| 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 |
| songbird response to increased willow (salix spp.) growth in yellowstone's northern range. | after nearly a century of height suppression, willows (salix spp.) in the northern range of yellowstone national park, u.s.a., are increasing in height growth as a possible consequence of wolf (canis lupus) restoration, climate change, or other factors. regardless of the drivers, the recent release of this rare but important habitat type could have significant implications for associated songbirds that are exhibiting declines in the region. our objective was to evaluate bird response to releasin ... | 2011 | 21939061 |
| use of data on avian demographics and site persistence during overwintering to assess quality of restored riparian habitat. | monitoring responses by birds to restoration of riparian vegetation is relatively cost-effective, but in most assessments species-specific abundances, not demography, are monitored. data on birds collected during the nonbreeding season are particularly lacking. we captured birds in mist nets and resighted banded birds to estimate species richness and diversity, abundance, demographic indexes, and site-level persistence of permanent-resident and overwintering migrants in remnant and restored ripa ... | 2012 | 22443304 |
| sex differences in forebrain monoaminergic response to song performance. | in many species, successful reproduction is dependent on the ability to adjust social behavior in response to an ever-changing social environment. because a sexual signal's value and meaning can differ between females and males, responses to those signals should also differ. one way individuals can modulate social behavior is through experience-dependent modulation of the sensory systems that process social signals. central monoamines (norepinephrine, dopamine, serotonin) modulate neural sensiti ... | 2017 | 28482339 |
| the regulation of behavioral plasticity by performance-based feedback and an experimental test with avian egg production. | optimizing plasticity in behavioral performances requires the abilities to regulate physiological effort and to estimate the effects of the environment. to describe how performance-based feedback could play a role in regulating recursive or continuous behavioral performances, i developed two models, one (environmental feedback) that assumes an initial ability to regulate effort but not to predict the effects of the environment and the other (effort feedback) that assumes an initial ability to pr ... | 2016 | 27104990 |
| contrast influences female attraction to performance-based sexual signals in a songbird. | animals do not make decisions in a bubble but often refer to previous experience when discriminating between options. contrast effects occur when the value of a stimulus affects the response to another value of the stimulus, and the changes in value and response are in the same direction. although contrast effects appear irrational, they could benefit decision makers when there is spatial or temporal variation and autocorrelation in the value of stimuli that elicit decisions. here, we examined w ... | 2014 | 25319818 |
| song competition affects monoamine levels in sensory and motor forebrain regions of male lincoln's sparrows (melospiza lincolnii). | male animals often change their behavior in response to the level of competition for mates. male lincoln's sparrows (melospiza lincolnii) modulate their competitive singing over the period of a week as a function of the level of challenge associated with competitors' songs. differences in song challenge and associated shifts in competitive state should be accompanied by neural changes, potentially in regions that regulate perception and song production. the monoamines mediate neural plasticity i ... | 2013 | 23555809 |
| song in the cold is 'hot': memory of and preference for sexual signals perceived under thermal challenge. | the environmental conditions under which signals are perceived can affect receiver responses. many songbird populations produce a song chorus at dawn, when, in cold habitats, they would experience thermal challenge. we recorded temperature and the song activity of lincoln's sparrows (melospiza lincolnii) on a high-elevation meadow, and determined that song behaviour is concentrated around the coldest time of the day, at dawn. we hypothesized that this is because male song in the cold is more att ... | 2012 | 22809726 |
| one meadow for two sparrows: resource partitioning in a high elevation habitat. | resource partitioning is the basis of the coexistence of sympatric species and has therefore received much attention in ecological studies. however, how variation in environmental conditions (and particularly natural variation in resource availability) can influence resource partitioning in free-ranging animals is not well understood. in the present study, we addressed the hypothesis that natural changes in the availability of food resources affect food partitioning between sympatric species. to ... | 2012 | 22526943 |
| female lincoln's sparrows modulate their behavior in response to variation in male song quality. | sexually reproducing organisms should mate with the highest quality individuals that they can. when female songbirds choose a mate, they are thought to use several aspects of male song that reflect his quality. under resource-limited environmental conditions, male lincoln's sparrows (melospiza lincolnii) vary among one another in several aspects of song quality, including song length, song complexity, and trill performance. in a 2-pronged approach, we tested whether variation in song quality of ... | 2010 | 22476505 |
| song environment affects singing effort and vasotocin immunoreactivity in the forebrain of male lincoln's sparrows. | male songbirds often establish territories and attract mates by singing, and some song features can reflect the singer's condition or quality. the quality of the song environment can change, so male songbirds should benefit from assessing the competitiveness of the song environment and appropriately adjusting their own singing behavior and the neural substrates by which song is controlled. in a wide range of taxa, social modulation of behavior is partly mediated by the arginine vasopressin or va ... | 2010 | 20399213 |
| annual variation in vocal performance and its relationship with bill morphology in lincoln's sparrows. | morphology may affect behavioural performance through a direct, physical link or through indirect, secondary mechanisms. although some evidence suggests that the bill morphology of songbirds directly constrains vocal performance, bill morphology may influence vocal performance through indirect mechanisms also, such as one in which morphology influences foraging and thus the ability to perform some types of vocal behaviour. this raises the possibility for ecologically induced variation in the rel ... | 2009 | 20160859 |
| ovulation order mediates a trade-off between pre-hatching and post-hatching viability in an altricial bird. | simultaneously dependent siblings often compete for parentally provided resources. this competition may lead to mortality, the probability of which may be a function, in part, of the individual offspring's production order. in birds, serial ovulation followed by hatching asynchrony of simultaneous dependents leads to differences in post-hatching survival that largely depend on ovulation (laying) order. this has led to the widespread assumption that early-laid eggs are of greater value and theref ... | 2008 | 18335056 |
| how song experience affects female mate-choice, male song, and monoaminergic activity in the auditory telencephalon in lincoln's sparrows. | a sexual signal can indicate not only the signaler's attractiveness as a potential mate but also the signaler's competitiveness relative to rivals. as the attractiveness or competitiveness of the prevailing signaling environment increases, individuals prospecting for mates should change their choice threshold, whereas competing individuals should shift resources toward elevating their own competitiveness. previous studies show that experimental elevations of song competition increase male compet ... | 2017 | 28992115 |
| oviposition drives hatching order and developmental disparities with brood mates. | birth or hatching order can affect fitness. it has long been assumed that the order in which a bird's egg is laid (its oviposition) and first exposed to incubation relative to other eggs in the nest determines the order in which it hatches and the subsequent effects on development and survival. to my knowledge, this cause of hatching order has not been tested while controlling for laying-order effects on egg composition. like those of many species, the last-laid eggs in clutches of the lincoln's ... | 2018 | 30958248 |