of only one syllable were geographically widespread and randomly distributed among populations, but memes of two-, three- and four-syllables became progressively more restricted in their geographical distribution. thus, the populations were memetically more similar with respect to one-syllable memes and more divergent with respec ... | 1998 | 9790711 |
| microgeographic patterns of genetic and morphological variation in savannah sparrows (passerculus sandwichensis). | surveys of genetic population structure are often limited to large geographic scales because geographically close populations are indistinguishable. genetic uniformity across adjacent demes can be interpreted as evidence for cohesion (panmixia) or recent divergence. however, poor genetic resolution at microgeographic scales can also arise from the use of overly conservative (slowly evolving) markers. this study examines the ability of hypervariable, minisatellite loci to discriminate among geogr ... | 1996 | 28565725 |
| dna fingerprinting reveals female preference for male parental care in savannah sparrows. | according to sexual selection theory, females choose mates to ensure access to high quality resources, male parental care, or good genes. this last hypothesis has been hotly debated on both theoretical and empirical grounds. in contrast, female preference for male parental care has received less attention, primarily because the potential benefits of paternal effort seem obvious. the fitness relations are less clear in double-brood species, however, because females can base mating decisions on th ... | 1996 | 8728979 |
| the flexible migratory orientation system of the savannah sparrow (passerculus sandwichensis) | the orientation system of the savannah sparrow (passerculus sandwichensis) is typical of nocturnal migrant passerine birds. it is based on a system of interacting compass senses: magnetic, star, polarized light and, perhaps, sun compasses. the magnetic compass capability develops in birds that have never seen the sky, but the preferred direction of magnetic orientation may be calibrated by celestial rotation (stars at night and polarized skylight patterns during the day). this ability to recalib ... | 1996 | 9317228 |
| sexual dimorphism in passerculus sandwichensis as it is. | | 1989 | 28564156 |
| geographic variation of sexual dimorphism in size of savannah sparrows (passerculus sandwichensis): a test of hypotheses. | the savannah sparrow (passerculus sandwichensis) is a widespread and common north american bird that shows both geographic variation and sexual dimorphism in size. i used information from 24 measurements on 1,791 individuals from 51 populations to test two hypotheses (sexual-selection and niche-partitioning) about the evolution of sexual dimorphism. throughout their range male savannah sparrows are larger, on average, than females. this doubtless reflects darwinian sexual selection, for territor ... | 1987 | 28563795 |
| finite state grammars for dialects of the advertising song of the savannah sparrow (passerculus sandwichensis ). | right-linear finite state grammars were extracted for song sequences of savannah sparrows (passerculus sandwichensis) from ontario and nova scotia. the nova scotia grammar was found to be longer than the ontario grammar (possess more rewrite statements) and allow for the production of sequences containing consecutive trills. these differences are discussed with respect to genetic and environmental factors shaping song behaviour in the two regions. limitations of a nonstochastic finite state gram ... | 1983 | 24923612 |
| sexual recognition and anticuckoldry behaviour in savannah sparrows. | | 1980 | 7427824 |
| heritability and evolvability of morphological traits of savannah sparrows (passerculus sandwichensis) breeding in agricultural grasslands. | heritability and evolvability estimates of adult traits from free-living bird populations can be used to gauge the ability of populations to respond to selection, but are rare due to difficulties in gathering detailed pedigree information. the capacity to respond to selection is particularly important for species occupying managed habitats such as agricultural grasslands because of the potential for humans to accidentally influence traits. we calculated heritability and evolvability of six morph ... | 2019 | 30640933 |
| wild birds learn songs from experimental vocal tutors. | in eight groups of animals, including humans and songbirds, juveniles are understood to learn vocalizations by listening to adults [1-4]. experimental studies of laboratory-reared animals support this hypothesis for vocal learning [5-7], yet we lack experimental evidence of vocal learning in wild animals. we developed an innovative playback technology involving automated loudspeakers that broadcast songs with distinctive acoustic signatures. we used this technology to simulate vocal tutors in th ... | 2018 | 30293720 |
| noisy anthropogenic infrastructure interferes with alarm responses in savannah sparrows (passerculus sandwichensis). | many birds rely on anti-predator communication to protect their nests; however, anthropogenic noise from industrial activities such as oil and gas development may disrupt acoustic communication. here, we conducted acoustic playback experiments to determine whether savannah sparrows (passerculus sandwichensis) responded to conspecific alarm calls by delaying feeding visits, and whether this response was impaired by noise-producing natural gas compressor stations, generator- or grid-powered screw ... | 2018 | 29892404 |
| population history and the selective landscape shape patterns of osmoregulatory trait divergence in tidal marsh savannah sparrows (passerculus sandwichensis). | a persistent challenge in making associations between phenotypic and environmental variation is understanding how ecological factors and demographic history interact to shape adaptive outcomes. evaluating the degree to which conspecific populations exposed to similar environmental pressures respond in parallel provides a powerful framework for addressing this challenge. we took this comparative approach with multiple populations of savannah sparrows (passerculus sandwichensis) found in tidal mar ... | 2020 | 31750547 |
| seasonal and diurnal variation of singing activity: their possible relationship with intra- and inter-sexual function in the savannah sparrow, passerculus sandwichensis. | we studied seasonal and diurnal variation of singing activity in a single-song repertoire species, the savannah sparrow (passerculus sandwichensis), to explore the possible functions of the song. we observed a total of 47 territorial males (11 over three years, 28 over two years) on a daily basis. for all paired and unpaired males, and across all stages of the breeding season, we recorded total number of songs produced (singing persistence), the number of instances of aggression per 10-minute pe ... | 2019 | 31251485 |
| divergent mitochondrial lineages arose within a large, panmictic population of the savannah sparrow (passerculus sandwichensis). | unusual patterns of mtdna diversity can reveal interesting aspects of a species' biology. however, making such inferences requires discerning among the many alternative scenarios that could underlie any given mtdna pattern. next-generation sequencing methods provide large, multilocus data sets with increased power to resolve unusual mtdna patterns. a mtdna-based phylogeography of the savannah sparrow (passerculus sandwichensis) previously identified two sympatric, but divergent (~2%) clades with ... | 2019 | 30770598 |
| sea-level rise, habitat loss, and potential extirpation of a salt marsh specialist bird in urbanized landscapes. | sea-level rise (slr) impacts on intertidal habitat depend on coastal topology, accretion, and constraints from surrounding development. such habitat changes might affect species like belding's savannah sparrows (passerculus sandwichensis beldingi; bssp), which live in high-elevation salt marsh in the southern california bight. to predict how bssp habitat might change under various slr scenarios, we first constructed a suitability model by matching bird observations with elevation. we then mapped ... | 2018 | 30250688 |
| noise source and individual physiology mediate effectiveness of bird songs adjusted to anthropogenic noise. | anthropogenic noise is a pervasive pollutant altering behaviour of wildlife that communicates acoustically. some species adjust vocalisations to compensate for noise. however, we know little about whether signal adjustments improve communication in noise, the extent to which effectiveness of adjustments varies with noise source, or how individual variation in physiology varies with response capacity. we played noise-adjusted and unadjusted songs to wild passerculus sandwichensis (savannah sparro ... | 2018 | 29500452 |
| design and calibration of a novel bio-inspired pixelated polarized light compass. | animals, such as savannah sparrows and north american monarch butterflies, are able to obtain compass information from skylight polarization patterns to help them navigate effectively and robustly. inspired by excellent navigation ability of animals, this paper proposes a novel image-based polarized light compass, which has the advantages of having a small size and being light weight. firstly, the polarized light compass, which is composed of a charge coupled device (ccd) camera, a pixelated pol ... | 2017 | 29135927 |
| divorce in an island bird population: causes, consequences, and lack of inheritance. | divorce (mate switching) is widely considered an adaptive strategy that female birds use to improve their reproductive success. however, in few species are the causes and consequences of divorce well understood, and the genetic basis and inheritance of divorce have never been explored. in savannah sparrows (passerculus sandwichensis) breeding on kent island, new brunswick, canada, 47.0% of pairs in which both partners survived to the following breeding season ended in divorce. secondary females, ... | 2017 | 28937818 |