Publications

relation of lipid metabolism to migration in birds; seasonal variation in body lipids of the migratory white-throated sparrow.		1951	14853661
regulation of refractory period in the photoperiodic responses of the white-throated sparrow.		1958	13654678
thyroidal utilization of radioiodine in the white-throated sparrow and weaver finch.		1960	14410275
phosphatase activity and neuro-secretion in the hypothalamo-hypophyseal system in relation to the photoperiodic gonadal response in zonotrichia albicollis.		1962	14008062
chromosomal polymorphism in the white-throated sparrow, zonotrichia albicollis (gmelin).	in a study of 35 white-throated sparrows five distinct karyotypes were observed. a chromosomal polymorphism is present which involves at least two pairs of macrochromosomes. this species is phenotypically polymorphic with selective breeding occurring between morphs. phenotype is related to chromosomal constitution, and selective breeding appears to maintain heterozygosity within the population.	1966	17807298
antigonadal effects of prolactin in the white-throated sparrow, zonotrichia albicollis.		1969	5403617
seasonal variations in the diurnal rhythm of pituitary prolactin content in the white-throated sparrow, zonotrichia albicollis.		1969	5779820
effect of imidazole on bone 45ca release in white-throated sparrow, zonotrichia albicollis.		1970	5426566
temporal synergism of corticosterone and prolactin controlling fat storage in the white-throated sparrow, zonotrichia albicollis.		1971	5095207
diurnal and seasonal variations of plasma adrenal steroid hormone in the white-throated sparrow, zonotrichia albicollis.		1971	5087947
temporal synergism of corticosterone and prolactin controlling gonadal growth in sparrows.	gonadal growth was controlled in two avian species by corticosterone and prolactin injected daily at various times. testicular growth was induced in photorefractory house sparrows (passer domesticus) kept in continuous light by prolactin injected 4 or 8 hours after administration of corticosterone. other temporal patterns were ineffective. gonadal growth was also stimulated in photosensitive white-throated sparrows (zonotrichia albicollis) kept in continuous light by prolactin injected 12 hours ...	1971	5111566
dual hypothalamic feeding system in a migratory bird, zonotrichia albicollis.		1972	4569759
daily entrainment of the photoinducible phases for photostimulation of the reproductive system in the sparrows, zonotrichia albicollis and passer domesticus.		1973	4710782
residue accumulation in white-throated sparrows fed ddt for 5 and 11 weeks.		1974	4457180
a cytogenetic study of the white-throated sparrow, zonotrichia albicollis (gmelin).		1975	28563104
changes in the daily rhythm of plasma corticosterone concentration related to seasonal conditions in the white-throated sparrow, zonotrichia albicollis.	circadian variations in concentrations of plasma corticosterone were investigated in the white-throated sparrow maintained on short (10-hr) or long (16-hr) daily photoperiods. in addition, the plasma concentrations of corticosterone were determined throughout a day in birds that were in the reproductively photosensitive spring migratory condition, the reproductively photorefractory post nuptial molt condition, and the fall migratory condition. distinct unimodal rhythms were found in photosensiti ...	1975	1208548
daily rhythms of lipogenesis in fat and lean white-throated sparrows zonotrichia albicollis.	lipogenesis was assayed at 6 times a day in the migratory white-throated sparrow zonotrichia albicollis by measuring the incorporation of label in liver and body lipid 4 h after injection of [3h] acetate. there were daily rhythms of 3h incorporation by liver lipid both in fat birds in the vernal migratory condition and in lean birds in the summer photorefractory condition. most of the liver lipid incorporation of 3h was restricted to the late afternoon and early evening in both the fat and lean ...	1977	842625
lack of an effect of melatonin treatment via silastic capsules on photic-induced gonadal growth and the photorefractory condition in white-throated sparrows.		1978	656187
daily rhythm of plasma corticosterone binding activity in the white-throated sparrow, zonotrichia albicollis.		1978	565451
differential aggression in genetically different morphs of the white-throated sparros (zonotrichia albicollis).	to see if genetic differences correlate with differences in agonistic behavior, 225 encounters within and between color morphs of the white-throated sparrow (zonotrichia albicollis) were observed in feeding groups of different sizes and morphic compositions. tan morphs lack the m chromosome that replaces either of two chromosomes in the white morph. the data were analysed using quantitative models accounting for the proportions of morphs present, and the principal finding was that morphs are equ ...	1978	566001
interspecific and intraspecific song discrimination by zonotrichia albicollis and z. leucophrys.		1980	7427830
testosterone treatment blocks the termination of the gonadal photorefractory condition in white-throated sparrows maintained on short days.		1980	7409444
photoperiodic control of the timing of testicular regression in white-throated sparrows.		1982	7060930
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
plasma androgens and aggressiveness in captive winter white-throated sparrows (zonotrichia albicollis).	captive white-throated sparrows (zonotrichia albicollis), held under a natural photoperiod, were pair tested to evaluate dominance and aggressiveness in relation to plasma androgen levels and plumage morphology. androgen levels were determined in november, 1 week before behavioral testing began; in january, at the conclusion of behavioral testing; and again in march. november plasma androgen levels of captive birds did not differ from those of a group of feral birds and were greater than androge ...	1987	3610058
control of aggression and dominance in white-throated sparrows by testosterone and its metabolites.	in three experiments, we investigated whether testosterone itself or its metabolites activate aggression and dominance in white-throated sparrows zonotrichia albicollis. groups of five to six sparrows, each treated with a different steroid implanted subcutaneously, were observed in outdoor aviaries during late winter to determine the birds' rates of aggression (supplantations and attacks scaled to the number of available subordinates) and dominance rankings with opponents not previously encounte ...	1988	3235066
the effect of prolactin and cb154 on in vivo lipogenesis and enzyme patterns in the japanese quail, coturnix coturnix japonica and of photositmulation on enzyme patterns in the white-throated sparrow, zonotrichia albicollis.		1990	175996
borrelia burgdorferi in ticks (acari: ixodidae) from coastal virginia.	ixodid ticks removed from hosts and from vegetation during march-november 1987 at sites in coastal virginia and north carolina were examined for borrelia burgdorferi. b. burgdorferi was evident in nine (22%) ixodes cookei packard removed from rice rats (oryzomys palustris), a white-footed mouse (peromyscus leucopus), and raccoons (procyon lotor); four (6%) amblyomma americanum (l.) removed from raccoons; and two (3%) dermacentor variabilis (say) removed from a raccoon and a rice rat. b. burgdorf ...	1991	1941936
brain acetylcholinesterase activity in forest songbirds exposed to a new method of uulv fenitrothion spraying.	brain acetylcholinesterase (ache) activity was measured in forest songbirds exposed to ultra ultra low volume (uulv) aerial spraying of fenitrothion in new brunswick for spruce budworm control. brain ache activity was determined in 324 songbirds from the sprayed blocks and 47 from an unsprayed control area, and represented four species. in most cases, more than half of the individuals of any species sampled were diagnosed as "exposed" (greater than or equal to 20% inhibition) to the fenitrothion ...	1991	1996909
some platyhelminths inhabiting white-throated sparrows, zonotrichia albicollis (aves: emberizidae: emberizinae), from algonquin park, ontario, canada.	twenty-two of 26 white-throated sparrows, zonotrichia albicollis, from algonquin park, ontario, canada, hosted 1 or 2 species of platyhelminths. one species of cestode and 3 of digeneans were collected. anonchotaenia quiscali inhabited 50% of the sparrows. this is the third report of a. quiscali; z. albicollis is a new host. brachylecithum nanum inhabited 43%, zonorchis alveyi 15%, and prosthogonimus macrorchis 8% of the sparrows examined. ontario is a new geographic distribution record from all ...	1993	8331482
kinematics of birdsong: functional correlation of cranial movements and acoustic features in sparrows.	the movements of the head and beak of songbirds may play a functional role in vocal production by influencing the acoustic properties of songs. we investigated this possibility by synchronously measuring the acoustic frequency and amplitude and the kinematics (beak gape and head angle) of singing behavior in the white-throated sparrow (zonotrichia albicollis) and the swamp sparrow (melospiza georgiana). these birds are closely related emberizine sparrows, but their songs differ radically in freq ...	1993	8228778
adipose monoacylglycerol:acyl-coenzyme a acyltransferase activity in the white-throated sparrow (zonotrichia albicollis): characterization and function in a migratory bird.	although migrating birds use stored triacylglycerol as their primary fuel for flight, they must retain sufficient stores of omega 6 and omega 3 fatty acids to sustain reproduction after the spring migration. hepatic monoacylglycerol:acyl-coenzyme a acyltransferase (ec 2.3.1.22) (mgat) activity is associated with physiological periods in which lipolysis and beta-oxidation are prominent, and it may also play a role in the selective retention of certain essential fatty acids. therefore, we characte ...	1994	7869860
white-throated sparrow morphs that differ in song production rate also differ in the anatomy of some song-related brain areas.	white-throated sparrows are unusual among songbirds in that they occur in two color morphs, white-striped and tan-striped, determined by a chromosomal inversion and maintained by negative assortative mating. these differ in several reproductive behaviors, including amount of singing: white-striped males sing frequently, tan-striped females never sing, and tan-striped males and white-striped females sing an intermediate amount. the present study measures the volumes of several nuclei in the avian ...	1995	8537825
biomechanics of cranial kinesis in birds: testing linkage models in the white-throated sparrow (zonotrichia albicollis).	cranial kinesis in sparrows refers to the rotation of the upper jaw around its kinetic joint with the braincase. avian jaw mechanics may involve the coupled motions of upper and lower jaws, in which the postorbital ligament transfers forces from the lower jaw, through the quadrate, pterygoid, and jugal bones, to the upper jaw. alternatively, jaw motions may be uncoupled, with the upper jaw moving independently of the lower jaw. we tested hypotheses of cranial kinesis through the use of quantitat ...	1996	29852573
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
social inertia in white-throated sparrows results from recognition of opponents.	social inertia is a term for the stability of dominance relationships despite changes in the intrinsic dominating abilities of opponents. in a standard test for social inertia, low-ranking birds in an established hierarchy receive implants with testosterone (treated) and high-ranking birds receive empty implants (untreated). social inertia occurs when the treated birds remain subordinate to untreated opponents in these groups, despite evidence that similarly treated birds dominate untreated stra ...	1999	10049486
vocal tract function in birdsong production: experimental manipulation of beak movements.	kinematic analyses have demonstrated that the extent to which a songbird's beak is open when singing correlates with the acoustic frequencies of the sounds produced, suggesting that beak movements function to modulate the acoustic properties of the vocal tract during song production. if motions of the beak are necessary for normal song production, then disrupting the ability of a bird to perform these movements should alter the acoustic properties of its song. we tested this prediction by compar ...	2000	10821742
ticks (acari: ixodidae) and spirochetes (spirochaetaceae: spirochaetales) recovered from birds on a georgia barrier island.	from september 1997 through july 1999, 300 individuals and 46 species of birds were mist-netted and screened for ticks and spirochetes on st. catherine's island, liberty county, ga. seventy-six (25%) of the birds were parasitized by a meal intensity of 4.6 ticks. seasonally, more birds were infested with ticks during the summer (50% in 1998, 34% in 1999) than in spring (15% in 1998, 11% in 1999) or fall (21% in 1997, 20% in 1998), mainly because of severe infestations on some birds by immature s ...	2001	11296828
a behavior analysis of absolute pitch: sex, experience, and species.	absolute pitch (ap) perception refers to the ability to identify, classify, and memorize pitches without use of an external reference pitch. in tests of ap, several species were trained to sort contiguous tones into three or eight frequency ranges, based on correlations between responding to tones in each frequency range and reinforcement. two songbird species, zebra finches and white-throated sparrows, and a parrot species, budgerigars had highly accurate ap, they discriminated both three and e ...	2004	15157978
a field validation of plasma metabolite profiling to assess refueling performance of migratory birds.	plasma metabolite profiling offers a potential means to assess stopover refueling performance of migratory birds from a single capture. however, this method has not previously been validated where site quality has been determined independently using analysis of capture data. we captured and blood sampled six passerine bird species refueling at known high-quality (base) and low-quality (tip) sites at long point, ontario, canada. plasma triglyceride, an indicator of fat deposition, was higher at t ...	2005	15702470
stable isotopes in breath, blood, feces and feathers can indicate intra-individual changes in the diet of migratory songbirds.	we used stable isotopes of c in breath, blood, feces and feathers to identify intra-individual changes in diet and the timescale of diet changes in free-living songbirds at a stopover site. because accurate interpretation of differences between the delta13c of breath, plasma, and red blood cells (rbcs) relative to diet requires knowing the turnover rate of c within them, we determined the rate of change of c in breath, plasma and rbcs for yellow-rumped warblers (dendroica coronata). half-lives o ...	2005	15586297
mercury concentrations in bicknell's thrush and other insectivorous passerines in montane forests of northeastern north america.	anthropogenic input of mercury (hg) into the environment has elevated risk to fish and wildlife, particularly in northeastern north america. investigations into the transfer and fate of hg have focused on inhabitants of freshwater aquatic ecosystems, as these are the habitats at greatest risk for methylmercury (mehg) biomagnification. deviating from such an approach, we documented mehg availability in a terrestrial montane ecosystem using a suite of insectivorous passerines. intensive and extens ...	2005	15931968
neuroendocrine correlates of behavioral polymorphism in white-throated sparrows.	interspecific differences in the neuropeptide systems of the lateral septum (ls) often parallel differences in social behavior. in rodents, some closely related species that differ in aggressive behavior also differ according to the level of vasopressin (vp) innervation of the ls. in songbirds, the neuropeptides vasotocin (vt) and vasoactive intestinal peptide (vip) affect aggression when administered directly to the ls. here, we tested whether the density of vt or vip innervation of the ls refl ...	2005	15878570
stable isotope and band-encounter analyses delineate migratory patterns and catchment areas of white-throated sparrows at a migration monitoring station.	the canadian migration monitoring network consists of several fixed migration monitoring stations (mms) that apply constant-effort protocols to track changes in the abundance of migratory birds. such monitoring will be important for tracking long-term population trends of songbirds, especially for species breeding in remote areas such as the north american boreal forest. the geographical catchment sampled by individual mms, however, remains largely unknown. here, we used hydrogen isotope measure ...	2005	15800746
diet quality and food limitation affect the dynamics of body composition and digestive organs in a migratory songbird (zonotrichia albicollis).	migrating songbirds interrupt their feeding to fly between stopover sites that may vary appreciably in diet quality. we studied the effects of fasting and food restriction on body composition and digestive organs in a migratory songbird and how these effects interacted with diet quality to influence the rate of recovery of nutrient reserves. food limitation caused white-throated sparrows to reduce both lean and fat reserves, with about 20% of the decline in lean mass represented by a decline in ...	2006	15286920
estrogen-dependent selectivity of genomic responses to birdsong.	behavioral responses to sociosexual signals often depend on gonadal steroid hormones, which are thought to modulate behavior by acting on motivational systems in the brain. there is mounting evidence that sex steroids may also modulate perception of sociosexual signals by affecting sensory processing. in seasonally breeding songbirds such as the white-throated sparrow (zonotrichia albicollis), the female's behavioral response to hearing male song depends on her plasma levels of estradiol (e2). h ...	2006	16553615
endocrine correlates of alternative phenotypes in the white-throated sparrow (zonotrichia albicollis).	many vertebrate species exhibit alternative phenotypes (or morphs), in which one sex displays phenotypic variation equal to or greater than the variation between the sexes. males in such species typically display differences in reproductive strategies and morphology. steroid hormones such as testosterone are known modulators of reproductive behavior and morphology and therefore are obvious candidates for the mediation of phenotypic differences between morphs. we conducted a year-round study in t ...	2006	16919277
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
west nile virus surveillance in east baton rouge parish, louisiana.	west nile virus (wnv) was detected for the first time in louisiana in the fall of 2001. surveillance data collected from east baton rouge parish in 2002 were examined to establish baseline data on wnv activity, to support the current design of disease surveillance programs, and to target vector control efforts in the parish. the first indications of wnv activity were from a dead northern cardinal collected in february and from a live male cardinal sampled on 14 march. in mosquito pools, wnv was ...	2007	17536365
rapid neuroendocrine responses to auditory courtship signals.	in many species, courtship signals enhance reproductive function in the receiver. how these social signals are processed by the brain, particularly how they induce an endocrine response, is not well understood. songbirds provide an ideal model in which to study this phenomenon because of the large existing literature on both their auditory neurobiology and the control of their reproductive physiology by environmental cues. to date, all of the relevant studies on songbirds have involved measuring ...	2007	17823268
estradiol modulates brainstem catecholaminergic cell groups and projections to the auditory forebrain in a female songbird.	in songbirds, hearing conspecific song induces robust expression of the immediate early gene zenk in the auditory forebrain. this genomic response to song is well characterized in males and females of many species, and is highly selective for behaviorally relevant song. in white-throated sparrows, the selectivity of the zenk response requires breeding levels of estradiol; we previously showed that in non-breeding females with low levels of plasma estradiol, the zenk response to hearing song is n ...	2007	17764666
intraperitoneal delivery of exogenous corticosterone via osmotic pump in a passerine bird.	selecting the most reliable method to deliver exogenous steroids remains a problem for researchers, particularly when designing experiments on small birds. we used intraperitoneal (ip) osmotic pumps to deliver exogenous corticosterone (cort) and ru486 in captive white-throated sparrows. males received implants containing either a low (ld) or moderate dose (md) of cort, ru486 (ru), or polyethylene glycol vehicle only (v). this method provided sustained elevations in baseline cort in both ld and m ...	2007	17428484
estradiol modulates neural responses to song in a seasonal songbird.	social behaviors such as courtship, parenting, and aggression depend primarily on two factors: a social signal to trigger the behavior, and a hormonal milieu that facilitates or permits it. gonadal steroids may alter the valence or perceived context of the signal so that the same pheromone, vocalization, or visual display may elicit very different responses depending on the receiver's plasma hormone level. the neural processes underlying this phenomenon, however, are not well understood. here, w ...	2008	18770869
interaction of testosterone, corticosterone and corticosterone binding globulin in the white-throated sparrow (zonotrichia albicollis).	plasma binding globulins bind steroid hormones and are thought to regulate hormone access to tissues. mammals have both sex steroid binding globulin (ssbg) and corticosteroid binding globulin (cbg). birds, however, have no detectable ssbg, leading to the early conclusion that birds have no plasma regulation of sex steroids. cbg, however, can bind androgens with relatively high affinity. in birds, therefore, the control of androgenic effects may be tightly regulated by glucocorticoid physiology b ...	2008	18644248
endocrine and genomic architecture of life history trade-offs in an avian model of social behavior.	life history trade-offs can drive the evolution of alternative phenotypes, the expression of which is usually under hormonal control. here, i review the endocrine and genetic bases of a trade-off between parental and competitive behavior in an increasingly popular model of social behavior, the white-throated sparrow (zonotrichia albicollis). within a population, approximately half of the individuals of this species exhibit a tan stripe (ts) on the crown and adopt a parental strategy, whereas the ...	2008	18495122
activity of the hypothalamic-pituitary-gonadal axis differs between behavioral phenotypes in female white-throated sparrows (zonotrichia albicollis).	the white-throated sparrow (zonotrichia albicollis) lends itself particularly well to investigations of neuroendocrine mechanisms of social behavior because of a behavioral polymorphism that correlates with a plumage phenotype. roughly half of the individuals of this species exhibit a white stripe (ws) on the crown and engage in a more aggressive strategy, whereas the other half exhibit a tan stripe (ts) and assume a more parental strategy. these behavioral differences are mirrored by hormonal a ...	2008	18275963
impacts of chronic anthropogenic noise from energy-sector activity on abundance of songbirds in the boreal forest.	the effects of human activities in forests are often examined in the context of habitat conversion. changes in habitat structure and composition are also associated with increases in the activity of people with vehicles and equipment, which results in increases in anthropogenic noise. anthropogenic noise may reduce habitat quality for many species, particularly those that rely on acoustic signals for communication. we compared the density and occupancy rate of forest passerines close to versus f ...	2008	18616740
the chromosomal polymorphism linked to variation in social behavior in the white-throated sparrow (zonotrichia albicollis) is a complex rearrangement and suppressor of recombination.	variation in social behavior and plumage in the white-throated sparrow (zonotrichia albicollis) is linked to an inversion polymorphism on chromosome 2. here we report the results of our comparative cytogenetic mapping efforts and population genetics studies focused on the genomic characterization of this balanced chromosomal polymorphism. comparative chromosome painting and cytogenetic mapping of 15 zebra finch bac clones to the standard (zal2) and alternative (zal2(m)) arrangements revealed tha ...	2008	18562641
the value of avian genomics to the conservation of wildlife.	genomic studies in non-domestic avian models, such as the california condor and white-throated sparrow, can lead to more comprehensive conservation plans and provide clues for understanding mechanisms affecting genetic variation, adaptation and evolution.developing genomic tools and resources including genomic libraries and a genetic map of the california condor is a prerequisite for identification of candidate loci for a heritable embryonic lethal condition. the white-throated sparrow exhibits ...	2009	19607652
vocal tract motor patterns and resonance during constant frequency song: the white-throated sparrow.	bird song is a complex behavior that requires the coordination of several motor systems. sound is produced in the syrinx and then modified by the upper vocal tract. movements of the hyoid skeleton have been shown in the northern cardinal (cardinalis cardinalis) to be extensively involved in forming an oropharyngeal-esophageal cavity (oec), which contributes a major resonance to the vocal tract transfer function. here we report that a similar relationship exists between the volume of the oec and ...	2009	19082607
neural distribution of nonapeptide binding sites in two species of songbird.	vasotocin (vt) and its mammalian homologue, vasopressin (vp), modulate many social behaviors in a variety of vertebrate species. in songbirds, the effects of centrally administered vt vary according to species, which may reflect species-specific distributions of vt binding sites. different radioligands used to map receptors in previous autoradiographical studies have revealed nonoverlapping distributions of vt binding, suggesting a heterogeneous population of more than one type of vt receptor. f ...	2009	19132730
examining the social landscapes of alternative reproductive strategies.	social environments are inherently dynamic, often changing depending on the frequency and outcomes of conspecific interactions - they can be simultaneously the targets and agents of selection. understanding how organisms settle in heterogeneous social environments and the effects this has on reproductive success is vital to our understanding of the selective forces at work in wild populations. from an intensive behavioural and ecological study of territoriality in the polymorphic white-throated ...	2009	19878503
corticosterone manipulations alter morph-specific nestling provisioning behavior in male white-throated sparrows, zonotrichia albicollis.	in the polymorphic white-throated sparrow (zonotrichia albicollis), tan-striped males provision nestlings at higher rates than do white-striped males. in a previous study, we found that tan-striped males had lower baseline corticosterone levels than white-striped males during the nestling stage. to determine if this variation in corticosterone influences morph-specific differences in nestling provisioning behavior, we used intraperitoneal osmotic pumps to increase baseline corticosterone levels ...	2009	19751738
seasonal upregulation of fatty acid transporters in flight muscles of migratory white-throated sparrows (zonotrichia albicollis).	endurance flights of birds, some known to last several days, can only be sustained by high rates of fatty acid uptake by flight muscles. previous research in migratory shorebirds indicates that this is made possible in part by very high concentrations of cytosolic heart-type fatty acid binding protein (h-fabp), which is substantially upregulated during migratory seasons. we investigated if h-fabp and other components of muscle fatty acid transport also increase during these seasons in a passerin ...	2009	19717675
fatty acid composition of pectoralis muscle membrane, intramuscular fat stores and adipose tissue of migrant and wintering white-throated sparrows (zonotrichia albicollis).	the fatty acid composition of muscle membrane phospholipids and fat stores may affect migration performance in birds. the purpose of this study was to investigate seasonal changes in the fatty acid composition of (1) pectoralis muscle phospholipids, (2) intramuscular triglyceride stores and (3) adipose tissue triglycerides in free-living white-throated sparrows (zonotrichia albicollis). during migratory seasons there was an increase in the n-6:n-3 ratio of muscle membrane phospholipid fatty acid ...	2009	19915129
the effect of muscle phospholipid fatty acid composition on exercise performance: a direct test in the migratory white-throated sparrow (zonotrichia albicollis).	dietary polyunsaturated fatty acids (pufa) can have various effects on animal physiology through their roles as energy, structural, regulatory, and signaling molecules. of recent interest has been the incorporation of dietary pufa into muscle membranes as phospholipids, thereby potentially affecting exercise performance by mechanisms such as altered mitochondrial proton leak and membrane-bound protein activity. we first studied the effects of a high-omega6 pufa diet vs. a high-omega3 pufa diet o ...	2009	19587112
dietary macronutrients affect lipid metabolites and body composition of a migratory passerine, the white-throated sparrow (zonotrichia albicollis).	plasma lipid metabolites can provide information about fat metabolism and storage in migrating birds, yet little is known about the influence of diet and nutrition or how they relate to intraindividual differences in body composition of songbirds. we investigated how dietary macronutrient composition affects plasma lipid concentrations and subsequent changes in fat accumulation in white-throated sparrows (zonotrichia albicollis). birds fed a low-protein diet with more glucose had higher plasma t ...	2009	19331582
behavioral phenotypes persist after gonadal steroid manipulation in white-throated sparrows.	white-throated sparrows (zonotrichia albicollis) exhibit a behavioral polymorphism that segregates with a plumage marker. individuals with a white stripe (ws) on the crown engage in an aggressive strategy that involves more singing, whereas individuals with a tan stripe (ts) sing less and engage in more parental care. previous work has shown that plasma levels of gonadal steroids differ between the morphs in both sexes, suggesting a hormonal mechanism for the polymorphic behavior in this species ...	2009	18848562
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
topography of estradiol-modulated genomic responses in the songbird auditory forebrain.	sex steroids facilitate dramatic changes in behavioral responses to sociosexual signals and are increasingly implicated in the sensory processing of those signals. our previous work demonstrated that in female white-throated sparrows, which are seasonal breeders, genomic responses in the auditory forebrain are selective for conspecific song over frequency-matched tones only when plasma estradiol (e2) reaches breeding levels. here, we sought to map this e2-dependent selectivity in the best-studie ...	2010	19885833
contrasting population genetic patterns within the white-throated sparrow genome (zonotrichia albicollis).	the level of nucleotide diversity observed across the genome is positively correlated with the local rate of recombination. avian karyotypes are typified by large variation in chromosome size and the rate of recombination in birds has been shown to be negatively correlated with chromosome size. it has thus been predicted that nucleotide diversity is negatively correlated with chromosome size in aves. however, there is limited empirical evidence to support this prediction.	2010	21029465
chromosome-wide linkage disequilibrium caused by an inversion polymorphism in the white-throated sparrow (zonotrichia albicollis).	chromosomal inversions have been of long-standing interest to geneticists because they are capable of suppressing recombination and facilitating the formation of adaptive gene complexes. an exceptional inversion polymorphism (zal2(m)) in the white-throated sparrow (zonotrichia albicollis) is linked to variation in plumage, social behavior and mate choice, and is maintained in the population by negative assortative mating. the zal2(m) polymorphism is a complex inversion spanning > 100 mb and has ...	2010	20571514
gonadotrophin-releasing hormone neurons in a photoperiodic songbird express fos and egr-1 protein after a single long day.	birds use a variety of environmental cues, such as day length, temperature and social interactions, to time reproductive efforts. for most seasonally breeding birds, day length is the most important cue and takes precedence over all others. experimental manipulation of day length has shown that, in a number of galliformes and passeriformes, exposure to a single long day induces a rise in plasma luteinising hormone (lh). the mechanisms underlying this response are only beginning to be understood. ...	2010	20070482
evolution of a bitter taste receptor gene cluster in a new world sparrow.	bitter taste perception likely evolved as a protective mechanism against the ingestion of harmful compounds in food. the evolution of the taste receptor type 2 (tas2r) gene family, which encodes the chemoreceptors that are directly responsible for the detection of bitter compounds, has therefore been of considerable interest. though tas2r repertoires have been characterized for a number of species, to date the complement of tas2rs from just one bird, the chicken, which had a notably small number ...	2010	20624740
a w-linked palindrome and gene conversion in new world sparrows and blackbirds.	a hallmark feature of the male-specific region of the human y chromosome is the presence of large and near-identical palindromes. these palindromes are maintained in a state of near identity via gene conversion between the arms of the palindrome, and both neutral and selection-based theories have been proposed to explain their enrichment on the human y and x chromosomes. while those proposed theories would be applicable to sex chromosomes in other species, it has not been established whether nea ...	2010	20535633
migration- and exercise-induced changes to flight muscle size in migratory birds and association with igf1 and myostatin mrna expression.	seasonal adjustments to muscle size in migratory birds may result from preparatory physiological changes or responses to changed workloads. the mechanisms controlling these changes in size are poorly understood. we investigated some potential mediators of flight muscle size (myostatin and insulin-like growth factor, igf1) in pectoralis muscles of wild wintering or migrating white-throated sparrows (zonotrichia albicollis), captive white-throated sparrows that were photoperiod manipulated to be i ...	2011	21832125
quantitative magnetic resonance analysis and a morphometric predictive model reveal lean body mass changes in migrating nearctic-neotropical passerines.	most studies of lean mass dynamics in free-living passerine birds have focused on old world species at geographical barriers where they are challenged to make the longest non-stop flight of their migration. we examined lean mass variation in new world passerines in an area where the distribution of stopover habitat does not require flights to exceed more than a few hours and most migrants stop flying well before fat stores near exhaustion. we used either quantitative magnetic resonance (qmr) ana ...	2011	21079970
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
comparative bac-based mapping in the white-throated sparrow, a novel behavioral genomics model, using interspecies overgo hybridization.	abstract:	2011	21693052
carnitine palmitoyl transferase activity and whole muscle oxidation rates vary with fatty acid substrate in avian flight muscles.	birds primarily fuel migratory flights with fat, and the composition of that fat has the potential to affect overall lipid oxidation rates. we measured the whole muscle lipid oxidation rates in extensor digitorum communis muscles from white-throated sparrows (zonotrichia albicollis gmelin) incubated for 20 min at 20°c with radiolabeled stearate (18:0), oleate (18:1ω9), or linoleate (18:2ω6). lipid oxidation rates were ~40% higher with linoleate than oleate (oleate: 36 ± 8.54 μmol co(2) g(-1) h(- ...	2011	21153644
neural distribution of vasotocin receptor mrna in two species of songbird.	the neurohypophyseal hormones vasopressin and oxytocin are produced and released within the mammalian brain, where they act via multiple receptor subtypes. the neural distributions of these receptors, for example, v1a and oxytocin receptors, have been well described in many mammals. in birds, the distribution of binding sites for the homologous neuropeptides, vasotocin (vt) and mesotocin, has been studied in several species by using synthetic radioligands designed to bind to mammalian receptors. ...	2011	22067316
behavioral and physiological effects of photoperiod-induced migratory state and leptin on a migratory bird, zonotrichia albicollis: i. anorectic effects of leptin administration.	the hormone leptin is involved in the regulation of energy balance in mammals, mainly by reducing food intake and body adiposity and increasing energy expenditure. during energetically demanding periods, leptin's action is often altered to facilitate fat deposition and maintain high rates of food intake. despite the present controversy over the existence of an avian leptin, there is evidence that a leptin receptor exists in birds and its activation influences energy intake and metabolism. howeve ...	2011	21925179
behavioral and physiological effects of photoperiod-induced migratory state and leptin on zonotrichia albicollis: ii. effects on fatty acid metabolism.	the migratory flights of birds are fuelled largely by fatty acids. fatty acid transporters, including fat/cd36, fabppm and h-fabp, and enzymes involved in fatty acid oxidation (cpt, cs, hoad) are seasonally up-regulated in flight muscle to meet the demands of this intense aerobic exercise. the mechanisms that control these biochemical changes in response to migration are mostly unknown. we studied the effects of a photoperiod-induced migratory state and a 7 day treatment with murine leptin (1 μg ...	2011	21925178
combining stable-isotope (deltad) and band recovery data to improve probabilistic assignment of migratory birds to origin.	the recent application of stable-isotope analyses, particularly the use of stable-hydrogen-isotope (deltad) measurements of animal tissues, has greatly improved our ability to infer geographic origins of migratory animals. however, many individual sources of error contribute to the overall error in assignment; thus likelihood-based assignments incorporating estimates of error are now favored. in addition, globally, the nature of the underlying precipitation-based deltad isoscapes is such that lo ...	2011	21774434
estradiol-dependent catecholaminergic innervation of auditory areas in a seasonally breeding songbird.	a growing body of evidence suggests that gonadal steroids such as estradiol (e2) alter neural responses not only in brain regions associated with reproductive behavior but also in sensory areas. because catecholamine systems are involved in sensory processing and selective attention, and because they are sensitive to e2 in many species, they may mediate the neural effects of e2 in sensory areas. here, we tested the effects of e2 on catecholaminergic innervation, synthesis and activity in the aud ...	2011	21714815
morph matters: aggression bias in a polymorphic sparrow.	in species with discrete morphs exhibiting alternative behavioral strategies, individuals may vary their aggressive behavior in competitive encounters according to the phenotype of their opponent. such aggression bias has been documented in multiple polymorphic species evolving under negative frequency-dependent selection, but it has not been well-studied under other selection regimes. we investigated this phenomenon in white-throated sparrows (zonotrichia albicollis), a passerine with plumage p ...	2012	23119092
rapid effects of hearing song on catecholaminergic activity in the songbird auditory pathway.	catecholaminergic (ca) neurons innervate sensory areas and affect the processing of sensory signals. for example, in birds, ca fibers innervate the auditory pathway at each level, including the midbrain, thalamus, and forebrain. we have shown previously that in female european starlings, ca activity in the auditory forebrain can be enhanced by exposure to attractive male song for one week. it is not known, however, whether hearing song can initiate that activity more rapidly. here, we exposed es ...	2012	22724011
estradiol-dependent modulation of serotonergic markers in auditory areas of a seasonally breeding songbird.	because no organism lives in an unchanging environment, sensory processes must remain plastic so that in any context, they emphasize the most relevant signals. as the behavioral relevance of sociosexual signals changes along with reproductive state, the perception of those signals is altered by reproductive hormones such as estradiol (e2). we showed previously that in white-throated sparrows, immediate early gene responses in the auditory pathway of females are selective for conspecific male son ...	2012	21942431
birdsong: is it music to their ears?	since the time of darwin, biologists have wondered whether birdsong and music may serve similar purposes or have the same evolutionary precursors. most attempts to compare song with music have focused on the qualities of the sounds themselves, such as melody and rhythm. song is a signal, however, and as such its meaning is tied inextricably to the response of the receiver. imaging studies in humans have revealed that hearing music induces neural responses in the mesolimbic reward pathway. in thi ...	2012	23226128
spatial, temporal, molecular, and intraspecific differences of haemoparasite infection and relevant selected physiological parameters of wild birds in georgia, usa.	the prevalence of five avian haemoparasite groups was examined for effects on health and associations with extrinsic factors. overall, 786 samples were examined from six sites in two georgia (usa) watersheds, during breeding and non-breeding periods in 2010 and 2011. among the four most commonly infected species, haemoproteus prevalence was significantly higher in northern cardinals (cardinalis cardinalis) compared to indigo buntings (passerina cyanea) and tufted titmice (baeolophus bicolor) whi ...	2013	24533333
differential regulation of adipokines may influence migratory behavior in the white-throated sparrow (zonotrichia albicollis).	white-throated sparrows increase fat deposits during pre-migratory periods and rely on these fat stores to fuel migration. adipose tissue produces hormones and signaling factors in a rhythmic fashion and may be controlled by a clock in adipose tissue or driven by a master clock in the brain. the master clock may convey photoperiodic information from the environment to adipose tissue to facilitate pre-migratory fattening, and adipose tissue may, in turn, release adipokines to indicate the extent ...	2013	23785393
testosterone alters genomic responses to song and monoaminergic innervation of auditory areas in a seasonally breeding songbird.	behavioral responses to social stimuli often vary according to endocrine state. our previous work has suggested that such changes in behavior may be due in part to hormone-dependent sensory processing. in the auditory forebrain of female white-throated sparrows, expression of the immediate early gene zenk (egr-1) is higher in response to conspecific song than to a control sound only when plasma estradiol reaches breeding-typical levels. estradiol also increases the number of detectable noradrene ...	2013	23362219
oxidative stress, circulating antioxidants, and dietary preferences in songbirds.	oxidative stress is an unavoidable consequence of metabolism and increases during intensive exercise. this is especially problematic for migratory birds that metabolize fat to fuel long-distance flight. birds can mitigate damage by increasing endogenous antioxidants (e.g. uric acid) or by consuming dietary antioxidants (e.g. tocopherol). during flight, birds may increase protein catabolism of lean tissue which may increase circulating uric acid and many birds also consume an antioxidant-rich fru ...	2013	23270695
behavioral characterization of a white-throated sparrow homozygous for the zal2(m) chromosomal rearrangement.	the white-throated sparrow is rapidly becoming an important model in the genetics of social behavior because of a chromosomal rearrangement that segregates with a behavioral phenotype. within a population, 50 % of individuals are heterozygous for a rearranged chromosome 2 (zal2(m)). these birds sing more and are more aggressive than the other 50 %, who lack the rearrangement. a disassortative mating system, in which heterozygotes almost never interbreed, ensures that zal2(m)/2(m) homozygotes are ...	2013	23264208
plasma testosterone correlates with morph type across breeding substages in male white-throated sparrows.	white-throated sparrows (zonotrichia albicollis) exhibit a genetic polymorphism that affects plumage and behavior in both sexes. white-striped morphs are more territorially aggressive, whereas tan-striped morphs provision nestlings at a higher rate. we investigated testosterone physiology in this species in an effort to understand hormonal mechanisms for the observed differences in aggression and parental care between the morphs. we found a small but significant difference in plasma testosterone ...	2013	19637970
evaluation of reference genes for quantitative real-time pcr in the brain, pituitary, and gonads of songbirds.	quantitative real-time pcr (qpcr) is becoming a popular tool for the quantification of gene expression in the brain and endocrine tissues of songbirds. accurate analysis of qpcr data relies on the selection of appropriate reference genes for normalization, yet few papers on songbirds contain evidence of reference gene validation. here, we evaluated the expression of ten potential reference genes (18s, actb, gapdh, hmbs, hprt, ppia, rpl4, rpl32, tfrc, and ubc) in brain, pituitary, ovary, and test ...	2014	24780145
timing of feather molt related to date of spring migration in male white-throated sparrows, zonotrichia albicollis.	in migratory birds, the ability to depart wintering grounds at the appropriate time is an important determinant of fitness. understanding the regulation of this timing will be essential for predicting whether timing of bird migration keeps up with global climate change. we examined whether the timing of the late-winter molt, in which white-throated sparrows (zonotrichia albicollis) replace head and body feathers in advance of mating, may constrain the timing of northward migratory departure. in ...	2014	25287905
variation in preen oil composition pertaining to season, sex, and genotype in the polymorphic white-throated sparrow.	evidence for the the ability of birds to detect olfactory signals is now well documented, yet it remains unclear whether birds secrete chemicals that can be used as social cues. a potential source of chemical cues in birds is the secretion from the uropygial gland, or preen gland, which is thought to waterproof, maintain, and protect feathers from ectoparasites. however, it is possible that preen oil also may be used for individual recognition, mate choice, and signalling social/sexual status. i ...	2014	25236380
new insights into the hormonal and behavioural correlates of polymorphism in white-throated sparrows, zonotrichia albicollis.	the white-throated sparrow is a promising model for behavioural neuroendocrinology and genetics because behaviour and endocrine function may be linked to a chromosomal rearrangement that determines plumage colour. the notion that the two colour morphs, tan-striped (ts) and white-striped (ws), differ predictably in aggression and parenting has been widely accepted, despite conflicting evidence. it is also hypothesized that morph-typic behaviour is hormone mediated, yet no field study has measured ...	2014	25045171
sex steroid-independent effects of photostimulation on the song-control system of white-throated sparrows (zonotrichia albicollis).	brain nuclei within the song-control system of songbirds are seasonally plastic during adulthood. these nuclei are larger in birds exposed to long, spring-like days than short, winter-like days. there is overwhelming evidence that this effect is mediated by testosterone (t). however, castration studies have also demonstrated that photostimulation has gonad-independent effects on song-control system plasticity, but these studies rarely control for extra-gonadal sources of t. in this study, we use ...	2014	24818971