| enteritis as a cause of mortality in the western bluebird (sialia mexicana). | increased mortalities in adult western bluebirds utilizing nestboxes were noted in western oregon during 1998 and 1999. a necrohemorrhagic enteritis was found in 8 of 10 birds submitted for necropsy. acanthocephalan parasites were present in four of eight birds with enteritis. microscopic changes consistent with necrotic or ulcerative enteritis were commonly present. anaerobic culture of the intestine yielded clostridium perfringens in three of three birds. genotype analysis of two of these isol ... | 2001 | 11569757 |
| the ecological and physiological costs of lead shot and immunological challenge to developing western bluebirds. | we investigated the interacting effects of a nonpathogenic immunological challenge and exposure to lead shot early in the development of nestling western bluebirds (sialia mexicana). nestlings were randomly assigned to each of six treatments of an incomplete block design with two antigen treatments, newcastle disease virus (ndv) or sheep red blood cells (srbc), and four lead shot treatments (no shot, one shot--0.05 g, 2 shots--0.1 g, or three shots--0.15 g). survival functions did not differ bet ... | 2002 | 12092753 |
| quill mites of the genus syringophilopsis kethley, 1970 (acari: syringophilidae) from north american birds. | seven mite species belonging to the genus syringophilopsis kethley, 1970 (acari: prostigmata: cheyletoidea) are recorded from 10 passeriform host species from the usa. three new species are described and illustrated: syringophilopsis polioptilus sp. n. from polioptila caerulea (linnaeus) (polioptilidae); s. empidonax sp. n. from empidonax hamrnmondii (vesey) and empidonax wrightii baird (tyrannidae); and s. sialiae sp. n. from sialia mexicana swainson (turdidae). in addition, records of new host ... | 2008 | 19175207 |
| quantifying the multi-scale response of avifauna to prescribed fire experiments in the southwest united states. | landscape-scale disturbance events, including ecological restoration and fuel reduction activities, can modify habitat and affect relationships between species and their environment. to reduce the risk of uncharacteristic stand-replacing fires in the southwestern united states, land managers are implementing restoration and fuels treatments (e.g., mechanical thinning, prescribed fire) in progressively larger stands of dry, lower elevation ponderosa pine (pinus ponderosa) forest. we used a before ... | 2009 | 19425425 |
| avian conservation practices strengthen ecosystem services in california vineyards. | insectivorous western bluebirds (sialia mexicana) occupy vineyard nest boxes established by california winegrape growers who want to encourage avian conservation. experimentally, the provision of available nest sites serves as an alternative to exclosure methods for isolating the potential ecosystem services provided by foraging birds. we compared the abundance and species richness of avian foragers and removal rates of sentinel prey in treatments with songbird nest boxes and controls without ne ... | 2011 | 22096555 |
| bacteria-killing ability of fresh blood plasma compared to frozen blood plasma. | in recent years, the bacteria-killing assay (bka) has become a popular technique among ecoimmunologists. new variations of that assay allow researchers to use smaller volumes of blood, an important consideration for those working on small-bodied animals. however, this version of the assay requires access to a lab with a nanodrop spectrophotometer, something that may not be available in the field. one possible solution is to freeze plasma for transport; however, this assumes that frozen plasma sa ... | 2016 | 26456418 |
| early reproductive success of western bluebirds and ash-throated flycatchers: a landscape-contaminant perspective. | eggshell quality, clutch size, sex ratio, and hatching success of western bluebirds (sialia mexicana) and ash-throated flycatchers (myiarchus cinerascens) were studied on a landscape-soil contaminant gradient at los alamos national laboratory (lanl) in new mexico from 1997 to 1999. a variety of contaminants (heavy metals, chemicals, insecticides, polychlorinated biphenyls (pcbs), organochlorines, and radioactive isotopes) range across different spatial scales and concentrations on lanl land. thi ... | 2002 | 12009129 |
| mechanisms of evolutionary change in structural plumage coloration among bluebirds (sialia spp.). | combinations of microstructural and pigmentary components of barbs create the colour displays of feathers. it follows that evolutionary changes in colour displays must reflect changes in the underlying production mechanisms, but rarely have the mechanisms of feather colour evolution been studied. among bluebirds in the genus sialia, male rump colour varies among species from dark blue to light blue while breast colour varies from blue to rusty. we use spectrometry, transmission electron microsco ... | 2006 | 16849249 |
| age-based discrimination of rival males in western bluebirds. | adaptive social behavior frequently involves discriminating between classes of individuals such as relatives versus non-relatives, older versus younger individuals, or individuals of different status. in the absence of spatial cues, this discrimination may be based on signals that correlate with fitness-related traits (e.g., older or high-status males may sing higher performance songs) or with identity, for example, when receivers distinguish and classify signalers based on their unique signal s ... | 2016 | 27271774 |
| protocols for metagenomic dna extraction and illumina amplicon library preparation for faecal and swab samples. | next-generation sequencing (ngs) technology has extraordinarily enhanced the scope of research in the life sciences. to broaden the application of ngs to systems that were previously difficult to study, we present protocols for processing faecal and swab samples into amplicon libraries amenable to illumina sequencing. we developed and tested a novel metagenomic dna extraction approach using solid phase reversible immobilization (spri) beads on western bluebird (sialia mexicana) samples stored in ... | 2014 | 24774752 |
| microbial and environmental effects on avian egg viability: do tropical mechanisms act in a temperate environment? | the viability of freshly laid avian eggs declines after several days of exposure to ambient temperatures above physiological zero, and declines occur faster in tropical than temperate ecosystems. microbial infection during preincubation exposure has recently been shown as a second cause of egg viability decline in the tropics, but whether microbial processes influence the viability of wild bird eggs in temperate ecosystems is unknown. we determined the microbial load on eggshells, the incidence ... | 2011 | 21661574 |
| horsehair worms (gordius robustus in nests of the western bluebird (sialia mexicana): evidence for anti-predator avoidance? | hairworms (nematomorpha: gordiida) are internal parasites that alter the behavior of their terrestrial insect host, forcing it to enter the water to reach its reproductive habitat. after reproduction of the free-living adults, the larvae encyst in aquatic insects and are retained upon metamorphosis of the insect into an adult fly. this paratenic host links the aquatic and terrestrial environments after its consumption by omnivorous or predatory insects. therefore, hairworms are usually only asso ... | 2010 | 19954262 |
| maternal effects and range expansion: a key factor in a dynamic process? | species that depend on ephemeral habitat often evolve distinct dispersal strategies in which the propensity to disperse is closely integrated with a suite of morphological, behavioural and physiological traits that influence colonizing ability. these strategies are maintained by natural selection resulting from spatial and temporal variation in resource abundance and are particularly evident during range expansion. yet the mechanisms that maintain close alignment of such strategies with resource ... | 2009 | 19324612 |
| development and cross-species testing of western bluebird (sialia mexicana) microsatellite primers. | western and eastern bluebirds (sialia mexicana and s. sialis) are socially monogamous passerines that engage in extra-pair copulations. we obtained microsatellites from s. mexicana and optimized and characterized 15 microsatellite dna loci in 60 individuals of this species. primer pairs yielded an average of 13 alleles per locus in western bluebirds (range 3-35 alleles) with an average observed heterozygosity of 0.68 (range 0.27-0.88). all 15 loci also successfully amplified in s. sialis (n = 24 ... | 2008 | 21586042 |
| first evidence for heritable variation in cooperative breeding behaviour. | understanding the evolution of complex social behaviours, such as cooperative breeding, is a fundamental problem in evolutionary biology, which has attracted much theoretical and empirical interest. variation within and between species in the frequency of helping behaviour has been typically associated with variation in direct costs and benefits due to ecological constraints, or with indirect fitness payoffs (i.e. kin selection). here, we provide the first evidence that individual variation in c ... | 2007 | 17490945 |
| aggressive behaviour affects selection on morphology by influencing settlement patterns in a passerine bird. | the importance of behaviours as instigators or inhibitors of evolutionary change remains largely unresolved and this is in part because there are very few empirical examples of how behaviours affect evolutionary processes. by determining the environment of breeding, aggressive interactions over territories have the potential to strongly impact selection pressures experienced by individuals. western bluebirds (sialia mexicana) provide a unique opportunity to investigate the evolutionary importanc ... | 2006 | 16790412 |
| winter resource wealth drives delayed dispersal and family-group living in western bluebirds. | delayed dispersal, where offspring remain with parents beyond the usual period of dependence, is the typical route leading to formation of kin-based cooperative societies. the prevailing explanations for why offspring stay home are variation in resource wealth, in which offspring of wealthy parents benefit disproportionately by staying home, and nepotism, where the tendency for parents to be less aggressive and share food with offspring makes home a superior place to wait to breed. these hypothe ... | 2005 | 16243691 |
| family-based winter territoriality in western bluebirds, sialia mexicana: the structure and dynamics of winter groups. | winter residency is characteristic of the majority of cooperatively breeding birds, but the composition and dynamics of winter groups have been examined in relatively few. in 1996-1998, we examined winter territoriality in the western bluebird, a year-round resident that shows a limited degree of helping behaviour in central coastal california, u.s.a. in spring, most western bluebirds breed as socially monogamous pairs, but a small proportion of pairs (3-16%) have additional breeding-age males h ... | 2001 | 11170701 |
| acanthocephalan parasitism in the western bluebird (sialia mexicana). | acanthocephalan parasites of the species plagiorhynchus (prosthorhynchus) formosus van cleave, 1918, were recovered from the intestinal tracts of two male and two female wild western bluebirds (sialia mexicana). parasitism by p. formosus was considered to be a contributory cause of death of these breeding adult bluebirds. this is the first reported recovery of acanthocephalan parasites from western bluebirds. | 2003 | 526209 |
| does vitamin e supplementation enhance growth benefits of breeding helpers at no oxidative costs? | during early postnatal development, biomolecules are particularly exposed to the detrimental actions of unneutralized reactive oxygen species. these prooxidant molecules have been claimed to mediate the trade-off between growth and somatic maintenance. vitamin e is a key exogenous antioxidant that plays an important role in protecting biological membranes against oxidative damage. however, evidence of the effect of vitamin e supplementation during early life on growth and oxidative status in wil ... | 2020 | 31718435 |
| long-term phenology of two north american secondary cavity-nesters in response to changing climate conditions. | wildlife populations can respond to changes in climate conditions by either adapting or moving to areas with preferred climate regimes. we studied nesting responses of two bird species, western bluebird (sialia mexicana) and ash-throated flycatcher (myiarchus cinerascens), to changing climate conditions (i.e., rising temperatures and increased drought stress) over 21 years in northern new mexico. we used data from 1649 nests to assess whether the two species responded to changing climate conditi ... | 2019 | 31605239 |
| long-term variation in environmental conditions influences host-parasite fitness. | long-term data on host and parasite fitness are important for predicting how host-parasite interactions will be altered in an era of global change. here, we use data collected from 1997 to 2013 to explore effects of changing environmental conditions on bird-blowfly interactions in northern new mexico. the objectives of this study were to examine what climate variables influence blowfly prevalence and intensity and to determine whether blowflies and climate variables affect bird fledging success. ... | 2019 | 31346432 |
| precision gain versus effort with joint models using detection/non-detection and banding data. | capture-recapture techniques provide valuable information, but are often more cost-prohibitive at large spatial and temporal scales than less-intensive sampling techniques. model development combining multiple data sources to leverage data source strengths and for improved parameter precision has increased, but with limited discussion on precision gain versus effort. we present a general framework for evaluating trade-offs between precision gained and costs associated with acquiring multiple dat ... | 2019 | 30766670 |
| effects of experimental anthropogenic noise exposure on the reproductive success of secondary cavity nesting birds. | artificial nest boxes are critical nesting sites for secondary cavity-nesting birds; however, they are often placed near roadways and in urban areas that experience noise pollution and other human-caused stressors. recent correlative studies document both negative and positive influences of noise pollution on reproductive success. additionally, observational studies have not determined which stage of the breeding process is most vulnerable to noise pollution-settlement, incubation, and/or provis ... | 2018 | 29945170 |
| chronic anthropogenic noise disrupts glucocorticoid signaling and has multiple effects on fitness in an avian community. | anthropogenic noise is a pervasive pollutant that decreases environmental quality by disrupting a suite of behaviors vital to perception and communication. however, even within populations of noise-sensitive species, individuals still select breeding sites located within areas exposed to high noise levels, with largely unknown physiological and fitness consequences. we use a study system in the natural gas fields of northern new mexico to test the prediction that exposure to noise causes glucoco ... | 2018 | 29311304 |
| effects of load-lightening and delayed extrapair benefits on the fitness consequences of helping behavior. | in most cooperative breeders, helping is directed at close kin, allowing helpers to gain indirect fitness benefits by increasing the reproductive success of close relatives, usually their parents. extrapair paternity (epp) occurs at high rates in some cooperative breeders, reducing the relatedness of helpers to the young they help raise. even so, a son that helps is related to the brood by at least 0.25 through his mother and to within-pair young by 0.5, whereas a potential helper that has epp i ... | 2020 | 30349177 |