Publications

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 ...	2020	32987727
detection and density of breeding marsh birds in iowa wetlands.	accounting for imperfect detection is an important process when obtaining estimates of density or abundance for breeding birds, and this is particularly true when researchers are monitoring birds to assess the success of restored wetlands. due to the dramatic decline in areal cover and habitat quality, wetland restoration in the prairie pothole region (ppr) is critically important to breeding birds. the shallow lakes restoration project (slrp), a partnership between the iowa department of natura ...	2020	31978167
wetland water-management may influence mercury bioaccumulation in songbirds and ducks at a mercury hotspot.	mercury is a persistent, biomagnifying contaminant that can cause negative behavioral, immunological, and reproductive effects in wildlife and human populations. we examined the role of wetland water-management on mercury bioaccumulation in songbirds and ducks at kellys slough national wildlife refuge complex, near grand forks, north dakota usa. we assessed mercury concentrations in blood of wetland-foraging songbirds (80 common yellowthroats [geothlypis trichas] and 14 nelson's sparrows [ammosp ...	2020	31902053
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 ...	2019	31810270
geolocator deployment reduces return rate, alters selection, and impacts demography in a small songbird.	in the past few years, miniature light-level geolocators have been developed for tracking wild bird species that were previously too small to track during their full annual cycle. geolocators offer an exciting opportunity to study the full annual cycle for many species. however, the potential detrimental effects of carrying geolocators are still poorly understood, especially for small-bodied birds. here, we deployed light-level geolocators on common yellowthroat warblers (geothlypis trichas). ov ...	2018	30540766
age and infection history are revealed by different ornaments in a warbler.	female preference for older or more disease-resistant males are both possible outcomes of parasite-mediated sexual selection, but the extent to which infection alters the development of ornaments to yield signals of male age and health has rarely been explored. in a longitudinal study of 61 male common yellowthroats (geothlypis trichas), age-related increases in the size of the melanin-based mask and carotenoid-based bib were not correlated among young males, likely owing to differences in how b ...	2018	30291422
major histocompatibility complex variation and blood parasites in resident and migratory populations of the common yellowthroat.	genes of the major histocompatibility complex (mhc) are a critical part of the adaptive immune response, and the most polymorphic genes in the vertebrate genome, especially in passerine birds. this diversity is thought to be influenced by exposure to pathogens which can vary in relation to numerous factors. migratory behaviour may be a particularly important trait to consider because migratory birds are exposed to a greater number of different pathogens and parasites at both breeding (i.e. tempe ...	2018	29964353
new feather mites of the genus <i>amerodectes</i> valim and hernandes (acariformes: proctophyllodidae) from passerines (aves: passeriformes) in georgia, usa.	eight new species of the feather mite genus amerodectes valim and hernandes, 2010 (proctophyllodidae: pterodectinae) are described from passerines (aves: passeriformes) in georgia, usa: amerodectes cathari sp. n. from catharus ustulatus (nuttall) (turdidae), a. haemorhous sp. n. from haemorhous mexicanus (muller, pls) (fringillidae), a. helmitheros sp. n. from helmitheros vermivorum (gmelin) (parulidae), a. hribari sp. n. from geothlypis trichas (linnaeus) (parulidae), a. hylocichlae sp. n. from ...	2017	29245629
age-specific patterns of infection with haemosporidians and trypanosomes in a warbler: implications for sexual selection.	although the selective loss of individuals susceptible to disease can favor the evolution of female preference for older males, the interrelationship between age, infection, longevity, and mating success remains poorly characterized in natural populations. in a longitudinal study of 61 male common yellowthroats (geothlypis trichas), we found that the probability of infection with hematozoa increased as males aged from 1 to 5 years. despite a significant, negative association between infection an ...	2017	28756490
sexual signals reflect telomere dynamics in a wild bird.	telomere dynamics in natural populations have been linked to survival, reproduction, and energetic investment. given their putative role in mediating life-history trade-offs, telomeres are also a likely candidate for maintaining honesty in sexually selected signals; few studies to date, however, have demonstrated a correlation between sexual signals and telomere dynamics. here, we show that plumage coloration in male common yellowthroats (geothlypis trichas) is correlated with both relative telo ...	2017	28515879
organophosphate pesticide method development and presence of chlorpyrifos in the feet of nearctic-neotropical migratory songbirds from canada that over-winter in central america agricultural areas.	recent modeling analysis suggests that numerous birds may be at risk of acute poisoning in insecticide-treated fields. although the majority of avian field studies on pesticides have focused on treated seed, granule, insect or vegetation (oral exposure) ingestion, dermal exposure is an important exposure route when birds come into contact with deposited pesticides on foliage and other surfaces. some nearctic-neotropical migratory songbirds are likely exposed to pesticides on their non-breeding h ...	2016	26421621
different ornaments signal male health and mhc variation in two populations of a warbler.	male traits that signal health and vigour are used by females to choose better quality mates, but in some cases the male trait selected by females differs among populations. multiple male traits can be maintained through female mate choice if both traits are equally honest indicators of male quality, but tests of this prediction are rare. by choosing males based on such traits, females could gain direct benefits from males (assistance with parental care), but when females choose extra-pair mates ...	2015	25728470
fluctuations in neighbourhood fertility generate variable signalling effort.	studies of sexual signalling generally focus on interactions between dyadic pairs, yet communication in natural populations often occurs in the context of complex social networks. the ability to survey social environments and adjust signal production appropriately should be a critical component of success in these systems, but has rarely been documented empirically. here, we used autonomous recording devices to identify 118 472 songs produced by 26 male common yellowthroats (geothlypis trichas) ...	2014	25339717
variation in plasma corticosterone in migratory songbirds: a test of the migration-modulation hypothesis.	physiological mechanisms underlying migration remain poorly understood, but recent attention has focused on the role of the glucocorticoid hormone corticosterone (cort) as a key endocrine regulator of migration. the migration-modulation hypothesis (mmh) proposes that baseline plasma cort levels are elevated in migratory birds to facilitate hyperphagia and lipogenesis and that further elevation of cort in response to acute stress is suppressed. consequently, cort may be a poor indicator of indivi ...	2014	25244381
an experimental test of the testosterone mediated oxidation handicap hypothesis in a wild bird.	the oxidation handicap hypothesis (ohh) proposed that honesty in sexual signals is maintained when testosterone simultaneously promotes the development of elaborate signals and imposes an oxidative cost. although there is evidence that testosterone enhances display traits in some cases, relatively few studies have tested the prediction that testosterone generates oxidative costs. we tested this prediction experimentally by administering testosterone (n=14) and control (n=14) implants to free-liv ...	2014	24907452
contrasting patterns of selection on the size and coloration of a female plumage ornament in common yellowthroats.	females often possess ornaments that appear smaller and duller than homologous traits in males. these ornaments may arise as nonfunctional by-products of sexual selection in males and cause negative viability or fecundity selection in females in proportion to the cost of their production and maintenance. alternatively, female ornaments may function as signals of quality that are maintained by sexual or social selection. in a 4-year study of 83 female common yellowthroats (geothlypis trichas) and ...	2014	24731149
spatial distribution of nests constrains the strength of sexual selection in a warbler.	in socially monogamous species, extra-pair paternity may increase the strength of intersexual selection by allowing males with preferred phenotypes to monopolize matings. several studies have found relationships between male signals and extra-pair mating, but many others fail to explain variation in extra-pair mating success. a greater appreciation for the role that ecological contingencies play in structuring behavioural processes may help to reconcile contradictory results. we studied extra-pa ...	2013	23639197
mhc variation is related to a sexually selected ornament, survival, and parasite resistance in common yellowthroats.	hamilton and zuk proposed that females choose mates based on ornaments whose expression is dependent on their genetically based resistance to parasites. the major histocompatibility complex (mhc) plays an important role in pathogen recognition and is a good candidate for testing the relationships between immune genes and both ornament expression and parasite resistance. we tested the hypothesis that female common yellowthroats prefer to mate with more ornamented males, because it is a signal of ...	2012	23461319
social and extra-pair mating in relation to major histocompatibility complex variation in common yellowthroats.	females are thought to gain better-quality genes for their offspring by mating with particular males. genes of the major histocompatibility complex (mhc) play a critical role in adaptive immunity, and several studies have examined female mate choice in relation to mhc variation. in common yellowthroats, females prefer males that have larger black facial masks, an ornament associated with mhc variation, immune function and condition. here we also tested whether mating patterns are directly correl ...	2012	23055067
songbird response to increased willow (salix spp.) growth in yellowstone's northern range.	after nearly a century of height suppression, willows (salix spp.) in the northern range of yellowstone national park, u.s.a., are increasing in height growth as a possible consequence of wolf (canis lupus) restoration, climate change, or other factors. regardless of the drivers, the recent release of this rare but important habitat type could have significant implications for associated songbirds that are exhibiting declines in the region. our objective was to evaluate bird response to releasin ...	2011	21939061
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 ...	2011	21864130
oxidative damage to dna related to survivorship and carotenoid-based sexual ornamentation in the common yellowthroat.	carotenoid-based sexual ornaments are hypothesized to be reliable signals of male quality, based on an allocation trade-off between the use of carotenoids as pigments and their use in antioxidant defence against reactive oxygen species. carotenoids appear to be poor antioxidants in vivo, however, and it is not clear whether variation in ornament expression is correlated with measures of oxidative stress (oxs) under natural conditions. we used single-cell gel electrophoresis to assay oxidative da ...	2011	21247942
highly variable acquisition rates of ixodes scapularis (acari: ixodidae) by birds on an atlantic barrier island.	acquisition of ticks by bird hosts is a central process in the transmission cycles of many tick-borne zoonoses, but tick recruitment by birds has received little direct study. we documented acquisition of ixodes scapularis say on birds at fire island, ny, by removing ticks from mist-netted birds, and recording the number of ticks on birds recaptured within 4 d of release. eight bird species acquired at least 0.8 ticks bird(-1) day(-1) during the seasonal peak for at least one age class of i. sca ...	2010	21175049
detection of lyme disease spirochete, borrelia burgdorferi sensu lato, including three novel genotypes in ticks (acari: ixodidae) collected from songbirds (passeriformes) across canada.	lyme disease is reported across canada, but pinpointing the source of infection has been problematic. in this three-year, bird-tick-pathogen study (2004-2006), 366 ticks representing 12 species were collected from 151 songbirds (31 passerine species/subspecies) at 16 locations canada-wide. of the 167 ticks/pools tested, 19 (11.4%) were infected with borrelia burgdorferi sensu lato (s.l.). sequencing of the rrf-rrl intergenic spacer gene revealed four borrelia genotypes: b. burgdorferi sensu stri ...	2010	20618658
extensive mhc class ii b gene duplication in a passerine, the common yellowthroat (geothlypis trichas).	the major histocompatibility complex (mhc) is characterized by a birth and death model of evolution involving gene duplication, diversification, loss of function, and deletion. as a result, gene number varies across taxa. birds have between one and 7 confirmed mhc class ii b genes, and the greatest diversity appears to occur in passerines. we used multiple primer sets on both genomic dna (gdna) and complementary dna (cdna) to characterize the range of class ii b genes present in a passerine, the ...	2010	20200139
sexual selection, multiple male ornaments, and age- and condition-dependent signaling in the common yellowthroat.	in many animals, sexual selection has resulted in complex signaling systems in which males advertise aspects of their phenotypic or genetic quality through elaborate ornamentation and display behaviors. different ornaments might convey different information or be directed at different receivers, but they might also be redundant signals of quality that function reliably at different times (ages) or in different contexts. we explored sexual selection and age- and condition-dependent signaling in t ...	2010	19863585
long-term effects of group-selection timber harvesting on abundance of forest birds.	relatively few studies have examined the ecological effects of group-selection timber harvesting, and nearly all have been short-term and have lacked experimental manipulations that allow pre- and posttreatment comparisons. we have been documenting the effects of a group-selection timber harvest on bird abundance in a maine forest for 24 years (preharvest, 1983-1987; postharvest, 1988-2006). here we characterized the trends in bird abundance over the first 20 years of the study in the managed an ...	2007	17883487
molecular identification of blood-meal sources in culiseta melanura and culiseta morsitans from an endemic focus of eastern equine encephalitis virus in new york.	eastern equine encephalitis (eee) virus perpetuates in an enzootic cycle involving ornithophilic mosquito vectors, principally culiseta melanura (coquillett) and avian amplification hosts. to better understand the role of cs. melanura and culiseta morsitans (theobald) in the epizootiology of eee virus, we collected blood-fed mosquitoes between 31 may and 15 october 2004 at two sites associated with an eee virus focus in central new york and identified the source of vertebrate blood by nucleotide ...	2006	17172382
immune response of nestling warblers varies with extra-pair paternity and temperature.	extra-pair mating is widespread in birds, but its adaptive function remains unclear. it is often suggested that females obtain superior genes for their offspring as a consequence of extra-pair mating, but the evidence is limited. in this study, we examined the hypothesis that extra-pair mating provides females with offspring that have superior immune responses. we found that the t-cell-mediated immune response of extra-pair young was stronger than that of within-pair young in common yellowthroat ...	2006	17032278
dual functions of a melanin-based ornament in the common yellowthroat.	melanin-based ornaments often function as signals in male-male competition, whereas carotenoid-based ornaments appear to be important in female mate choice. this difference in function is thought to occur because carotenoid pigments are more costly to produce than melanins and are thus more reliable indicators of male quality. we examined the role of melanin- and carotenoid-based ornaments in male-male competition and female choice in the common yellowthroat geothlypis trichas, a sexually dichro ...	2005	16024373
lutein-based plumage coloration in songbirds is a consequence of selective pigment incorporation into feathers.	many birds obtain colorful carotenoid pigments from the diet and deposit them into growing tissues to develop extravagant red, orange or yellow sexual ornaments. in these instances, it is often unclear whether all dietary pigments are used as integumentary colorants or whether certain carotenoids are preferentially excluded or incorporated into tissues. we examined the carotenoid profiles of three new world passerines that display yellow plumage coloration-the yellow warbler (dendroica petechia) ...	2003	12892761
birds disperse ixodid (acari: ixodidae) and borrelia burgdorferi-infected ticks in canada.	a total of 152 ixodid ticks (acari: ixodidae) consisting of nine species was collected from 82 passerine birds (33 species) in 14 locations in canada from 1996 to 2000. the lyme disease spirochete borrelia burgdorferi johnson, schmidt, hyde, steigerwaldt & brenner was cultured from the nymph of a blacklegged tick, ixodes scapularis say, that had been removed from a common yellowthroat, geothlypis trichas l., from bon portage island, nova scotia. as a result of bird movement, a nymphal i. scapula ...	2001	11476328
tick infestations of birds in coastal georgia and alabama.	mist-netted birds were examined for ticks on jekyll island, glynn co., georgia (32 bird species) in 1996-1998, and at fort morgan, baldwin co., alabama (36 species) in 1998 during fall migration. sixty-two (14.7%) of 423 birds from jekyll island and 22 (13.3%) of 165 birds from fort morgan were infested with ticks. the mean number of ticks per infested bird was 2.0 on jekyll island and 6.3 at fort morgan. ten species of birds were infested with ticks on jekyl1 island where 87% of all ticks were ...	2000	10780541
spring migratory birds (aves) extend the northern occurrence of blacklegged tick (acari:ixodidae).	birds that had migrated northward across lake superior were captured upon reaching landfall at thunder cape (48 degrees 18' n, 88 degrees 56' w) at the southwestern tip of the sibley peninsula, northwestern ontario, from 9 may to 9 june 1995. twenty-one of 530 birds examined (6 of 55 species) had a total of 34 ticks; 1 blue jay, cyanocitta cristata, had a northern fowl mite, ornithonyssus sylviarum (canestrini & fanzago). four blacklegged tick, ixodes scapularis say, larvae were found on an amer ...	1996	8699451
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 ...	1995	7650706
avian and mammalian hosts for spirochete-infected ticks and insects in a lyme disease focus in connecticut.	spirochetes and their vectors and reservoirs were studied in a lyme disease focus in east haddam, connecticut, from mid-may through september 1983. ixodes dammini subadults were comparable in number on white-footed mice (peromyscus leucopus) (means = 2.9 +/- 3.6 sd) to those on 27 different species of birds (means = 2.3 +/- 4.2 sd) representing 11 families within the order passeriformes. less commonly found ticks on birds (means less than or equal to 0.1) were immature ixodes dentatus and haemap ...	1984	6516460
involvement of birds in the epidemiology of the lyme disease agent borrelia burgdorferi.	borrelia burgdorferi, the causative agent of lyme disease, was isolated from the liver of a passerine bird, catharus fuscescens (veery), and from larval ixodes dammini (tick) feeding on pheucticus ludovicianus (rose-breasted grosbeak) and geothlypis trichas (common yellowthroat). in indirect immunofluorescence antibody tests, isolates reacted with polyclonal and monoclonal (h5332) antibodies. studies on the dna composition of the veery liver isolate and the strain cultured from an i. dammini lar ...	1986	3943893
incompetence of catbirds as reservoirs for the lyme disease spirochete (borrelia burgdorferi).	we compared the relative infectivity to vector ticks of gray catbirds (dumetella carolinensis) and white-footed mice (peromyscus leucopus) for the lyme disease spirochete (borrelia burgdorferi). of 28 catbirds captured in a site enzootic for this agent, 18 were infested by immature ixodes dammini, the tick vector. by comparison, each of 32 mice sampled concurrently from the same site was infested, and by about 10 times as many ticks as were found infesting the 3 most commonly netted bird species ...	1989	2918445
lyme disease and migrating birds in the saint croix river valley.	during a study of migrating land birds in 1987, we examined over 9,200 individual birds representing 99 species from the saint croix river valley, a lyme disease-endemic area of east central minnesota and northwestern wisconsin. we found that 250 deer tick (ixodes dammini) larvae and nymphs infested 58 birds from 15 migrant species; 56 ticks (22.4%) were positive for the lyme disease spirochete borrelia burgdorferi. five ground-foraging migrant bird species favoring mesic habitats, veery (cathar ...	1989	2782872