Publications

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ticks (acari: ixodidae) infesting wild birds (aves) and white-footed mice in lyme, ct.birds were captured and recaptured (20.8% of 5,297) with japanese mist nets, and white-footed mice, peromyscus leucopus (rafinesque), were caught and recaught (69.1% of 355) with sherman box traps during the late spring, summer, and early fall from july 1989 through october 1991 to study tick-host relationships in lyme, ct. ixodes scapularis say, a vector of lyme disease spirochetes, borrelia burgdorferi sensu stricto johnson, schmid, hye, steigerwalt & brenner, infested 803 birds (15.2%) in 36 ...19957650706
Widespread dispersal of Borrelia burgdorferi-infected ticks collected from songbirds across Canada.Abstract Millions of Lyme disease vector ticks are dispersed annually by songbirds across Canada, but often overlooked as the source of infection. For clarity on vector distribution, we sampled 481 ticks (12 species and 3 undetermined ticks) from 211 songbirds (42 species/subspecies) nationwide. Using PCR, 52 (29.5%) of 176 Ixodes ticks tested were positive for the Lyme disease spirochete, Borrelia burgdorferi s.l. Immature blacklegged ticks, Ixodes scapularis, collected from infested songbird ...201121864130
site specific pcb-correlated interspecies differences in organ somatic indices.we correlated site specific differences in the organ somatic indices of nestlings of five passerine species (tree swallow, red-winged blackbird, house wren, carolina chickadee, and eastern bluebird) with the degree of polychlorinated biphenyls (pcb) exposure in ovo and post-hatching. the birds were exposed to pcbs at or downstream of four pcb-contaminated sites. of the organs evaluated for this paper, brain, bursa, heart, kidneys, lungs, pancreas, spleen, stomach, and thyroid varied significantl ...200616317482
external heart deformities in passerine birds exposed to environmental mixtures of polychlorinated biphenyls during development.necropsy-observable cardiac deformities were evaluated from 283 nestling passerines collected from one reference site and five polychlorinated biphenyl (pcb)-contaminated sites around bloomington and bedford, indiana, usa. hearts were weighed and assessed on relative scales in three dimensions (height, length, and width) and for externally visible deformities. heart weights normalized to body weight (heart somatic index) were decreased significantly at the more contaminated sites in both house w ...200616519318
estimating the effects of habitat and biological interactions in an avian community.we used repeated sightings of individual birds encountered in community-level surveys to investigate the relative roles of habitat and biological interactions in determining the distribution and abundance of each species. to analyze these data, we developed a multispecies n-mixture model that allowed estimation of both positive and negative correlations between abundances of different species while also estimating the effects of habitat and the effects of errors in detection of each species. usi ...201526287671
rickettsial infection in ticks infesting wild birds from two eco-regions of argentina.several tick-borne rickettsia species are recognized human pathogens in argentina. here we evaluated rickettsial infection in ticks collected on passerine birds during 2011-2012 in two eco-regions of argentina. the ticks were processed by molecular analysis through polymerase chain reaction (pcr) detection and dna sequencing of fragments of two rickettsial genes, glta and ompa. a total of 594 tick specimens (532 larvae and 62 nymphs), representing at least 4 species (amblyomma tigrinum, ixodes p ...201627580393
multiple lines of evidence risk assessment of terrestrial passerines exposed to pcdfs and pcdds in the tittabawassee river floodplain, midland, michigan, usa.a site-specific multiple lines of evidence risk assessment was conducted for house wrens (troglodytes aedon) and eastern bluebirds (sialia sialis) along the tittabawassee river downstream of midland, michigan, where concentrations of polychlorinated dibenzofurans (pcdfs) and polychlorinated dibenzo-p-dioxins (pcdds) in flood-plain soils and sediments are greater compared to upstream areas and some of the greatest anywhere in the world. lines of evidence supporting the population-level assessment ...201121804755
immune-challenged house wren broods differ in the relative strengths of their responses among different axes of the immune system.single components of the immune system are widely used to assess immune function in free-living vertebrates. however, as different immunological components are triggered by different types of threats and may be regulated independently, there is little reason to assume that they should respond similarly if challenged. we investigated whether three commonly assayed immune responses, cutaneous immune activity (phytohaemagglutinin assay), antibody response (tetanus toxoid immunization), and plasma b ...200818298497
reproductive success of three passerine species exposed to dioxin-like compounds near midland, michigan, usa.nests of three passerine birds, house wren (howr), tree swallow (tres), and eastern bluebird (eabl) were monitored daily (2005-2007) at study areas (sas) downstream of midland, michigan where soil and sediment concentrations of polychlorinated dibenzofurans (pcdfs) were significantly greater than the regional background concentrations and upstream reference areas (ras). similarly, tres research conducted at sites contaminated with dioxin-like compounds indicated that concentrations of polychlori ...201222392542
maternal natal environment and breeding territory predict the condition and sex ratio of offspring.females in a variety of taxa adjust offspring sex ratios to prevailing ecological conditions. however, little is known about whether conditions experienced during a female's early ontogeny influence the sex ratio of her offspring. we tested for past and present ecological predictors of offspring sex ratios among known-age females that were produced as offspring and bred as adults in a population of house wrens. the body condition of offspring that a female produced and the proportion of her offs ...201728286350
dietary exposure of three passerine species to pcdd/dfs from the chippewa, tittabawassee, and saginaw river floodplains, midland, michigan, usa.dietary exposure of house wrens (troglodytes aedon), tree swallows (tachycineta bicolor), and eastern bluebirds (sialia sialis) to polychlorinated dibenzofurans (pcdfs) and polychlorinated dibenzo-p-dioxins (pcdds) near midland, michigan (usa) was evaluated based on site-specific data, including concentrations of residues in bolus samples and individual invertebrate orders and dietary compositions by study species. site-specific dietary compositions for the three species were similar to those re ...201120145996
pre- and postnatal effects of corticosterone on fitness-related traits and the timing of endogenous corticosterone production in a songbird.maternally derived corticosterone in the egg and corticosterone produced endogenously by altricial nestling birds play essential roles during development. although persistently high corticosterone levels can be harmful, moderately elevated levels above baseline can lead to reallocation of resources between growth and maintenance to ensure immediate survival or to enhance the development of fitness-related traits. we tested two hypotheses concerning the fitness consequences of elevated corticoste ...201627279255
passerine exposure to primarily pcdfs and pcdds in the river floodplains near midland, michigan, usa.house wren (troglodytes aedon), tree swallow (tachycineta bicolor), and eastern bluebird (sialia sialis) tissues collected in study areas (sas) downstream of midland, michigan (usa) contained concentrations of polychlorinated dibenzofurans (pcdfs) and polychlorinated dibenzo-p-dioxins (pcdds) greater than in upstream reference areas (ras) in the region. the sum of concentrations of pcdd/dfs (sigmapcdd/dfs) in eggs of house wrens and eastern bluebirds from sas were 4- to 22-fold greater compared ...201019894014
no effect of blood sampling or phytohaemagglutinin injection on postfledging survival in a wild songbird.the injection of phytohaemagglutinin (pha) and sampling of blood are widely used in studies of wild vertebrates to assess components of immune and endocrine function and health state and to obtain genetic material. despite the pervasive use of these techniques in the life sciences, their potential effects on survival are rarely considered. for example, whether injection of the immunogen pha into body parts critical for locomotion (e.g., the prepatagium, or wing web, in birds) affects survival ha ...201627092240
new data on philornis seguyi garcia (1952) (diptera, muscidae).philornis meinert is a very interesting muscidae (diptera) genus whose larvae are associated with a wide range of bird species. the existing description of philornis seguyi garcia (1952), which was reported in argentina, so far involves only the female. during the 2000-2002 breeding seasons, we collected philornis flies from six bird species in buenos aires province, argentina. all the flies were identified as p. seguyi. based on this material, we describe the larva, puparium, adult male, and ma ...200516532187
within-female plasticity in sex allocation is associated with a behavioural polyphenism in house wrens.sex allocation theory assumes individual plasticity in maternal strategies, but few studies have investigated within-individual changes across environments. in house wrens, differences between nests in the degree of hatching synchrony of eggs represent a behavioural polyphenism in females, and its expression varies with seasonal changes in the environment. between-nest differences in hatching asynchrony also create different environments for offspring, and sons are more strongly affected than da ...201626687708
mutation-biased adaptation in andean house wrens. 201526489650
accumulation of polychlorinated biphenyls from floodplain soils by passerine birds.eggs, nestlings, and adults of the eastern bluebird (sialia sialis) and house wren (troglodytes aedon) were collected at a polychlorinated biphenyl (pcb)-contaminated site and a reference location on the kalamazoo river (mi, usa). eggs and nestlings of eastern bluebirds at the more contaminated location contained concentrations of 8.3 and 1.3 mg/kg, respectively, of total pcbs and 77 and 6.3 ng/kg, respectively, of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (teqs). eggs, nestlings, and adul ...200616764468
increased extra-pair paternity in broods of aging males and enhanced recruitment of extra-pair young in a migratory bird.despite keen interest in extra-pair mating in birds, its adaptive significance remains unresolved. here, we use a multi-year dataset to test whether traits of a female's social mate influence her propensity to produce extra-pair offspring in a population of house wrens, and whether producing extra-pair young has consequences for a female's fitness through effects on offspring survival. females were most likely to produce extra-pair offspring when paired with old males and when paired with males ...201526258950
reproductive success of passerines exposed to polychlorinated biphenyls through the terrestrial food web of the kalamazoo river.the eastern bluebird (sialia sialis) and the house wren (troglodytes aedon) were identified as ecological receptors of concern due to exposure and potential effects stemming from polychlorinated biphenyl (pcb) contamination in floodplain soils of the kalamazoo river superfund site, michigan, usa. measures of population health were compared at a contaminated and a less-contaminated reference location. during this 3-year study, productivity of bluebirds was significantly less at the downstream loc ...200716343620
constitutive innate immunity is a component of the pace-of-life syndrome in tropical birds.we studied the relationship between one component of immune function and basal metabolic rate (bmr), an indicator of the 'pace-of-life syndrome', among 12 tropical bird species and among individuals of the tropical house wren (troglodytes aedon), to gain insights into functional connections between life history and physiology. to assess constitutive innate immunity we introduced a new technique in the field of ecological and evolutionary immunology that quantifies the bactericidal activity of wh ...200516087427
serologic evidence of west nile virus infection in birds, tamaulipas state, méxico.following the introduction of west nile virus (wnv) into north america in 1999, surveillance for wnv in migratory and resident birds was established in tamaulipas state, northern méxico in december 2001. overall, 796 birds representing 70 species and 10 orders were captured and assayed for antibodies to wnv. nine birds had flavivirus-specific antibodies by epitope-blocking enzyme-linked immunosorbent assay; four were confirmed to have antibody to wnv by plaque reduction neutralization test. the ...200314733673
neonatal body condition, immune responsiveness, and hematocrit predict longevity in a wild bird population.measures of body condition, immune function, and hematological health are widely used in ecological studies of vertebrate populations, predicated on the assumption that these traits are linked to fitness. however, compelling evidence that these traits actually predict long-term survival and reproductive success among individuals in the wild is lacking. here, we show that body condition (i.e., size-adjusted body mass) and cutaneous immune responsiveness to phytohaemagglutinin (pha) injection amon ...201425505800
age-dependent changes in plasma and brain cholinesterase activities of house wrens and european starlings.we determined age-dependent changes in plasma and brain cholinesterase (che) activity for two species of passerines: house wren (troglodytes aedon) and european starling (sturnus vulgaris, starling). in plasma from nestlings of both species, total che activity increased with age, acetycholinesterase (ache, ec 3.1.1.7) activity declined rapidly immediately after hatching, and butyrylcholinesterase (bche, ec 3.1.1.8) activity increased steadily. for both species, total che and bche activities and ...200314567225
radiographic monitoring of the ossification of long bones in kori (ardeotis kori) and white-bellied (eupodotis senegalensis) bustards.a serial radiographic study was conducted on eight kori bustard (ardeotis kori) and four white-bellied bustard (eupodotis senegalensis) chicks to determine the pattern of long bone development and to establish radiographic standards for assessing skeletal maturity. the ossification pattern, appearance of secondary ossification centres, and epiphyseal fusion of the long bones in kori and white-bellied bustards were similar to those in houbara bustards (chlamydotis undulata macqueenii), rufous-cre ...19989839896
molecular tracking of individual host use in the shiny cowbird - a generalist brood parasite.generalist parasites exploit multiple host species at the population level, but the individual parasite's strategy may be either itself a generalist or a specialist pattern of host species use. here, we studied the relationship between host availability and host use in the individual parasitism patterns of the shiny cowbird molothrus bonariensis, a generalist avian obligate brood parasite that parasitizes an extreme range of hosts. using five microsatellite markers and an 1120-bp fragment of the ...201627547305
the structure of an avian syllable syntax network.a common result in recent linguistic studies on word association networks is that their topology can often be described by zipf's law, in which most words have few associations, whereas a few words are highly connected. however, little is known about syntactic networks in more rudimentary communication systems, which could represent a window into the early stages of language evolution. in this study, we investigate the syntactic network formed by syllable associations in the song of the oscine b ...201424792818
differential accumulation of polychlorinated biphenyl congeners in the terrestrial food web of the kalamazoo river superfund site, michigan.a series of field studies was conducted to determine the bioaccumulation of polychlorinated biphenyl (pcb) congeners in the terrestrial food web of the kalamazoo river flood plain. samples included colocated soils, native plants likely to be consumed by wildlife, several taxa of terrestrial invertebrates, small mammals, passerine bird eggs, nestlings, and adults, and great horned owl plasma and eggs. mean concentrations of total pcbs in samples from the former trowbridge impoundment were 6.5 mg/ ...200516173551
eleven microsatellite loci isolated from the banded wren (thryothorus pleurostictus).we describe 11 microsatellite loci isolated from the banded wren (thryothorus pleurostictus), a neotropical species for which understanding the genetic mating system is important for testing questions about the species' unusual vocal behavior. screening of these loci revealed extremely low allelic variation in a costa rican population. allelic variation at these and other previously developed loci is substantially higher in two other wren species, the southern house wren (troglodytes aedon bonar ...200718392115
behavioral plasticity in response to perceived predation risk in breeding house wrens.predation is a significant cause of nest failure in passerine birds, and, thus, natural selection is expected to favor behavioral plasticity to allow birds to respond to perceived changes in predation risk. however, behavioral plasticity in response to perceived predation risk, and its potential fitness-related costs, are understudied. in a wild population of breeding house wrens (troglodytes aedon), we tested the hypotheses that (1) birds show behavioral plasticity in response to perceived nest ...201728736461
no effect of carotenoid supplementation on phytohemagglutinin response or body condition of nestling house wrens.carotenoids are an essential and often limiting resource in animals and play important roles in immune system function. in birds, the period shortly after hatching is an energetically demanding stage characterized by rapid growth in body size and organ systems, including the immune system. availability of carotenoids for the growing nestlings may be of particular importance and potentially limiting at this stage of development. we tested the hypothesis that the availability of carotenoids for th ...201322237286
new species of parasitic quill mites of the genus picobia (acari: syringophilidae: picobiinae) from north american birds.five new species of the genus picobia are described and illustrated: (1) p. leucophaeus sp. nov. from the laughing gull leucophaeus atricilla l. (charadriiformes: laridae) from texas; (2) p. troglodytes sp. nov. from the house wren troglodytes aedon vieillot (passeriformes: troglodytidae) from california; (3) p. cardinalis sp. nov. from the northern cardinal cardinalis cardinalis (l.) (passeriformes: cardinalidae) from texas; (4) p. carpodacus sp. nov. from the purple finch carpodacus purpureus ...201020939365
adaptive sex allocation in relation to hatching synchrony and offspring quality in house wrens.increased variance in the reproductive success of males relative to females favors mothers that optimally allocate sons and daughters to maximize their fitness return. in altricial songbirds, one influence on the fitness prospects of offspring arises through the order in which nestlings hatch from their eggs, which affects individual mass and size before nest leaving. in house wrens (troglodytes aedon), the influence of hatching order depends on the degree of hatching synchrony, with greater var ...201121508608
partial host fidelity in nest selection by the shiny cowbird (molothrus bonariensis), a highly generalist avian brood parasite.obligate avian brood parasites can be host specialists or host generalists. in turn, individual females within generalist brood parasites may themselves be host specialists or generalists. the shiny cowbird molothrus bonariensis is an extreme generalist, but little is known about individual female host fidelity. we examined variation in mitochondrial control region sequences from cowbird chicks found in nests of four common argentinean hosts. haplotype frequency distributions differed among cowb ...200717714308
cutaneous immune activity, but not innate immune responsiveness, covaries with mass and environment in nestling house wrens (troglodytes aedon).immunological measures are increasingly being applied to ecological and evolutionary studies of wild vertebrates, yet frequently it is not clear how condition and environmental factors correlate with various immune parameters. we used mixed-model anova to examine the effects of several measures of condition (both morphological and physiological) and environmental factors on two measures of immune responsiveness in nestling house wrens (troglodytes aedon l.) to test the hypothesis that nestlings ...201020230303
extra-pair young in house wren broods are more likely to be male than female.sex-allocation theory predicts that females should preferentially produce offspring of the sex with greater fitness potential. in socially monogamous animal species, extra-pair mating often increases the variance in fitness of sons relative to daughters. thus, in situations where offspring sired by a female's extra-pair mate(s) will typically have greater fitness potential than offspring sired by the within-pair mate, sex-allocation theory predicts that females will bias the sex of offspring sir ...200919324727
do shiny cowbird females adjust egg pecking behavior according to the level of competition their chicks face in host nests?interspecific brood parasites, like the shiny cowbird (molothrus bonariensis), lay eggs in nests of other species. shiny cowbird females peck and puncture eggs when they parasitize host nests. this behavior increases the survival of cowbird chicks when they have to compete for food with larger nestmates. however, cowbird chicks may benefit from smaller nestmates as they increase food provisioning by parents and the cowbird chicks secure most extra provisioning. we investigated whether egg-peckin ...201222119844
female house wrens (troglodytes aedon) increase the size, but not immunocompetence, of their offspring through extra-pair mating.house wrens are typically socially monogamous, but frequently engage in extra-pair matings leading to multisired broods. because females do not appear to acquire direct material benefits from their extra-pair mates, we tested the hypothesis that female house wrens derive indirect genetic benefits, such as enhanced immunocompetence (cutaneous immune activity, humoral immunity, and plasma bactericidal activity) and condition (size and haematoserological traits) for their offspring, by mating polya ...200818662223
why are incubation periods longer in the tropics? a common-garden experiment with house wrens reveals it is all in the egg.incubation periods of neotropical birds are often longer than those of related species at temperate latitudes. we conducted a common-garden experiment to test the hypothesis that longer tropical incubation periods result from longer embryo development times rather than from different patterns of parental incubation behavior. house wrens, one of few species whose geographic range includes tropical equatorial and temperate high latitudes, have incubation periods averaging 1.2 days longer at tropic ...200818254684
differential reproductive success favours strong host preference in a highly specialized brood parasite.obligate avian brood parasites show dramatic variation in the degree to which they are host specialists or host generalists. the screaming cowbird molothrus rufoaxillaris is one of the most specialized brood parasites, using a single host, the bay-winged cowbird (agelaioides badius) over most of its range. coevolutionary theory predicts increasing host specificity the longer the parasite interacts with a particular avian community, as hosts evolve defences that the parasite cannot counteract. ac ...200818647716
genotype and extra-pair paternity in the house wren: a rare-male effect?females in socially monogamous species may select extra-pair (ep) mates to increase the heterozygosity, and hence fitness, of their offspring. we tested this hypothesis in the house wren (troglodytes aedon), a largely monogamous songbird in which ep young are common. we typed paired males and females, nestlings, and males on neighbouring territories, at five to seven microsatellite loci over 2 years in a wyoming, usa, population. we identified ep sires at 20 nests with ep young. in pairwise comp ...200312965031
arsenic concentrations in house wrens from whitewood creek, south dakota, usa. 200212069056
size of nest-cavity entrance influences male attractiveness and paternal provisioning in house wrens.in altricial birds, parental provisioning is plastic and can respond to a variety of environmental stimuli. in this study, we manipulated the size of entrances into artificial nest cavities (i.e., nestboxes) in a population of house wrens (troglodytes aedon) as a means of manipulating a male's sexual attractiveness, and examined changes in parental provisioning. nest cavities with large entrances are less desirable as nesting sites, and the males at these sites are less attractive to females. th ...201728579698
relatively simple, precise methods to analyze temperature transients in ectotherms.relatively complex core-shell models have been used to precisely characterize times and temperatures for ectotherms. there is a simpler method using a second-order analysis of heat flux. we derive the method from an equivalent mechanical system, correct some previously published inaccuracies, and show how to use the method by analyzing thermal transients for house wren eggs under natural conditions.200111163928
sex ratio manipulation within broods of house wrens, troglodytes aedon.trivers & willard (1973, science, 179, 90-92) developed an economic theory of parental investment to explain how the relative profitability of sons and daughters varies under specific ecological conditions. in their maternal condition hypothesis they proposed that in polygynous species, the sex of an offspring should be associated with the amount of parental care likely to be made available to it. in these species, the amount of parental investment directed towards offspring may differentially i ...200010877902
reanalysis gives further support to the 'shotgun' model of shiny cowbird parasitism of house wren nests. 19989933555
spring temperatures influence selection on breeding date and the potential for phenological mismatch in a migratory bird.climate change has affected the seasonal phenology of a variety of taxa, including that of migratory birds and their critical food resources. however, whether climate-induced changes in breeding phenology affect individual fitness, and how these changes might therefore influence selection on breeding date remain unresolved. here, we use a 36-yr dataset from a long-term, individual-based study of house wrens (troglodytes aedon) to test whether the timing of avian breeding seasons is associated wi ...201627859132
social mating system affects the frequency of extra-pair paternity in house wrenswe tested two hypotheses regarding the effect of the social mating system on extra-pair paternity in an illinois population of house wrens, troglodytes aedonaccording to the genetic-quality hypothesis, polygynous males are of higher quality than monogamists, and monogamously paired females, in an attempt to obtain high-quality genes, should have a greater proportion of extra-pair nestlings in their nests than polygynously paired females. according to the trade-off hypothesis, polygynists, with t ...19979398365
elevated corticosterone during egg production elicits increased maternal investment and promotes nestling growth in a wild songbird.glucocorticoids circulating in breeding birds during egg production accumulate within eggs, and may provide a potent form of maternal effect on offspring phenotype. however, whether these steroids affect offspring development remains unclear. here, we employed a non-invasive technique that experimentally elevated the maternal transfer of corticosterone to eggs in a wild population of house wrens. feeding corticosterone-injected mealworms to free-living females prior to and during egg production ...201627189763
temperatures of house-wrens. 192917784448
transcontinental latitudinal variation in song performance and complexity in house wrens (troglodytes aedon).there is growing interest in latitudinal effects on animal behaviour and life history. one recent focus is on birdsong, which is hypothesized to be more elaborated or complex in the north temperate zone compared with the tropics. current evidence is mixed and based on cross-species comparisons, or single species with restricted distributions. we circumvent these limitations using a transcontinental sample of 358 songs from house wrens (troglodytes aedon) at 281 locations spanning more than 100° ...201626865297
chemical defense in the plant bug lopidea robiniae (uhler).secretions from the metathoracic glands (mtg) of the black locust bug, lopidea robiniae (uhler) (heteroptera: miridae) contained six major compounds, including (e)-2-hexenal, (e)-2-hexen-1-ol, (e)-2-octenal, (e)-2-octen-1-ol (e)-2-heptenal, and (z)-3-octen-1-ol. males and females did not differ significantly in the relative compositions of identified compounds. in feeding trials, six bird species [robin (turdus migratorious), blue jay (cyanocitta cristata), brown thrasher (toxostoma rufum), kill ...200211944836
metal accumulation and performance of nestlings of passerine bird species at an urban brownfield site.the use of passerine species as bioindicators of metal bioaccumulation is often underutilized when examining the wildlife habitat value of polluted sites. in this study we tested feathers of nestlings of two common bird species (house wren and american robin) for accumulation of pb, zn, as, cr, cu, fe in comparison of a polluted, urban brownfield with a rural, unpolluted site. house wren nestlings at the study site accumulated significantly greater concentrations of all target metals except zn. ...201020185215
eggshell porosity covaries with egg size among female house wrens (troglodytes aedon) but is unrelated to incubation onset and egg-laying order within clutches.in birds, the duration of egg incubation (the time from incubation onset to hatching) can affect multiple components of nest success, but what affects incubation duration? previous studies suggest that incubation duration is affected by both parental behavior and components of the egg, which have yet to be determined. one egg component that may be related to incubation behavior and the time until hatching is eggshell porosity, which affects the exchange of metabolic gasses and water vapor across ...201526146408
cascading costs of reproduction in female house wrens induced to lay larger clutches.in many species, females produce fewer offspring than they are capable of rearing, possibly because increases in current reproductive effort come at the expense of a female's own survival and future reproduction. to test this, we induced female house wrens (troglodytes aedon) to lay more eggs than they normally would and assessed the potential costs of increasing cumulative investment in the three main components of the avian breeding cycle - egg laying, incubation and nestling provisioning. fem ...201526012556
immune activation generates corticosterone-mediated terminal reproductive investment in a wild bird.despite classical expectations of a trade-off between immune activity and reproduction, an emergent view suggests that individuals experiencing activation of their immune system actually increase reproductive effort and allocation to offspring as a form of terminal investment in response to reduced survival probability. however, the components and mechanisms of increased parental investment following immunostimulation are currently unknown. we hypothesize that increased glucocorticoid production ...201525996862
genetic and environmental variation in condition, cutaneous immunity, and haematocrit in house wrens.life-history studies of wild bird populations often focus on the relationship between an individual's condition and its capacity to mount an immune response, as measured by a commonly-employed assay of cutaneous immunity, the pha skin test. in addition, haematocrit, the packed cell volume in relation to total blood volume, is often measured as an indicator of physiological performance. a multi-year study of a wild population of house wrens has recently revealed that those exhibiting the highest ...201425471117
persistent sex-by-environment effects on offspring fitness and sex-ratio adjustment in a wild bird population.a major component of sex-allocation theory, the trivers-willard model (twm), posits that sons and daughters are differentially affected by variation in the rearing environment. in many species, the amount of parental care received is expected to have differing effects on the fitness of males and females. when this occurs, the twm predicts that selection should favour adjustment of the offspring sex ratio in relation to the expected fitness return from offspring. however, evidence for sex-by-envi ...201525266087
food supplementation fails to reveal a trade-off between incubation and self-maintenance in female house wrens.incubating birds must allocate their time and energy between maintaining egg temperature and obtaining enough food to meet their own metabolic demands. we tested the hypothesis that female house wrens (troglodytes aedon) face a trade-off between incubation and self-maintenance by providing females with supplemental food during incubation. we predicted that food supplementation would increase the amount of time females devoted to incubating their eggs, lower their baseline plasma corticosterone l ...201425184281
nestling passerines are not important hosts for amplification of west nile virus in chicago, illinois.nestling birds have been hypothesized to be important hosts for mosquito-borne arboviruses, but the role of nestlings for west nile virus (wnv) amplification remains unclear. we sampled open-cup and cavity-nesting passerines in chicago, illinois, an area of intense wnv transmission, to determine infection rates in nestlings and mosquitoes, and to test whether mosquitoes are attracted to nesting birds. analysis of culex pipiens mosquito populations demonstrated wnv amplification to high mosquito ...200818759639
relative importance of bird species as hosts for immature ixodes dammini (acari: ixodidae) in a suburban residential landscape of southern new york state.abundance of birds and their tick parasites were estimated in a residential community located in westchester county, ny, where lyme disease is endemic. in total, 36 bird species (416 captures) were collected, of which 25 species (69%) were parasitized by ticks. ixodes dammini spielman, clifford, piesman & corwin composed 96.4% of the 1,067 ticks found on birds. the bird species most heavily parasitized was house wren, troglodytes aedon vieillot (11.1 ixodes dammini per bird). relative density es ...19938360897
sibling cooperation influences the age of nest leaving in an altricial bird.in altricial birds, siblings raised within a nest usually leave the nest within hours of each other, despite often differing considerably in age. the youngest members of the brood are typically underdeveloped at this time and less likely than their older siblings to survive outside the nest, yet they risk abandonment if they do not fledge with their older siblings. nest leaving is usually initiated by the older offspring, which may delay this process to provide more time for their younger siblin ...201323669540
physically challenging song traits, male quality, and reproductive success in house wrens.physically challenging signals are likely to honestly indicate signaler quality. in trilled bird song two physically challenging parameters are vocal deviation (the speed of sound frequency modulation) and trill consistency (how precisely syllables are repeated). as predicted, in several species, they correlate with male quality, are preferred by females, and/or function in male-male signaling. species may experience different selective pressures on their songs, however; for instance, there may ...201323527137
maternal transfer of mercury to songbird eggs.we evaluated the maternal transfer of mercury to eggs in songbirds, determined whether this relationship differed between songbird species, and developed equations for predicting mercury concentrations in eggs from maternal blood. we sampled blood and feathers from 44 house wren (troglodytes aedon) and 34 tree swallow (tachycineta bicolor) mothers and collected their full clutches (n = 476 eggs) within 3 days of clutch completion. additionally, we sampled blood and feathers from 53 tree swallow ...201728688298
time of feeding and possible associated thermoregulatory benefits in bronze mannikins lonchura cucullata.birds with a small body size have a high surface area to volume ratio, and this means that they have a high rate of heat loss to the environment. birds may employ behavioural strategies in order to counter this heat loss. the adjustment of feeding patterns in the short term is probably the least documented of all of these strategies. feeding results in the specific dynamic effect (sde) which increases the metabolic rate of animals after a feeding bout. this increase in metabolic rate has been re ...200111691616
polycyclic aromatic hydrocarbons, aliphatic hydrocarbons, trace elements, and monooxygenase activity in birds nesting on the north platte river, casper, wyoming, usa.tree swallow (tachycineta bicolor) and house wren (troglodytes aedon) eggs and chicks were collected near a refinery site on the north platte river, casper. wyoming, usa and at a reference site 10 km upstream. total polycyclic aromatic hydrocarbon (pah) concentrations in swallow and wren chicks were higher at the refinery site than at the reference site. polycyclic aromatic hydrocarbon concentrations in sediment and chick dietary samples were consistent with these findings. the general lack of m ...200111349865
wild birds as host of borrelia burgdorferi sensu lato in northwestern argentina.borrelia burgdorferi sensu lato (s. l.) spirochetes are associated with a wide range of vectors and hosts. birds are important hosts in the ecology of some hard ticks (ixodidae) in northwestern argentina, where b. burgdorferi s.l. have been detected in ixodes pararicinus. we evaluated borrelia infection in ticks collected from wild birds by molecular analysis through the presence of borrelia dna (by nested-pcr targeting the fla gene). a total of 381 ticks (357 larvae and 24 nymphs) belonging to ...201830104124
sex-biased terminal investment in offspring induced by maternal immune challenge in the house wren (troglodytes aedon).the reproductive costs associated with the upregulation of immunity have been well-documented and constitute a fundamental trade-off between reproduction and self-maintenance. however, recent experimental work suggests that parents may increase their reproductive effort following immunostimulation as a form of terminal parental investment as prospects for future reproduction decline. we tested the trade-off and terminal investment hypotheses in a wild population of house wrens (troglodytes aedon ...201222456887
interactive effects of parental age on offspring fitness and age-assortative mating in a wild bird.variation in parental age can have important consequences for offspring fitness and the structure of populations and disease transmission. however, our understanding of the effects of parental age on offspring in natural populations is limited. here, we investigate consequences of parental age for offspring fitness and test for age-assortative mating in a short-lived bird, the house wren (troglodytes aedon). offspring immunoresponsiveness increased with maternal age and decreased with paternal a ...201729218330
experimentally increased in ovo testosterone leads to increased plasma bactericidal activity and decreased cutaneous immune response in nestling house wrens.maternally derived testosterone in the eggs of birds may benefit nestlings by increasing various aspects of their growth, condition and behavioral development, but these benefits may come at a cost, including suppression of immune responsiveness. experiments on a variety of species in which in ovo levels of testosterone have been experimentally increased have produced mixed results; some have found increased growth and suppressed immune function of nestlings whereas others have found the opposit ...201121795576
evidence for heterozygote instability in microsatellite loci in house wrens.microsatellite loci have high mutation rates and high levels of allelic variation, but the factors influencing their mutation rate are not well understood. the proposal that heterozygosity may increase mutation rates has profound implications for understanding the evolution of microsatellite loci, but currently has limited empirical support. we examined 20 microsatellite mutations identified in an analysis of 12 260 meiotic events across three loci in two populations of a songbird, the house wre ...201120702452
the effects of conspecific attraction and habitat quality on habitat selection in territorial birds (troglodytes aedon). 199718811306
surplus nest boxes and the potential for polygyny affect clutch size and offspring sex ratio in house wrens.females of many species can gain benefits from being choosy about their mates and even exhibit context-dependent investment in reproduction in response to the quality of their breeding situation. here, we show that if a male house wren is provided with surplus nest boxes in his territory, his mate lays a larger clutch with a significantly higher proportion of sons. this response to a territory characteristic directly associated with male competitive ability, and ultimately to male reproductive s ...200616790407
manipulation of offspring sex ratio by second-mated female house wrens.in 1973, trivers and willard proposed that offspring sex ratio should be associated with the quality of parental care likely to be provided to the offspring. we tested this hypothesis by comparing fledgling sex ratios in nests of first- and second-mated female house wrens (troglodytes aedon). in our wyoming population, second-mated females typically receive little or no male parental assistance and fledge fewer and lower-quality young compared with first-mated females. assuming that being of low ...200211886637
the energetic cost of begging behaviour in nestling house wrens.this study presents data relevant to the hypothesis that the energy expenditure associated with begging influences the signalling of need by nestling birds. we used open-circuit respirometry to measure the energy costs of resting, begging and non-begging activities in nestling house wrens, troglodytes aedon, ranging in age from 1 to 11 days post-hatching. across all ages, begging caused a 27% increase in metabolism above resting rates. the metabolic rate during begging was not related to begging ...19989642004
effects of the parasitic botfly philornis carinatus on nestling house wrens, troglodytes aedon, in costa rica.i studied the life cycle of a botfly (diptera: muscidae: philornis carinatus) and examined the effects of botfly ectoparasitism on nestling house wrens (passeriformes: troglodytidae: troglodytes aedon) during three years in costa rica. at three study sites, i found that nestlings were relatively unaffected by botflies, in contrast to all other studies of birds infected with philornid botflies. at monteverde, the main study site, infected chicks grew slightly slower and had slightly shorter tarsi ...199328313615
contribution of a mutational hot spot to hemoglobin adaptation in high-altitude andean house wrens.a key question in evolutionary genetics is why certain mutations or certain types of mutation make disproportionate contributions to adaptive phenotypic evolution. in principle, the preferential fixation of particular mutations could stem directly from variation in the underlying rate of mutation to function-altering alleles. however, the influence of mutation bias on the genetic architecture of phenotypic evolution is difficult to evaluate because data on rates of mutation to function-altering ...201526460028
spatial extent of mercury contamination in birds and their prey on the floodplain of a contaminated river.mercury (hg) exposure has been extensively studied in aquatic and piscivorous wildlife, but, historically, less attention has been directed towards terrestrial species. however, it has become apparent that aquatic hg crosses ecosystem boundaries along with beneficial subsidies, thereby entering the terrestrial food chain. it is still not known how far from contaminated waterways hg exposure remains a risk. we examined the spatial extent of exposure in terrestrial songbirds breeding in the floodp ...201829554763
borrelia genospecies in ixodes sp. cf. ixodes affinis (acari: ixodidae) from argentina.the aim of this work was to evaluate the presence of borrelia infection in ixodes sp. cf. ixodes affinis ticks from argentina. specimens of ixodes sp. cf. i. affinis were collected on vegetation and birds in five locations belonging the most humid part of the chaco biogeographic province. specimens were tested for borrelia infection by nested-pcr targeting the flab gene and the rrfa-rrlb intergenic spacer region (igs), sequenced and phylogenetically analyzed. a total of 48 ixodes sp. cf. i. affi ...202032993952
urban resources limit pair coordination over offspring provisioning.the amount of care parents provide to the offspring is complicated by an evolutionary conflict of interest ('sexual conflict') between the two parents. recent theoretical models suggest that pair coordination of the provisioning may reduce this conflict and increase parent and offspring fitness. despite empirical studies showing that pair coordination is common in avian species, it remains unclear how environmental and ecological conditions might promote or limit the ability of parents to coordi ...202032985594
connecting the dots: avian eggshell pigmentation, female condition and paternal provisioning effort.differences in avian eggshell pigmentation could be an honest signal of female quality that males use to inform their nestling provisioning effort. we investigated whether among-individual variation in protoporphyrin-based eggshell pigmentation in house wrens (troglodytes aedon) reflects female fitness-associated traits and whether males use that information. females laying lighter clutches were older and larger than females laying darker clutches. nestlings hatching from lighter clutches had gr ...202032394988
perceived threat to paternity reduces likelihood of paternal provisioning in house wrens.biparental care is a critical and, occasionally, unequally shared obligation that ensures that young survive to maturity. such care may be complicated in systems in which one parent, typically the male, is unsure of his genetic relatedness to the young. males may reduce paternal provisioning when full paternity is not assured, as occurs in mating systems in which females engage in extrapair copulations. moreover, other factors independent of extrapair matings, such as male personality traits, li ...202031579364
posthatching parental care and offspring growth vary with maternal corticosterone level in a wild bird population.corticosterone is the primary metabolic steroid in birds and is vital for maintaining homeostasis. however, the relationship between baseline corticosterone and reproduction is unclear, and we lack an understanding of how differences in baseline corticosterone at one stage of the breeding cycle influence reproductive effort at later stages. in a wild population of house wrens, we quantified the concentration of corticosterone in yolks of freshly laid eggs as an integrated measure of maternal phy ...202031393208
anthropogenic noise affects male house wren response to but not detection of territorial intruders.anthropogenic noise decreases signal active space, or the area over which male bird song can be detected in the environment. for territorial males, noise may make it more difficult to detect and assess territorial challenges, which in turn may increase defense costs and influence whether males maintain territory ownership. we tested the hypothesis that noise affects the ability of male house wrens (troglodytes aedon) near active nests to detect intruders and alters responses to them. we broadcas ...201931365593
genetic inheritance and environment determine endocrine plasticity to urban living.as urban areas continue to expand globally, understanding how and why species respond to novel habitats becomes increasingly important. knowledge of the mechanisms behind observed phenotypic changes in urban animals will enable us to better evaluate the impact of urbanization on current and future generations of wildlife. physiological changes, such as those involved in the endocrine stress response, may allow individuals to inhabit and thrive in urbanized areas, but it is currently unknown how ...201931362633
beak abnormality hinders provisioning ability and reduces body condition of a female house wren (troglodytes aedon).beak abnormalities have been reported in a wide range of species but typically affect only a small portion (<1%) of wild bird populations. most research has focused on the prevalence, morphology, and causes of beak deformities, resulting in relatively little information on the consequences of these deformities for individual birds. birds with abnormal beaks likely struggle to feed themselves, a situation that can only be exacerbated during the breeding season when they must provide food for not ...201931105481
condition-dependent begging elicits increased parental investment in a wild bird population.the coevolution of parental supply and offspring demand has long been thought to involve offspring need driving begging and parental care, leaving other hypotheses underexplored. in a population of wild birds, we experimentally tested whether begging serves as a negatively condition-dependent signal of need or a positively condition-dependent signal of quality. across multiple years, we supplemented nestling house wrens with food shortly after hatching and simultaneously manipulated corticostero ...201931002567
pre- and postnatal effects of experimentally manipulated maternal corticosterone on growth, stress reactivity and survival of nestling house wrens.corticosterone plays a central role in maintaining homeostasis, promoting energy acquisition, and regulating the stress response in birds. exposure to elevated levels of corticosterone during development can profoundly alter offspring behaviour and physiology, but the effects of elevated maternal corticosterone on offspring development remain poorly understood.we tested two competing hypotheses concerning the effect of maternally derived corticosterone on growth and development of free-living ho ...201830344358
experimental cross-fostering of eggs reveals effects of territory quality on reproductive allocation.parental and territory quality are often correlated in territorial birds, and both factors influence the resources allocated to offspring. surprisingly, the relative contribution of these two components of variation in parental investment remains obscure. we experimentally decoupled the normal covariation between parental quality and territory quality to test the hypothesis that territory quality influences female prenatal and postnatal reproductive allocation. territories were categorized into ...202030214135
experimental manipulation of incubation period reveals no apparent costs of incubation in house wrens.fitness costs of incubation ensue whenever the trade-off between incubation and foraging leads to suboptimal incubation or decreased parental body condition. we examined the costs of incubation in a wild population of house wrens, troglodytes aedon, by experimentally extending or decreasing the incubation period by cross-fostering eggs between nests at different stages of incubation (eggs from control nests were cross-fostered at the same stage of incubation). we determined whether parents or of ...201830026615
stressful city sounds: glucocorticoid responses to experimental traffic noise are environmentally dependent.a major challenge in urban ecology is to identify the environmental factors responsible for phenotypic differences between urban and rural individuals. however, the intercorrelation between the factors that characterize urban environments, combined with a lack of experimental manipulations of these factors in both urban and rural areas, hinder efforts to identify which aspects of urban environments are responsible for phenotypic differences. among the factors modified by urbanization, anthropoge ...201729046372
a new isosporoid coccidia (apicomplexa: eimeriidae)from the southern house wren troglodytes musculus naumann, 1823 (passeriformes: troglodytidae) from brazil.a new isosporoid coccidian species (protozoa: apicomplexa: eimeriidae) is reported from the southern house wren troglodytes musculus, a very well distributed species in south and central america. isospora corruirae sp. nov. oocysts are subspherical to ovoidal, 24.1 × 21.4 μm, with smooth, bilayered wall. micropyle and oocyst residuum are absent, but small spherules and splinter-like granules are frequently present. sporocysts are ovoidal to piriform, 14.0 × 9.5 μm. stieda body is prominent knob- ...201627078670
flexible responses to stage-specific offspring threats.when caring for their young, parents must compensate for threats to offspring survival in a manner that maximizes their lifetime reproductive success. in birds, parents respond to offspring threats by altering reproductive strategies throughout the breeding attempt. because altered reproductive strategies are costly, when threats to offspring are limited, parents should exhibit a limited response. however, it is unclear if response to offspring threat is the result of an integrated set of correl ...202031993114
mercury exposure and effects on cavity-nesting birds from the carson river, nevada.mercury (hg) concentrations were 15-40 times higher in the eggs and livers of tree swallows (tachycineta bicolor) and house wrens (troglodytes aedon) that nested along the carson river at and below dayton, nevada than in the same species above the mining-impacted areas. hg contamination was mainly the result of processing mills in the 1800s that used hg to separate gold and silver from ore. the exposure pattern of tree swallows and house wrens along the carson river was consistent with their tro ...200717083002
detection and transstadial passage of babesia species and borrelia burgdorferi sensu lato in ticks collected from avian and mammalian hosts in canada.lyme disease and human babesiosis are the most common tick-borne zoonoses in the temperate zone of north america. the number of infected patients has continued to rise globally, and these zoonoses pose a major healthcare threat. this tick-host-pathogen study was conducted to test for infectious microbes associated with lyme disease and human babesiosis in canada. using the flagellin (flab) gene, three members of the borrelia burgdorferi sensu lato (bbsl) complex were detected, namely a borrelia ...201931810270
detection of babesia odocoilei in ixodes scapularis ticks collected from songbirds in ontario and quebec, canada.songbirds widely disperse ticks that carry a diversity of pathogens, some of which are pathogenic to humans. among ticks commonly removed from songbirds, the blacklegged tick, ixodes scapularis, can harbor any combination of nine zoonotic pathogens, including babesia species. from may through september 2019, a total 157 ticks were collected from 93 songbirds of 29 species in the canadian provinces of ontario and québec. pcr testing for the 18s gene of babesia species detected babesia odocoilei i ...202032987727
why are tropical mountain passes "low" for some species? genetic and stable-isotope tests for differentiation, migration and expansion in elevational generalist songbirds.most tropical bird species have narrow elevational ranges, likely reflecting climatic specialization. this is consistent with janzen's rule, the tendency for mountain passes to be effectively "higher" in the tropics. hence, those few tropical species that occur across broad elevational gradients (elevational generalists) represent a contradiction to janzen's rule. here, we aim to address the following questions. are elevational generalists being sundered by diversifying selection along the gradi ...201729105758
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