| hepatic microsomal n-hydroxylation of p-chloroaniline and p-chloro-n-methylaniline in red-winged blackbird compared with rat. | 1. n-hydroxylation of p-chloroaniline (pca) and p-chloro-n-methylaniline (pcma) was measured in red-winged blackbird (agelaius phoeniceus) and rat (rattus norvegicus) hepatic microsomes. 2. redwing hepatic microsomes n-hydroxylated pca slower than rat microsomes. furthermore, redwing hepatic microsomes had marginal or no ability to n-hydroxylate pcma, whereas rat hepatic microsomes n-hydroxylated pcma at a higher rate than pca. 3. the bird hepatic microsomes had only low or marginal n-demethylas ... | 1979 | 40352 |
| experimental newcastle disease virus infections in three species of wild birds. | three species of wild birds--the red-winged blackbird (agelaius phoeniceus), an african weaver finch (quelea quelea), and the sandhill crane (grus canadensis)--were exposed to newcastle disease virus (ndv) to determine susceptibility and host response. the ndv used were a vaccine strain (lasota) and a viscerotropic velogenic strain (new york parrot). host response was monitored by virus isolation, signs of disease, and serologic response. both the red-winged blackbirds and the quelea shed little ... | 1979 | 486009 |
| life history and host specificity of mediorhynchus centurorum nickol 1969 (acanthocephala: gigantorhynchidae). | examination of 1905 arthropods from a swamp and surrounding pasture in sothern louisiana revealed larval specimens of mediorhynchus centurorum in 8 of 228 woodroaches, parcoblatta pensylvanica, but in no other species. the life cycle was confirmed by feeding eggs of m. centurorum to laboratory-reared woodroaches. cystacanths later recovered from the woodroaches developed into mature worms when pipetted into esophaguses of red-bellied woodpeckers, centurus carolinius: red-headed woodpeckers, mela ... | 1977 | 845719 |
| hepatic microsomal n-oxidation and n-demethylation of n,n-dimethylaniline in red-winged blackbird compared with rat and other birds. | | 1975 | 1207400 |
| community ecology of helminth parasitism in an insular passerine avifauna. | three hundred and thirty specimens of 7 species of passerine birds from south bass island, ottawa county, ohio, were examined for helminth parasites. the total number of helminth specimens collected was 4,333. forty-one helminth taxa were identified. ten species of helminths were identified as having foci of infection on the island. an index of association for these 10 species is presented. the low association revealed between helminth species utilizing common species of intermediate hosts indic ... | 1976 | 1255354 |
| altered daylength affects dendritic structure in a song-related brain region in red-winged blackbirds. | substantial neural and behavioral plasticity occurs in the avian song system in adulthood. changes in the volume of one of the song control nuclei, robustus archistriatalis (ra), have been associated with seasonal changes in singing behavior in adult canaries (serinus canarius) and red-winged blackbirds (agelaius phoeniceus). the present work assessed the effects of changed daylength on dendritic morphology in ra in adult male red-winged blackbirds. brains from hand-reared red-winged blackbirds ... | 1991 | 1759944 |
| effects of noise on pure-tone thresholds in blackbirds (agelaius phoeniceus and molothrus ater) and pigeons (columba livia). | blackbirds and pigeons were trained to detect tones in quiet and in broadband noise by using positive-reinforcement techniques. in experiment 1, thresholds in noise were obtained in blackbirds as a function of both tone frequency and noise intensity for a pulsed noise masker (noise gated on and off with tone). for blackbirds, critical ratios (the ratio of the power of the just-detectable tone in noise to the power of the noise masker) obtained in pulsed noise showed no consistent relation to ton ... | 1987 | 3568604 |
| modes of perceiving and processing information in birdsong (agelaius phoeniceus, molothrus ater, and homo sapiens). | in a previous study i examined the abilities of red-winged blackbirds and brown-headed cowbirds trained with a go-right/go-left procedure to identify conspecific and alien song themes (sinnott, 1980). results showed that each bird species exhibited superior identification of conspecific final "trill" or "whistle" elements, relative to the alien species. the present study extends these results by examining human perception of these same song stimuli, by examining the effects of tutoring birds wit ... | 1987 | 3691059 |
| experimental infection and serologic survey for selected paramyxoviruses in red-winged blackbirds (agelaius phoeniceus). | red-winged blackbirds (agelaius phoeniceus) were experimentally exposed to three avian paramyxoviruses: turkey parainfluenza virus, yucaipa virus, and two strains of newcastle disease virus. aerosol exposure resulted in infection but exposure in food or drinking water rarely or never did. tracheal swabs contained virus for up to eight days post exposure, cloacal swabs were negative. transmission to contact birds occurred infrequently. antibody response was of low titer and short duration. no hem ... | 1980 | 6246286 |
| oxychlordane, hcs-3260, and nonachlor in birds: lethal residues and loss rates. | oxychlordane reached lethal levels in birds given dietary dosages of hcs-3260 (70.75% cis-chlordane and 23.51% trans-chlordane) at 6 levels from 50 to 500 ppm. oxychlordane ranged from 9.4 to 22.1 ppm in brains of cowbirds (molothrus ater), grackles (quiscalus quiscula), and red-winged blackbirds (agelaius phoeniceus) that died on dosage and from 1.3 to 4.8 ppm in sacrificed birds, providing a clear diagnostic separation. among starlings (sturnus vulgaris), however, oxychlordane ranged from 5.0 ... | 1983 | 6668611 |
| aspects of frequency discrimination in passerine birds and pigeons. | with the use of a positive reinforcement operant technique, pulsed-tone, frequency difference limens (dls) were measured in two icterid passerine species, the redwing blackbird (agelaius phoeniceus) and the brown-headed cowbird (molothrus ater). direct comparisons were made with two nonpasserine control (pigeon) subjects. blackbirds were more sensitive than pigeons to frequency changes above 1.0 khz but less sensitive below 1.0 khz. measured dls in all these birds were within the range of nonhum ... | 1980 | 7391279 |
| females have a larger hippocampus than males in the brood-parasitic brown-headed cowbird. | females of the brood-parasitic brown-headed cowbird (molothrus ater) search for host nests in which to lay their eggs. females normally return to lay a single egg from one to several days after first locating a potential host nest and lay up to 40 eggs in a breeding season. male brown-headed cowbirds do not assist females in locating nests. we predicted that the spatial abilities required to locate and return accurately to host nests may have produced a sex difference in the size of the hippocam ... | 1993 | 8356091 |
| contrasting histories of avian and mammalian mhc genes revealed by class ii b sequences from songbirds. | to explore the evolutionary dynamics of genes in the major histocompatibility complex (mhc) in nonmammalian vertebrates, we have amplified complete sequences of the polymorphic second (beta1) and third (beta2) exons of class ii beta chain genes of songbirds. the pattern of nucleotide substitution in the antigen-binding site of sequences cloned from three behaviorally and phylogenetically divergent songbirds [scrub jays aphelocoma coerulescens), red-winged blackbirds (agelaius phoeniceus), and ho ... | 1995 | 8618869 |
| genomics and polymorphism of agph-dab1, an mhc class ii b gene in red-winged blackbirds (agelaius phoeniceus). | to further our understanding of the evolution of avian mhc genes at the genomic level, we screened a cosmid library made from a red-winged blackbird (agelaius phoeniceus) with a blackbird cdna probe and subcloned from one of the mhc-containing cosmids a gene which we designate agph-dab1. the structure of the gene is similar to that found for chicken class ii b genes, except that the introns are surprisingly large, ranging from 98 to over 600 bp, making this the longest avian class ii b gene to d ... | 1998 | 9501491 |
| what cues do brown-headed cowbirds use to locate red-winged blackbird host nests? | i examined ecological and behavioural variables influencing the susceptibility of red-winged blackbird, agelaius phoeniceus, nests to brood parasitism by brown-headed cowbirds, molothrus ater, in a prairie-nesting population of redwings in southern wisconsin. i compared the following variables between parasitized and unparasitized nests: proximity of nests to trees and other prominent perches; physical characteristics of nests such as nest height and cover; and aspects of host behaviour, includi ... | 1998 | 9632503 |
| toward an evolutionary genomics of the avian mhc. | we review recent developments in the ongoing study of the evolution of the mhc gene family in birds, with emphasis on class ii b genes and results from songbirds obtained in our laboratory. southern blots suggest a surprising diversity in mhc class ii gene number among various songbird species (passeriformes). we have sequenced approximately 30 kb contigs from mhc bearing cosmid clones from two species, red-winged blackbirds (agelaius phoeniceus) and house finches (carpodacus mexicanus), whose d ... | 1999 | 10319255 |
| egg yolk layers vary in the concentration of steroid hormones in two avian species. | maternally derived steroid hormones are known to be present in the yolks of avian eggs; however, the physiological mechanisms involved in their deposition remain largely unexplored. investigations of steroid production by avian follicles have demonstrated temporal differences in the concentrations of progesterone, 17beta-estradiol, and testosterone during yolk formation. because yolk is deposited peripherally in concentric spheres as the oocyte develops, differences in the production of follicul ... | 1999 | 10417235 |
| determining the reproductive behaviour of individual brown-headed cowbirds using microsatellite dna markers. | the reproductive behaviour of brood-parasitic birds has been of long-standing interest to evolutionary biologists but key features such as the mating system, patterns of host use and degree of overlap of female egg-laying ranges are largely unknown for particular species. here we use microsatellite dna markers to obtain such information for one of the best-studied brood parasites, the brown-headed cowbird, molothrus ater. parentage analyses of young and adults from a marked population at delta, ... | 1999 | 10512663 |
| thyroid development in relation to the development of endothermy in the red-winged blackbird (agelaius phoeniceus). | we investigated the development of thyroid function during the transition to endothermy in red-winged blackbirds (agelaius phoeniceus). thermoregulatory capabilities of blackbirds improve markedly over their relatively short nestling period (10-12 days), with the most striking improvements occurring between days 6 and 8. we hypothesized that the development of endothermy in these birds is dependent in part on the development of thyroid function. we assessed thyroid development by measuring chang ... | 1999 | 10562450 |
| a 39-kb sequence around a blackbird mhc class ii gene: ghost of selection past and songbird genome architecture. | to gain an understanding of the evolution and genomic context of avian major histocompatibility complex (mhc) genes, we sequenced a 38.8-kb mhc-bearing cosmid insert from a red-winged blackbird (agelaius phoeniceus). the dna sequence, the longest yet retrieved from a bird other than a chicken, provides a detailed view of the process of gene duplication, divergence, and degeneration ("birth and death") in the avian mhc, as well as a glimpse into major noncoding features of a songbird genome. the ... | 2000 | 10958854 |
| improved method for quantifying the avicide 3-chloro-p-toluidine hydrochloride in bird tissues using a deuterated surrogate/gc/ms method. | a method using a deuterated surrogate of the avicide 3-chloro-p-toluidine hydrochloride (cpth) was developed to quantify the cpth residues in the gastrointestinal (gi) tract and breast muscle tissues in birds collected in cpth-baited sunflower and rice fields. this method increased the range of a previous surrogate/gas chromatography/mass spectroscopy method from 0-2 to 0-20 microg/g in tissue samples and greatly simplified the extraction procedure. the modified method also sought to increase re ... | 2002 | 11829637 |
| discrimination between host songs by brood parasitic brown-headed cowbirds ( molothrus ater). | songbirds can learn both to produce and to discriminate between different classes of acoustic stimuli. varying levels of auditory discrimination may improve the fitness of individuals in certain ecological and social contexts and, thus, selection is expected to mold the cognitive abilities of different species according to the potential benefits of acoustic processing. although fine-scale auditory discrimination of conspecific songs and calls has been frequently reported for brood parasitic brow ... | 2002 | 12357285 |
| variable effects of climate change on six species of north american birds. | many recent studies have shown that birds are advancing their laying date in response to long-term increases in spring temperatures. these studies have been conducted primarily in europe and at local scales. if climate change is a large-scale phenomenon, then we should see responses at larger scales and in other regions. we examined the effects of long-term temperature change on the laying dates and clutch sizes of six ecologically diverse species of north american birds using 50 years of nest r ... | 2005 | 16096849 |
| reduction of pore area of the avian eggshell as an adaptation to altitude. | standard measurements of water vapor conductance in units of mg of h(2)o . day(-1) . torr(-1) (si equivalent is mg of h(2)o . day(-1) . pascal(-1)) of fresh eggs of the red-winged blackbird (agelaius phoeniceus) and the native chicken of india (gallus gallus) collected at altitude are significantly less than those of eggs of the same species collected near sea level. this decrease is caused by a reduction of the total effective pore area of the eggshell at altitude. it appears to be proportional ... | 1977 | 16592423 |
| habitat edge, land management, and rates of brood parasitism in tallgrass prairie. | bird populations in north america's grasslands have declined sharply in recent decades. these declines are traceable, in large part, to habitat loss, but management of tallgrass prairie also has an impact. an indirect source of decline potentially associated with management is brood parasitism by the brown-headed cowbird (molothrus ater), which has had substantial negative impacts on many passerine hosts. using a novel application of regression trees, we analyzed an extensive five-year set of ne ... | 2006 | 16711055 |
| proximate and landscape factors influence grassland bird distributions. | ecologists increasingly recognize that birds can respond to features well beyond their normal areas of activity, but little is known about the relative importance of landscapes and proximate factors or about the scales of landscapes that influence bird distributions. we examined the influences of tree cover at both proximate and landscape scales on grassland birds, a group of birds of high conservation concern, in the sheyenne national grassland in north dakota, usa. the grassland contains a div ... | 2006 | 16827003 |
| west nile virus antibody prevalence in red-winged blackbirds (agelaius phoeniceus) from north dakota, usa (2003-2004). | this study was designed to explore the role that red-winged blackbirds (agelaius phoeniceus) may have played in disseminating west nile virus (wnv) across the united states. using enzyme-linked immunosorbent assays designed to detect wnv antibodies in avian species we were able to determine the wnv antibody prevalence in a cohort of red-winged blackbirds in central north dakota in 2003 and 2004. the peak wnv antibody prevalence was 22.0% in august of 2003 and 18.3% in july of 2004. the results o ... | 2006 | 16989570 |
| comparison of immune responses of brown-headed cowbird and related blackbirds to west nile and other mosquito-borne encephalitis viruses. | the rapid geographic spread of west nile virus (family flaviviridae, genus flavivirus, wnv) across the united states has stimulated interest in comparative host infection studies to delineate competent avian hosts critical for viral amplification. we compared the host competence of four taxonomically related blackbird species (icteridae) after experimental infection with wnv and with two endemic, mosquito-borne encephalitis viruses, western equine encephalomyelitis virus (family togaviridae, gen ... | 2007 | 17699082 |
| songbird genomics: analysis of 45 kb upstream of a polymorphic mhc class ii gene in red-winged blackbirds (agelaius phoeniceus). | here we present the sequence of a 45 kb cosmid containing a previously characterized poly-morphic mhc class ii b gene (agph-dab1) from the red-winged blackbird (agelaius phoeniceus). we compared it with a previously sequenced cosmid from this species, revealing two regions of 7.5 kb and 13.0 kb that averaged greater than 97% similarity to each another, indicating a very recent shared duplication. we found 12 retroelements, including two chicken repeat 1 (cr1) elements, constituting 6.4% of the s ... | 2001 | 11472064 |
| the liver parenchyma and foreign compound metabolism in red-winged blackbird compared with rat. | 1. aniline p-hydroxylase, aminopyrine n-demethylase, and p-nitroanisole o-demethylase activities were measured in liver microsomes prepared from the red-winged blackbird (agelaius phoeniceus) and compared with analogous preparations from rat. all had lower activities in birds than in rats, when expressed in terms of microsomal protein. 2. hepatic parenchyma of the bird was observed by electron microscopy to contain less endoplasmic reticulum than that of rat. this morphological difference may pa ... | 1975 | 1154795 |
| realized reproductive success of polygynous red-winged blackbirds revealed by dna markers. | hypervariable genetic markers, including a novel locus-specific marker detected by a mouse major histocompatibility complex probe, reveal that multiple paternity is common in families of polygynous red-winged blackbirds (agelaius phoeniceus). almost half of all nests contained at least one chick resulting from an extra-pair fertilization, usually by a neighboring male. genetically based measures of reproductive success show that individual males realize more than 20% of their overall success fro ... | 1990 | 17754986 |
| an mhc component to kin recognition and mate choice in birds: predictions, progress, and prospects. | the major histocompatibility complex (mhc) has been identified as a locus influencing disease resistance, mate choice, and kin recognition in mammals and fish. however, it is unclear whether the mechanisms by which mhc genes influence behavior in mammals are applicable to other nonmammalian vertebrates such as birds. we review the biology of mhc genes with particular reference to their relevance to avian mating and social systems. new genomics approaches recently have been applied to the mhcs of ... | 2002 | 18707479 |
| dispersal of viable row-crop seeds of commercial agriculture by farmland birds: implication for genetically modified crops. | to address some concerns about the expansion of genetically engineered pharmaceutical and industrial crops to outdoor plantings and potential impacts on the human food supply, we determined whether commercial agriculture seeds of maize or corn zea mays l., barley hordeum vulgare l., safflower carthamus tinctorius l. and rice oryza sativa l. are digested or pass viably through the digestive tract, or are transported externally, by captive mallard ducks anas platyrhynchos l., ring-necked pheasants ... | 2008 | 19081011 |
| 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 |
| permanent genetic resources added to molecular ecology resources database 1 june 2011-31 july 2011. | this article documents the addition of 112 microsatellite marker loci and 24 pairs of single nucleotide polymorphism (snp) sequencing primers to the molecular ecology resources database. loci were developed for the following species: agelaius phoeniceus, austrolittorina cincta, circus cyaneus, circus macrourus, circus pygargus, cryptocoryne × purpurea ridl. nothovar. purpurea, mya arenaria, patagioenas squamosa, prochilodus mariae, scylla serrata and scytalopus speluncae. these loci were cross-t ... | 2011 | 21951598 |
| immune function in an avian brood parasite and its nonparasitic relative. | organisms that breed multiple times must trade off resources between current and future reproduction. in many species, sexual selection can lead to reduced levels of immune function in males because they invest heavily in current reproduction at the expense of self-maintenance. much less is known about whether the same trend is seen in species such as the brood-parasitic brown-headed cowbird molothrus ater (hereafter "cowbird"), in which females invest heavily in current reproduction. we examine ... | 2012 | 23303321 |
| song-related brain regions in the red-winged blackbird are affected by sex and season but not repertoire size. | previous work in songbirds has delimited a neural system responsible for song production and control. earlier studies have suggested that functional capacity in the song system may be related to the mass of the system in an animal's brain, and that adult plasticity in this neural system may be related to adult capacity for behavioral modification. we now test these hypotheses in adult red-winged blackbirds (agelaius phoeniceus), a species in which song is produced primarily by males, new song ty ... | 2009 | 2708980 |
| a study of the helminth parasites of overwintering red-winged blackbirds (agelaius phoeniceus) from laurel, maryland. | | 2015 | 4436770 |
| effects of acoustical stimulation and deprivation on song development in red-winged blackbirds (agelaius phoeniceus). | | 2015 | 4661310 |
| cryptosporidium galli and novel cryptosporidium avian genotype vi in north american red-winged blackbirds (agelaius phoeniceus). | proventriculus and intestinal samples from 70 north american red-winged blackbirds (agelaius phoeniceus; order passeriformes) were examined for the presence of cryptosporidium by pcr amplification and sequence analysis of the 18s ribosomal rna (18s rrna), actin, and 70-kda heat shock protein (hsp70) genes. twelve birds (17.1 %) were positive for the cryptosporidium 18s rrna gene: six birds were positive at the proventriculus site only and six birds were positive at the proventriculus and intesti ... | 2016 | 26818945 |
| cascade of ecological consequences for west nile virus transmission when aquatic macrophytes invade stormwater habitats. | artificial aquatic habitats are ubiquitous in anthropogenic landscapes and highly susceptible to colonization by invasive plant species. recent research into the ecology of infectious diseases indicates that the establishment of invasive plant species can trigger ecological cascades which alter the transmission dynamics of vector-borne pathogens that imperil human health. here, we examined whether the presence or management of two invasive, emergent plants, cattails (typha spp.) and phragmites ( ... | 2016 | 27039521 |
| enhanced innate immune responses in a brood parasitic cowbird species: degranulation and oxidative burst. | we examined the relative effectiveness of two innate immune responses in two species of new world blackbirds (passeriformes, icteridae) that differ in resistance to west nile virus (wnv). we measured degranulation and oxidative burst, two fundamental components of phagocytosis, and we predicted that the functional effectiveness of these innate immune responses would correspond to the species' relative resistance to wnv. the brown-headed cowbird (molothrus ater), an obligate brood parasite, had p ... | 2013 | 24689187 |
| why do caterpillars whistle at birds? insect defence sounds startle avian predators. | many insects produce sounds when attacked by a predator, yet the functions of these signals are poorly understood. it is debated whether such sounds function as startle, warning or alarm signals, or merely serve to augment other defences. direct evidence is limited owing to difficulties in disentangling the effects of sounds from other defences that often occur simultaneously in live insects. we conducted an experiment to test whether an insect sound can function as a deimatic (i.e. startle) dis ... | 2017 | 28232054 |
| red-winged blackbirds (agelaius phoeniceus) with higher baseline glucocorticoids also invest less in incubation and clutch mass. | glucocorticoid hormones facilitate responses to environmental challenges by mediating diverse physiological and behavioral changes, including resource mobilization and altered reproductive effort. elevated glucocorticoids might indicate that an individual is facing high levels of environmental challenges and thus, elevated concentrations might be associated with reduced fitness (cort-fitness hypothesis). alternatively, the energetic demands of reproduction might be a challenge that requires elev ... | 2017 | 28189642 |
| nest sanitation does not elicit egg ejection in a brown-headed cowbird host. | most passerine birds practice nest sanitation whereby they remove debris from their nest. nest sanitation has been posited as a pre-adaptation for egg ejection by hosts of avian brood parasites. however, relatively few north american hosts of the brood parasitic brown-headed cowbird (molothrus ater) eject cowbird eggs to the detriment of their fitness. in this study, i added either a piece of flagging tape or a pine cone bract scale along with an artificial cowbird egg to nests of the red-winged ... | 2017 | 27858167 |
| multi-isotopic (δ2h, δ13c, δ15n) tracing of molt origin for red-winged blackbirds associated with agro-ecosystems. | we analyzed stable-hydrogen (δ2h), carbon (δ13c) and nitrogen (δ 15n) isotope ratios in feathers to better understand the molt origin and food habits of red-winged blackbirds (agelaius phoeniceus) near sunflower production in the upper midwest and rice production in the mid-south of the united states. outer primary feathers were used from 661 after-second-year (asy) male blackbirds collected in minnesota, montana, north dakota and south dakota (spring collection), and arkansas, louisiana, missis ... | 2016 | 27846302 |
| breathing while altricial: the ontogeny of ventilatory chemosensitivity in red-winged blackbird (agelaius phoeniceus) nestlings. | altricial bird species, like red-winged blackbirds, hatch at an immature state of functional maturity with limited aerobic capacity and no endothermic capacity. over the next 10-12 days in the nest, red-winged blackbirds develop increased metabolic capacity before fledging. although ontogeny of respiration has been described in precocial birds, ontogeny of ventilatory chemosensitivity is unknown in altricial species. here we examined developmental changes in chemosensitivity of tidal volume (vt) ... | 2016 | 27707721 |
| sex and seasonal differences in hippocampal volume and neurogenesis in brood-parasitic brown-headed cowbirds (molothrus ater). | brown-headed cowbirds (molothrus ater) are one of few species in which females show more complex space use than males. female cowbirds search for, revisit, and parasitize host nests and, in a previous study, outperformed males on an open field spatial search task. previous research reported a female-biased sex difference in the volume of the hippocampus, a region of the brain involved in spatial memory. neurons produced by adult neurogenesis may be involved in the formation of new memories and r ... | 2016 | 27455512 |
| the 12-day thermoregulatory metamorphosis of red-winged blackbirds (agelaius phoeniceus). | we examined development of endothermy in altricial red-winged blackbirds (agelaius phoeniceus) by measuring oxygen consumption [formula: see text], body temperature and ventilation at ambient temperatures from 35 to 15 °c. mitochondrial respiration of permeabilized skeletal muscle was also measured from breast (pectoralis) and thigh (femorotibialis) muscles. animals were studied from the first day of hatching through fledging (12 days post-hatch, dph). nestling whole-body metabolic rate began to ... | 2016 | 27003423 |
| sex and seasonal differences in neurogenesis and volume of the song-control system are associated with song in brood-parasitic and non-brood-parasitic icterid songbirds. | the song-control system in the brain of songbirds is important for the production and acquisition of song and exhibits both remarkable seasonal plasticity and some of the largest neural sex differences observed in vertebrates. we measured sex and seasonal differences in two nuclei of the song-control system of brood-parasitic brown-headed cowbirds (molothrus ater) and closely-related non-parasitic red-winged blackbirds (agelaius phoeniceus). these species differ in both the development and funct ... | 2016 | 26898912 |
| mercury concentrations in eggs of red-winged blackbirds and tree swallows breeding in voyageurs national park, minnesota. | most investigations of the environmental effects of mercury (hg) have focused on aquatic food webs that include piscivorous fish or wildlife. however, recent investigations have shown that other species, including passerine songbirds, may also be at risk from exposure to methylmercury (mehg). we quantified hg concentrations in eggs of two species of songbirds, red-winged blackbirds (agelaius phoeniceus) and tree swallows (tachycineta bicolor), nesting in voyageurs national park, minnesota, usa. ... | 2016 | 26801652 |
| a review of the mite subfamily harpirhynchinae (acariformes: harpirhynchidae)--parasites of new world birds (aves: neognathae). | mites of the subfamily harpirhynchinae (acariformes: cheyletoidea: harpirhynchidae) associated with neognathous birds (aves: neognathae) in the new world are revised. in all, 68 species in 8 genera are recorded. among them, 27 new species and 1 new genus are described as new for science: harpyrhynchoides gallowayi bochkov, oconnor and klompen sp. nov. from columba livia (columbiformes: columbidae) from canada (manitoba), h. zenaida bochkov, oconnor and klompen sp. nov. from zenaida macroura (col ... | 2015 | 26624161 |
| 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 ... | 2015 | 26287671 |
| genetic diversity does not explain variation in extra-pair paternity in multiple populations of a songbird. | many songbirds are socially monogamous but genetically polyandrous, mating with individuals outside their pair bonds. extra-pair paternity (epp) varies within and across species, but reasons for this variation remain unclear. one possible source of variation is population genetic diversity, which has been shown in interspecific meta-analyses to correlate with epp but which has limited support from intraspecific tests. using eight populations of the genetically polyandrous red-winged blackbird (a ... | 2015 | 25876793 |
| epaulet size and current condition in red-winged blackbirds: examining a semistatic signal, testosterone, immune function, and parasites. | some sexually selected signals are thought to convey information about the current condition and genetic/epigenetic quality of the individual signaling, including the ability to resist parasites. however, it is unclear whether semistatic sexual signals that develop periodically and remain stable over protracted periods, such as avian breeding plumage, can relate to measures of current condition and health. we examined a semistatic signal (wing epaulet size) in male red-winged blackbirds (agelaiu ... | 2015 | 25590590 |
| fire, humans, and climate: modeling distribution dynamics of boreal forest waterbirds. | understanding the effects of landscape change and environmental variability on ecological processes is important for evaluating resource management policies, such as the emulation of natural forest disturbances. we analyzed time series of detection/nondetection data using hierarchical models in a bayesian multi-model inference framework to decompose the dynamics of species distributions into responses to environmental variability, spatial variation in habitat conditions, and population dynamics ... | 2014 | 24640539 |
| histoplasmosis associated with a bamboo bonfire--arkansas, october 2011. | on october 27, 2011, the arkansas department of health (adh) was notified by a northeast arkansas primary care provider of a cluster of three histoplasmosis cases. on november 4, adh was notified by a pediatric infectious diseases specialist regarding seven potential cases of pulmonary histoplasmosis associated with a family gathering that included a bonfire that burned bamboo from a grove that had been a red-winged blackbird roost. these reports prompted an outbreak investigation to ensure that ... | 2014 | 24572611 |
| mercury exposure of a wetland songbird, agelaius phoeniceus, in the new york metropolitan area and its effect on nestling growth rate. | the potential for mercury accumulation in free-living passerine birds is now recognized to be much greater than previously assumed. however, lowest observable effect levels have yet to be well established for this taxonomic group and it is usually unknown whether levels observed in the wild are causing adverse effects. we measured total blood mercury (thg) levels and took repeated morphological measurements from nestling red-winged blackbirds (agelaius phoeniceus; n = 39) in the new york metropo ... | 2014 | 24526618 |
| range dynamics, rather than convergent selection, explain the mosaic distribution of red-winged blackbird phenotypes. | geographic distributions of genetic and phenotypic characters can illuminate historical evolutionary processes. in particular, mosaic distributions of phenotypically similar populations can arise from parallel evolution or from irregular patterns of dispersal and colonization by divergent forms. two phenotypically divergent forms of the red-winged blackbird (agelaius phoeniceus) show a mosaic phenotypic distribution, with a "bicolored" form occurring disjunctly in california and mexico. we analy ... | 2013 | 24455125 |
| contrasting evolutionary dynamics and information content of the avian mitochondrial control region and nd2 gene. | mitochondrial dna is an important tool for inference of population history in animals. a variety of mitochondrial loci have been sampled for this purpose, but many studies focus on the non-coding d-loop or control region (cr), which in at least some species appears hypermutable. unfortunately, analyses of this region are sometimes complicated by segmental duplications, as well as by difficulties in sequencing through repeat expansions, driving many researchers to favor single-copy protein-coding ... | 2012 | 23071562 |
| the role of a generalized ultraviolet cue for blackbird food selection. | birds utilize ultraviolet (uv) wavelengths for plumage signaling and sexual selection. ultraviolet cues may also be used for the process of avian food selection. the aim of our study was to investigate whether a uv cue and a postingestive repellent can be used to condition food avoidance in red-winged blackbirds (agelaius phoeniceus). we found that birds conditioned with an uv-absorbent, postingestive repellent subsequently avoided uv-absorbent food. thus, the uv-absorbent cue (coupled with 0-20 ... | 2012 | 22525492 |
| anthropogenic noise affects song structure in red-winged blackbirds (agelaius phoeniceus). | anthropogenic noise can mask animal signals that are crucial for communicating information about food, predators and mating opportunities. in response to noise masking, signallers can potentially improve acoustic signal transmission by adjusting the timing, frequency or amplitude of their signals. these changes can be a short-term modification in response to transient noise or a long-term modification in response to chronic noise. an animal's ability to adapt to anthropogenic noise can be crucia ... | 2011 | 21993783 |
| reconciling sensory cues and varied consequences of avian repellents. | we learned previously that red-winged blackbirds (agelaius phoeniceus) use affective processes to shift flavor preference, and cognitive associations (colors) to avoid food, subsequent to avoidance conditioning. we conducted three experiments with captive red-winged blackbirds to reconcile varied consequences of treated food with conditioned sensory cues. in experiment 1, we compared food avoidance conditioned with lithium chloride (licl) or naloxone hydrochloride (nhcl) to evaluate cue-conseque ... | 2011 | 20971129 |
| egg size and asymmetric sibling rivalry in red-winged blackbirds. | how big to make an egg is a life history decision that in birds is made coincident with a series of other similar decisions (how many eggs to have, whether to fortify them with maternally derived hormones or immune system boosters, whether to hatch the eggs synchronously or asynchronously). though within-population variation in egg size in birds has been well studied, its adaptive significance, if any, is unclear. here we examine within-population variation in egg size in relation to asymmetric ... | 2010 | 20401493 |
| acute oral toxicities of wildland fire control chemicals to birds. | wildland fire control chemicals are released into the environment by aerial and ground applications to manage rangeland, grassland, and forest fires. acute oral 24h median lethal dosages (ld50) for three fire retardants (fire-trol gts-r, phos-chek d-75f, and fire-trol lcg-r) and two class a fire suppressant foams (silv-ex and phos-chek wd881) were estimated for northern bobwhites, colinus virginianus, american kestrels, falco sparverius, and red-winged blackbirds, agelaius phoeniceus. the ld50s ... | 2009 | 19038451 |
| cross-protection between west nile and japanese encephalitis viruses in red-winged blackbirds (agelaius phoeniceus). | similar to west nile virus (wnv), japanese encephalitis virus (jev) has a history of intercontinental spread, and birds are important for the maintenance and transmission of both of these closely related viruses. we examined viremic and serologic responses of blackbirds (agelaius phoeniceus), with and without immunity to wnv, following experimental inoculation with two strains of jev. japanese encephalitis (je) viremia was detected in only one of 16 (6.3%) wnv-immune birds, while all 16 nonimmun ... | 2009 | 19848083 |
| further investigations of the mite genus syringophiloidus kethley, 1970 (acariformes: syringophilidae) from north american passerines. | four new syringophilid species of syringophiloidus kethley, 1970 are described from north american passerines: s. zonotrichia n. sp. from zonotrichia albicolis (gmelin) (emberizidae) on texas; s. jackowiaki n. sp. from poecile carolinensis (auduborn) (paridae) in texas; and s. xanthocephalus n. sp. from xanthocephalus xanthocephalus (bonaparte) (icteridae) and s. agelaius n. sp. from agelaius phoeniceus linnaeus (icteridae), both from arizona. spizella breweri (cassin) (emberizidae) from califor ... | 2011 | 21643897 |
| lead, mercury, cadmium, chromium, and arsenic levels in eggs, feathers, and tissues of canada geese of the new jersey meadowlands. | the new jersey meadowlands are located within the heavily urbanized new york/new jersey harbor estuary and have been subject to contamination due to effluent and runoff from industry, traffic, and homes along the hackensack river and nearby waterways. these extensive wetlands, though heavily impacted by development and pollution, support a wide array of bird and other wildlife species. persistent contaminants may pose threats to birds in these habitats, affecting reproduction, egg hatchability, ... | 2011 | 21679937 |
| metal concentrations in three species of passerine birds breeding in the hackensack meadowlands of new jersey. | the new jersey meadowlands is an important natural area, a diverse mosaic of wetland habitats positioned within the heavily urbanized ny city metropolitan area and the ny/nj harbor. persistent contaminants may pose threats to wildlife inhabiting these habitats, affecting reproduction, egg hatchability, nestling survivorship, and neurobehavioral development. metals of concern in the meadowlands include arsenic, cadmium, chromium, lead, and mercury. these metals were analyzed in feathers and blood ... | 2008 | 18191831 |
| non-linear uptake and hormesis effects of selenium in red-winged blackbirds (agelaius phoeniceus). | effects of selenium on reproductive success were assessed in red-winged blackbirds (agelaius phoeniceus). mean egg selenium (mes) ranged from 2.96 to 21.7 mg/kg dry weight with individual eggs up to 40 mg/kg. uptake was non-linear: increments in mes declined as aqueous selenium increased; the asymptote was approximately 23 mg/kg. eggs were heavier and more were laid in 2004 compared to 2005, a year of record rainfall and below-normal temperatures. mortality of embryos that were incubated to full ... | 2008 | 17963820 |
| food color, flavor, and conditioned avoidance among red-winged blackbirds. | the relationship between food flavors and postingestive feedback enables mammalian herbivores to procure nutrients and avoid toxins within ever-changing environments. we conducted four experiments with red-winged blackbirds (agelaius phoeniceus) in captivity to determine the relative roles of color and flavor cues paired with negative postingestive feedback. we first conducted baseline tests to assess preferences for colors and flavors. all blackbirds preferred red- to blue-colored food, and the ... | 2008 | 17804026 |
| effects of phos-chek g75-f and silv-ex on red-winged blackbird (agelaius phoeniceus) embryos. | effects of field application levels of wildfire control chemicals, phos-chek g75-f (pc) and silv-ex (se), were examined on red-winged blackbird (agelaius phoeniceus) embryos. embryos were more sensitive to pc and se when eggs were immersed for 10s at an early developmental stage (days 3-5 of incubation) than at a later stage (days 6-9 of incubation). the lc(50) (concentration causing 50% mortality) for early stage embryos exposed to pc was 213.3g/l (slope=1.6; 95% confidence interval [ci]=129.1- ... | 2007 | 17223235 |
| 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 ... | 2006 | 16519318 |
| 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 ... | 2006 | 16317482 |
| long-term decline in a red-winged blackbird population: ecological causes and sexual selection consequences. | habitat loss and large-scale climate phenomena are widely implicated as causing decline in animal populations. i examined how both factors contributed to a precipitous decline in an ontario red-winged blackbird (agelaius phoeniceus) population using 16 years of data collected between 1974 and 1995. the decline was manifested as an almost 50% reduction in mean harem size, which reduced the opportunity for sexual selection threefold. regional hay production, which should affect recruitment into th ... | 2005 | 16191645 |
| tests of spatial and temporal factors influencing extra-pair paternity in red-winged blackbirds. | extra-pair paternity (epp) is a widespread and highly variable reproductive phenomenon in birds. we tested the effects of habitat, spatial factors, and timing of breeding on the occurrence of epp in red-winged blackbirds (agelaius phoeniceus). we used pcr-amplified microsatellites to assess the paternity of 1479 nestlings from 537 broods on 235 territories over four breeding seasons. over 4 years, 40% of nestlings were extra-pair. at least 27% of actual sires were non-neighbours, suggesting that ... | 2005 | 15910334 |
| effects of climate variation on timing of nesting, reproductive success, and offspring sex ratios of red-winged blackbirds. | predicting ecological consequences of climate change will be improved by understanding how species are affected by contemporary climate variation, particularly if analyses involve more than single ecological variables and focus on large-scale climate phenomena. i used 18 years of data from red-winged blackbirds (agelaius phoeniceus) studied over a 25-year period in eastern ontario to explore chronological and climate-related patterns of reproduction. although blackbirds started nesting earlier i ... | 2005 | 15891814 |
| hitchhiking and recombination in birds: evidence from mhc-linked and unlinked loci in red-winged blackbirds (agelaius phoeniceus). | hitchhiking phenomena and genetic recombination have important consequences for a variety of fields for which birds are model species, yet we know virtually nothing about naturally occurring rates of recombination or the extent of linkage disequilibrium in birds. we took advantage of a previously sequenced cosmid clone from red-winged blackbirds (agelaius phoeniceus) bearing a highly polymorphic mhc class ii gene, agph-dabi, to measure the extent of linkage disequilibrium across approximately 40 ... | 2004 | 15822606 |
| absorption, distribution, and excretion of [14c]-3-chloro-4-methylaniline hydrochloride in two species of birds following a single oral dose. | ring-labeled [14c]-3-chloro-4-methylaniline hydrochloride (250 microg per bird) was delivered to 21 red-winged blackbirds (agelaius phoeniceus) and 21 dark-eyed juncos (junco hyemalis) via oral gavage, and the distribution and excretion of radioactivity were determined at 15 and 30 min and 1, 4, 8, 12, and 24 h (n = 3 per time point). direct measurement of radioactivity as well as measurement following combustion was accomplished using a liquid scintillation counter. elimination from most tissue ... | 2004 | 15612798 |
| contaminant exposure and effects in red-winged blackbirds inhabiting stormwater retention ponds. | stormwater wetlands are created to retain water from storms and snow melt to reduce sediment, nutrient, and contaminant pollution of natural waterways in metropolitan areas. however, they are often a source of attractive habitat to wetland-associated wildlife. in this study of 12 stormwater wetlands and a larger, older reference site, elevated concentrations of zinc and copper were found in sediments and carcasses of 8-day-old red-winged blackbird (agelaius phoeniceus) nestlings inhabiting storm ... | 2004 | 15503389 |
| male red-winged blackbirds distrust unreliable and sexually attractive neighbours. | in many species, territorial neighbours fight to establish their mutual border and then develop a truce, known as the dear-enemy phenomenon, characterized by reduced vigilance and aggression along the border. we present evidence that among male red-winged blackbirds (agelaius phoeniceus) the dear-enemy relationship is a form of reciprocal conditional cooperation that is stabilized, at least in part, by retaliation against cheaters. simulated intrusions by randomly chosen neighbours were punished ... | 2004 | 15293856 |
| microsatellite variation in red-winged blackbirds (agelaius phoeniceus). | territorial male red-winged blackbirds from five locations in the united states and canada were genotyped using a suite of six microsatellite loci. each population possessed unique alleles, but numbers of alleles per locus (range = 7.3-8.8) and expected multilocus heterozygosities (range = 0.76-0.80) were similar in all populations. significant overall allele frequency differences were detected between some population pairs, and some pairwise fst values were significant (but small). however, fst ... | 2004 | 15068337 |
| cooperative nest defence in red-winged blackbirds: reciprocal altruism, kinship or by-product mutualism? | male red-winged blackbirds (agelaius phoeniceus) often cooperate with their neighbours in defending nests against predators. some studies have suggested that this is an example of by-product mutualism, whereas others have suggested the possibility of reciprocal altruism. no study has addressed the possibility of kin-selected cooperation in nest defence in this species. reciprocal altruism, kin selection and by-product mutualism are not mutually exclusive alternatives, but few studies of territor ... | 2004 | 15058395 |
| sexual size dimorphism and timing of spring migration in birds. | sexually selected traits are limited by selection against those traits in other fitness components, such as survival. thus, sexual selection favouring large size in males should be balanced by higher mortality of larger males. however, evidence from red-winged blackbirds (agelaius phoeniceus) indicates that large males survive better than small males. a survival advantage to large size could result from males migrating north in early spring, when harsh weather favours large size for energetic re ... | 2003 | 14635890 |
| effects of the mosquito larvicide gb-1111 on red-winged blackbird embryos. | golden bear oil (gb-1111; legal trade name for gb-1313) is a petroleum distillate that is used in the united states and other countries as a larvicide for mosquito suppression. as part of a multi-species evaluation of the potential effects of gb-1111 on birds, red-winged blackbird eggs were collected, artificially incubated, and treated with one of five amounts of gb-1111 varying from 0 to 10 times the expected exposure from a spray application of the maximum recommended amount (x=47 l/ha, 5 gal ... | 2003 | 12826422 |
| selenium in a wyoming grassland community receiving wastewater from an in situ uranium mine. | water, soil, vegetation, grasshoppers, bird eggs, and bird livers collected at a 23.5-ha (58 acres) grassland irrigated with wastewater from an in situ uranium mine (study area) and a reference site in 1998 were analyzed for selenium and other trace elements. selenium concentrations in the uranium mine wastewater applied onto the grassland ranged from 340 to 450 microg/l. selenium in the upper 15 cm (6 in) of soil from the irrigated grassland at the mine ranged from 2.6 to 4.2 microg/g dry weigh ... | 2002 | 11994784 |
| ontogeny of catabolic and morphological properties of skeletal muscle of the red-winged blackbird (agelaius phoeniceus). | thermogenic capabilities of red-winged blackbirds improve markedly during their 10-12-day nestling period, especially between day 5 and day 8. the time course of improvements may be determined by the maturation of skeletal muscles involved in shivering thermogenesis, particularly the pectoralis muscles. to test this hypothesis, morphological and biochemical changes in pectoral and leg muscles were measured in young and adult blackbirds. both muscles grew disproportionately relative to body mass. ... | 2001 | 11686611 |
| experimental confirmation of the polygyny threshold model for red-winged blackbirds. | the polygyny threshold model assumes that polygynous mating is costly to females and proposes that females pay the cost of polygyny only when compensated by obtaining a superior territory or male. we present, to the authors' knowledge, the first experimental field test to demonstrate that females trade mating status against territory quality as proposed by this hypothesis. previous work has shown that female red-winged blackbirds (agelaius phoeniceus) in ontario prefer settling with unmated male ... | 2001 | 11487413 |
| maternally derived yolk testosterone enhances the development of the hatching muscle in the red-winged blackbird agelaius phoeniceus. | hatching asynchrony in avian species often leads to the formation of a size hierarchy that places last-hatched nestlings at a significant disadvantage. the hatching muscle (musculus complexus) is responsible for breaking the shell during hatching and for dorsal flexion of the neck during begging. an increase in its strength in last-hatched nestlings could mitigate the effects of hatching asynchrony by reducing the time required for hatching or enhancing the effectiveness of begging for parentall ... | 2000 | 11075714 |
| division of labour in colony defence against vertebrate predators by the social wasp polistes fuscatus. | in this study i examined how the paper wasp, polistes fuscatus, defends a colony when faced with a vertebrate attack. i looked for a division of labour in defensive behaviour within a colony and examined whether this behaviour changes over the colony cycle. the colonies were presented with a model of an adult red-winged blackbird, agelaius phoeniceus, and a speaker that vibrated the comb. there was a pronounced division of labour in the defence against vertebrate predators within a colony. the q ... | 2000 | 10924203 |
| polymorphism across an exon-intron boundary in an avian mhc class ii b gene. | twenty-three sequence haplotypes spanning the boundary of the second exon and intron of a red-winged blackbird mhc class ii b gene, agph-dab1, are presented. the polymorphism of the exon segment is distributed in two divergent allelic lineages which appear to be maintained by balancing selection. the silent nucleotide diversity of the exon (pi = 0.101) is more than five times that of the intron (pi = 0.018) and decays rapidly across the exon-intron boundary. additionally, genealogical reconstruc ... | 1999 | 10555291 |
| locating animals from their sounds and tomography of the atmosphere: experimental demonstration. | calling animals are located using widely distributed receivers, and the sounds from the animals are used to map the sound speed and wind fields by means of tomography. in particular, two red-winged blackbirds agelaius phoeniceus are correctly located within a meter using recordings from five receivers spread over a 20 by 30 m region. the demonstration hinges on two new developments. first, a new algorithm for blindly estimating the impulse response of the channel is shown capable of estimating t ... | 1999 | 10462789 |
| red-winged blackbird females fail to increase feeding in response to begging call playbacks. | the begging behaviour of nestling birds appears to be the main signal telling parents how much food is needed by the brood. not only may the accuracy of that information be reduced through exaggeration due to competition, but it may also vary with the age of the nestling. younger nestlings may vary more in how frequently they call than older nestlings because they cannot discriminate stimuli as well. thus, even if 'honest', begging from younger nestlings could be a less reliable hunger signal th ... | 1998 | 9784204 |
| response to playback of nestling begging in the red-winged blackbird, agelaius phoeniceus. | nestling birds may honestly signal their need for food to provisioning adults, or begging might be a manipulative attempt to coerce additional food from providers, but in either case, providers respond to an increase in begging with an increase in feeding. we used playback of begging calls recorded from nestlings to determine whether male and female red-winged blackbirds increase their feeding rates in response to an apparent increase in begging. both females and males fed broods at significantl ... | 1998 | 9784203 |
| behavioural correlates of testosterone and seasonal changes of steroids in red-winged blackbirds. | i studied the relationship between behaviour and plasma testosterone level (t) and the seasonal changes in t and plasma corticosterone levels (b) in male red-winged blackbirds, agelaius phoeniceus. i measured t and b using radioimmunoassay, and on the day after taking blood, i observed each male's behaviour for 60 min. the time that males spent conspicuously perched and the number of songs were positively correlated with t, but the proportion of time spent conspicuously perched and the frequency ... | 1998 | 9632481 |
| lipid and water depletion in migrating passerines following passage over the gulf of mexico. | lipid depletion is currently believed to be the primary factor limiting flight duration of migrating birds in north america, while the influence of water loss is thought to be small. three migrating species of passerines, wood thrush (hylocichla mustelina), swainson's thrush (catharus ustulatus), and summer tanager (piranga rubra) were captured during the 1993 spring migration just after crossing the gulf of mexico and examined for lipid and water depletion. the redwinged blackbird (agelaius pho ... | 1996 | 28307151 |
| characterization of the reflective materials and organelles in the bright irides of north american blackbirds (icterinae). | the reflective materials in the iris stroma of bright-irised american blackbirds (icterinae, emberizidae) and the red-eyed vireo (vireo olivaceus) (vireonidae) were characterized using high-performance liquid chromatography (hplc) and diode-array detection. two purines, guanine and hypoxanthine, and two pteridines, leucopterin and xanthopterin, were detected in large amounts in all bright irides. the brown iris of the red-winged blackbird (agelaius phoeniceus) by comparison contained only small ... | 1996 | 8857673 |
| mortality of passerines adjacent to a north carolina corn field treated with granular carbofuran. | red-winged blackbirds (agelaius phoeniceus) were collected during an epizootic in southeastern north carolina (usa). activity of brain cholinesterase (che) was inhibited by 14 to 48% in three of five specimens, and returned to normal levels after incubation. gastrointestinal tracts were analyzed for 30 anti-che agents. carbofuran, the only compound detected, was present in all specimens at levels from 5.44 to 72.7 micrograms/g wet weight. application of granular carbofuran in an adjacent corn fi ... | 1996 | 8627921 |
| the ontogeny of shivering thermogenesis in the red-winged blackbird (agelaius phoeniceus) | the ontogeny of shivering thermogenesis was investigated in the altricial red-winged blackbird (agelaius phoeniceus). two indices of heat production ­ the rate of oxygen consumption (v(dot)o2) of the bird and the electromyographic (emg) activity of the pectoralis (pect) and gastrocnemius (gast) muscles ­ were measured simultaneously in adult and nestling red-winged blackbirds as they were subjected first to thermoneutral temperatures and subsequently to progressively colder ambient tempe ... | 1994 | 9317339 |
| year-to-year patterns of circulating levels of testosterone and corticosterone in relation to breeding density, experience, and reproductive success of the polygynous red-winged blackbird. | to determine across-year patterns in plasma testosterone (t) and corticosterone (b) levels in free-living birds, we took blood samples in the same 2-week breeding period during 4 consecutive years from territorial male red-winged blackbirds. we used our data to test predictions of the "challenge hypothesis" of t secretion and also to examine hormonal correlations with age, breeding experience, breeding density, and reproductive success. average t and b levels across years were not significantly ... | 1992 | 1398560 |