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At least 19 recordsLinked to original sources
PubMed2000

Multiple levels of representation of song by European starlings (Sturnus vulgaris): open-ended categorization of starling song types and differential forgetting of song categories and exemplars.

Four European starlings (Sturnus vulgaris) were trained to discriminate among conspecific and heterospecific song segments in a go/no-go operant task. In Experiment 1, the starlings discriminated among novel starling and heterospecific songs, indicating an open-ended category of conspecific song types. The starlings also showed excellent memory for reinforced conspecific songs and discriminated among subordinate categories of conspecific song. In Experiment 2, the starlings were presented with the song segments from Experiment 1 after an 8-month delay period. The starlings retained the discrimination between conspecific and heterospecific songs but not among conspecific songs. The starlings also retained memory for individual singers over the 8-month delay. Starlings categorize song at the level of species, and at subordinate categories of song types, and may have superior long-term retention of song categories relative to song exemplars.

Animals↗
PubMed2001

Interrupted blood-feeding by Culiseta melanura (Diptera: Culicidae) on European starlings.

To determine whether Culiseta melanura (Coquillett) mosquitoes tend to take multiple blood meals when birds of certain species serve as hosts, we compared the frequencies with which such mosquitoes fed upon caged starlings and robins and determined whether similar volumes of blood were imbibed from each. The blood of robins (Turdus migratorius) and European starlings (Sturnus vulgaris) was marked contrastingly by injecting birds with rubidium or cesium salts. Caged birds were placed together in a natural wetland setting overnight. Mosquitoes captured nearby on the following morning were analyzed for each of the elemental markers. Where marked robins and starlings were equally abundant, 43% of freshly engorged Cs. melanura fed on more than or equal to two hosts. More Cs. melanura fed on robins than on starlings. Individual mosquitoes tended to contain far more robin- than starling-associated marker, indicating that mosquitoes "feasted" on robins but only "nibbled" on starlings. Mosquitoes marked with both elements apparently fed meagerly on the starlings then abundantly on the robins. Our estimates of bloodmeal volume indicate that 85% of mosquitoes that fed on marked starlings obtained < 0.5 microliter of blood from them. We suggest that defensive behavior by starlings interrupts mosquito blood-feeding and that, in a communal roost of starlings, each mosquito will tend to feed on more than one bird, thereby promoting rapid transmission of such ornithonotic arboviruses as eastern equine encephalomyelitis virus and West Nile virus.

Animals↗
PubMed2000

Perceptual classification based on the component structure of song in European starlings.

The ability to recognize individuals based on their vocalizations is common among many species of songbirds. Examining the psychological and neural basis of this functionally relevant behavior can provide insight into the perceptual processing of acoustically complex, real-world, communication signals. In one species of songbird, European starlings (Sturnus vulgaris), males sing long and acoustically complex songs composed of small stereotyped note clusters called motifs. Previous studies demonstrate that starlings are capable of individual vocal recognition, and suggest that vocal recognition results from the association of specific motifs with specific individuals. The present study tests this possibility by examining how variation among the motifs that comprise a song affect its discrimination and classification. Starlings were trained, using operant techniques, to associate multiple songs from a single male starling with one response, and songs from four other male starlings with another response. The level of stimulus control exerted by motif variation was then measured by having subjects classify three sets of novel song bouts in which motifs from the training songs were systematically recombined. The results demonstrate a significant, and approximately linear, relationship between song classification and the relative proportions of familiar motifs from different singers that compose a bout. The results also indicate that the motif proportion effects on song classification are primary to retroactive interference in the recall for specific motifs, and independent of any biases due to the syntactic organization of motifs within a bout. Together, the results of this study suggest that starlings organize the complex vocalizations of conspecifics by memorizing large numbers of unique song components (i.e., motifs) that are then associated with different classes. Because individual starlings tend to possess unique motif repertoires, it is likely that under natural conditions such classes will correspond to individual identity. Thus, it is likely that perceptual processing mechanisms similar to those described by the results of the present study form the basis for individual vocal recognition in starlings.

Animal Communication↗
PubMed1980

Effects of phosphate loading and parathyroid hormone on starling renal phosphate excretion.

The effects of phosphate loading were examined in intact, parathyroidectomized (PTX), and PTX starlings infused with parathyroid extract (PTX +/- PTE). In intact starlings, there was no correlation between the filtered phosphate load and the quantity of phosphate excreted. Net secretion predominated at lower filtered loads (2.5-20 mu mol . kg-1 . min-1) but net reabsorption occurred at filtered loads between 20 and 35 mu mol . kg-1 . min-1. Phosphate-loaded PTX starlings reabsorb phosphate over a wide range of filtered loads (5-45 mu mol . kg-1 . min-1). Excretion was significantly correlated with the filtered load in PTX birds (r = 0.943). Phosphate loaded PTX + PTE starlings secreted phosphate when filtered loads ranged from 2.5 to 30 mu mol . kg-1 . min-1. Excretion also was significantly correlated with the filtered load in this group (r = 0.972). The results of these experiments indicate that a) variations in endogenous PTH release in intact starlings result in wide variations in the renal pattern of phosphate excretion during phosphate loading; b) net phosphate secretion rarely occurs during phosphate loading in PTX starlings, but always occurs in PTX + PTE starlings; and c) both phosphate secretion and phosphate reabsorption are limited by maximal tubular transport capacities. Additional evidence indicates that PTH inhibits tubular phosphate reabsorption in starlings.

Animals↗
PubMed2000

Female European starling preference and choice for variation in conspecific male song.

Data from several field studies support the hypothesis that female European starlings, Sturnus vulgaris, attend to variation among the songs of conspecific males when making mate-choice decisions. However, for a variety of methodological reasons, direct evidence for female preferences based on song in starlings has been lacking. This study presents a novel technique for assaying directly female preference and choice in European starlings by using the presentation of conspecific male song as an operant reinforcer in a controlled environment. Using an apparatus in which the playback of songs from different nestboxes is under the operant control of the subject, we demonstrate how the reinforcing properties of conspecific song can be used to measure female preference and choice. The results of the study suggest three conclusions. First, female starlings prefer naturally ordered conspecific male songs over reversed songs. Second, female starlings display robust preferences for longer compared with shorter male song bouts. Behaviour in the operant apparatus varied directly with male song bout length. Third, preferences based on song bout length are sex specific. Male starlings failed to respond differentially to the same stimuli for which females showed strong preferences. These results suggest that male-male variation in song bout length is important for mate choice among starlings. In addition, we detail the use of a novel behavioural assay for measuring female preferences that can be applied to similar behaviours in other species of songbirds. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Predicting starling chick carcass PCB concentrations from PCB concentrations in ingested animal matter.

Preremediation studies at Crab Orchard National Wildlife Refuge (CONWR) revealed statistically significant accumulations of polychlorinated biphenyls (PCBs) and effects in starling chicks (Sturnus vulgaris) from contaminated sites, including decreased nest attentiveness, decreased fledging success, and an increase in chick mortality. Although the expected route of exposure for starling chicks is thought to be via diet, this has not previously been documented at CONWR. The purpose of this study was to develop an equation to predict starling chick carcass PCB concentrations from PCB concentrations in ingested animal matter. During 1995 and 1996, stomach contents from 14 and 22 starling chicks collected from contaminated and reference sites, respectively, were evaluated. Animal, plant, and mineral matter in the stomach contents were separated and animal matter from stomachs of individuals from the same nest were combined, dried, and percent dry weight calculated. Composite samples of animal matter were then analyzed for the presence of PCBs (Aroclor 1254). Stomach contents were primarily composed of animal matter (76%), and the percent animal matter in the stomachs did not differ significantly among locations (range = 38.4% to 100%). The mean PCB concentration in composite samples of animal matter from stomachs of chicks collected from contaminated sites (1.82 +/- 1.17 mg/kg) was significantly greater than the concentrations in composite samples from two reference locations (<0. 24 mg/kg). PCB concentrations in stomach contents were correlated (Pearson correlation coefficient = 0.91, p < 0.005) with concentrations in carcasses of chicks from which the stomachs had been collected. The regression Y = 6.19 x X(1,398), where Y = starling chick carcass PCB concentration and X = starling stomach animal matter PCB concentration, indicated that PCB concentrations in consumed animal matter accounted for 82% of the variability in starling carcass concentrations.http://link.springer-ny. com/link/service/journals/00244/bibs/37n4p548.html</++ +HEA

Animals↗
PubMedDate not supplied

Effects of dietary quality on basal metabolic rate and internal morphology of European starlings (Sturnus vulgaris).

European starlings (Sturnus vulgaris) were fed either a low- or high-quality diet to test the effects of dietary quality on basal metabolic rate (BMR) and internal morphology. Basal metabolic rate did not differ significantly between the two dietary groups, but internal morphology differed greatly. Starlings fed the low-quality diet had heavier gastrointestinal tracts, gizzards, and livers. Starlings fed the high-quality diet had heavier breast muscles. Starlings on the low-quality diet maintained mass, while starlings on the high-quality diet gained mass. Dry matter digestibility and energy digestibility were lower for starlings fed the low-quality diet, and their food and water intake were greater than starlings on the high-quality diet. The lack of dietary effect on BMR may be the result of increased energy expenditure of digestive organs paralleling a reduction of energy expenditure of organs and tissues not related to digestion (i.e., skeletal muscle). This trade-off in energy allocation among organs suggests a mechanism by which organisms may alter BMR in response to a change in seasonal variation in food availability.

Animals↗
PubMed1998

[Swarms of starlings in Basel: a natural phenomenon, a nuisance or a health risk?].

A Natural Phenomenon, Molestation or a Health Risk? For the last two decades an avenue in the centre of Basel (Altrheinweg, Klybeckquartier) is known as site for overnight accommodation and assembly of starlings (Sturnus vulgaris) during autumn. The nightly visitors cause an immense contamination that directly affects a nursery and a primary school. The aim of the present study was the evaluation of the health risk for the population due to the starlings' droppings, particularly for the children from the nursery school. Between August and December of the years 1995 and 1996 the population of starlings was observed, the contamination of the area with faeces was quantified, the presence of microorganisms in the faeces was determined and the contamination of the soil from the Altrheinweg was compared with that from other avenues and parks. Furthermore, the children attending the nursery school were monitored for possible infections due to the birds' droppings. In mid-October, when the population of starlings reached their maximum of about 15,000 birds, 1053 defecations per night and square metre were counted on an average in 1995 and 1821 in 1996. The microbiological analysis of the starlings' faeces showed a high contamination with Campylobacter spp. (1995: 95.5%; 1996: 100%), L. monocytogenes (1995: 36.5%; 1996: 26.7%) and C. psittaci (1995: 40.5%), a lower contamination with Salmonella spp. (1995: 1.0%), S. aureus (1995: 2.0%), Y. enterocolitica (1995: 1.5%) and Y. pseudotuberculosis (1995: 1.0%). Mycotic and parasitic human pathogens were not found. The contamination of the soil from the Altrheinweg with Campylobacter spp. and L. monocytogenes was significantly greater than that of the other avenues and parks in Basel. However, the investigations conducted by the school medical service showed that no infections among the children attending the nursery school could be correlated to the presence of the starlings. Even if the heavy contamination of the area with droppings of starlings presents a potential health risk, a continuous or systematic transmission of infectious agents seems rather improbable due to the contamination-avoiding behaviour of the children, the characteristics of the microorganisms involved and the climatic conditions in autumn. This situation showed however not reduce our awareness of such a potential health risk.

Animals↗
PubMed2005

Effects of arginine vasotocin (AVT) on the behavioral, cardiovascular, and corticosterone responses of starlings (Sturnus vulgaris) to crowding.

Previous studies in European starlings have concluded that conspecific crowding can be a significant stressor that is capable of simultaneously altering behavior, heart rate, and corticosterone (CORT) concentrations. It was hypothesized that the peptide hormone arginine vasotocin (AVT) has a role in the regulation of these three types of responses to crowding. Four male and four female resident starlings were submitted to nine combinations of 3 crowding treatments (0, 1, or 5 intruder starlings) and 3 subcutaneous injections (1, 4 microg AVT, and saline control). Resident starlings were given a treatment injection, their heart rate and behavior were monitored for 30 min, 0, 1, or 5 intruder Starlings were allowed to enter the residents cage, and HR and behavior were monitored for another 30 min. Blood samples were taken before and after all treatments to assess CORT concentrations. Exogenous AVT decreased the frequency of maintenance behaviors (feeding, drinking, preening, and beak wiping), as well as activity in resident starlings. Although aggressive behaviors upright posture, head feather expansion, and pecking) increased during crowding, these increases were significantly attenuated by AVT. Heart rate was significantly lower during these behavioral effects, and the CORT data indicate that the cardiovascular and behavioral effects are not dependent on significant increases in CORT. These data support the hypothesis that AVT's attenuation of general behavior and crowding induced aggression are modulated by a cardiovascular mechanism.

Aggression↗
PubMed2003

Behavioral, physiological, and endocrine responses of starlings to acute increases in density.

One potential stressor to vertebrates both in the wild and in captivity is the presence of numerous individuals in a confined space. To examine the effects of increased conspecific density in birds, we simultaneously measured cardiac, behavioral, and endocrine responses of European starlings (Sturnus vulgaris) to acute crowding. A cage containing a resident bird was outfitted with a trap door that allowed for the introduction of intruder birds (one, three, or five birds) without human interference. The resident bird was implanted with a subcutaneous heart rate (HR) transmitter, behavior was videotaped through a two-way mirror, and blood samples were taken at the end of each treatment to determine plasma corticosterone (CORT) concentrations. Resident starlings significantly increased both general activity and aggressive behaviors while decreasing preening following the initiation of elevated conspecific density. Intruder starlings increased feeding, drinking, and aggressive pecking rates, but postintrusion feeding rates decreased as intruder number increased. Preening decreased in both residents and intruders following the intrusion. HR increased in the resident starlings at the time of intruder introduction, with an increase in the magnitude of this response directly correlating with increasing intruder number. The CORT response to increased density was dependent on social role (resident or intruder), since increasing density did not alter CORT levels in resident birds, but resulted in elevated CORT 30 min following the five-intruder introduction in the intruder birds. Together, these data suggest that increased conspecific density is a significant acute stressor in starlings which is capable of inducing aggression in both residents and intruders. Furthermore, it elicits different responses from different physiological and behavioral systems, and behavioral responses such as feeding and general activity may be density-dependent. The data specifically illustrate that cardiac and behavioral activation can be independent of CORT release, and the CORT response of starlings to increased conspecific density is dependent on social role and degree of the increase in density.

Aggression↗
PubMed1978

Efficiency of the Frank-Starling mechanism at various levels of inotropy and afterload during aortic insufficiency in the dog.

Reversible aortic insufficiency was produced in six dogs before and during aortic contrictions at control myocardial inotropy, during high and low inotropy induced by calcium infusion and propranolol administration, respectively. Myocardial chord lengths (MCL) of the left ventricular wall were continuously recorded by ultrasonic technique. Activation of the Frank-Starling mechanism during aortic insufficiency was verified by an increase in end-diastolic length and systolic shortening of MCL. Efficiency of the Frank-Starling mechanism was calculated as the quotient between the rise in systolic shortening and the rise in end-diastolic MCL. At control blood pressure, the efficiency of the Frank-Starling mechanism was 59 +/- 3, 76 +/- 6 and 53 +/- 6% at control, high and low inotropy, respectively. After raising systolic ventricular pressure 30-40 mmHg by aortic constriction, the efficiency of the Frank-Starling mechanism decreased at control inotropy to 41 +/- 7 and at low inotropy to 32 +/- 9% but did not decrease significantly at high inotropy (70 +/- 6%). During periods with aortic insufficiency, left ventricular afterload is increased and it is concluded that the apparent greater efficiency of the Frank-Starling mechanism at high than at low inotropy. At either level of inotropy and afterload examined and at constant heart rate, the Frank-Starling mechanism was activated on a beat to beat basis.

Animals↗
PubMed1998

Melatonin, immunity and cost of reproductive state in male European starlings.

The effects of reproductive condition and exogenous melatonin on immune function were investigated in castrated European starlings, Sturnus vulgaris. Photorefractory and photostimulated starlings exposed to long days were implanted with melatonin or with blank capsules. Photostimulated starlings with blank capsules exhibited reduced splenocyte proliferation in response to the T-cell mitogen, concanavalin A, compared with the other long-day birds. Exogenous melatonin prevented the suppression of immune function by photostimulation. Photorefractory starlings, with or without melatonin implants, exhibited enhanced immune function compared with photostimulated starlings implanted with blanks. This enhancement was not mediated by endogenous melatonin, but appeared to be related to changes in reproductive state. In addition to the traditional costs of reproduction in birds (e.g. raising of young), there may be a cost of the reproductive state of starlings (i.e. whether they are photorefractory or photostimulated). These data are, we believe, the first to indicate a direct effect of reproductive state on immune function that is independent of both photoperiod (i.e., changes in the duration of melatonin secretion) and gonadal steroids.

Animals↗
PubMed2002

Myocardial response to incremental exercise in endurance-trained athletes: influence of heart rate, contractility and the Frank-Starling effect.

Recent evidence indicates that endurance-trained athletes are able to increase their stroke volume (SV) throughout incremental upright exercise, probably due to a progressively greater effect of the Frank-Starling mechanism. This is contrary to the widely held belief that SV reaches a plateau at a submaximal heart rate (irrespective of fitness level), owing to a limitation in the time for diastolic filling. The purpose of this investigation was to evaluate whether endurance-trained athletes rely on a progressively greater effect of the Frank-Starling mechanism throughout incremental exercise. A secondary purpose was to evaluate the effects of postural position on the cardiovascular responses to incremental exercise. Ten male cyclists participated in this investigation. Left ventricular function was assessed throughout incremental exercise in the supine and upright positions (counterbalanced) using radionuclide ventriculography. Stroke volume increased in a linear fashion during incremental exercise in both the upright and supine positions. The increases in cardiac output (Q) throughout incremental to maximal exercise (in both the supine and upright positions) were significantly related to changes in heart rate, myocardial contractility and the Frank-Starling mechanism. Percentage changes in end-diastolic volume and SV were significantly greater in the upright position versus the supine position, reflecting an increased reliance on the Frank-Starling effect to increase Q. We conclude from this investigation that highly trained endurance athletes are able to make progressively increasing usage of the Frank-Starling effect throughout incremental exercise. Postural position has a significant effect on the relative contribution of heart rate, myocardial contractility and the Frank-Starling mechanism to the increase in Q during exercise conditions.

Adolescent↗
PubMed1997

A direct comparison of photoperiodic time measurement and the circadian system in European starlings and Japanese quail.

The extent to which circadian rhythms are involved in photoperiodic time measurement in quail is enigmatic, and earlier investigations have produced results consistent with an hourglass clock or one involving damped circadian oscillators. To address the problem further, the present authors carried out a direct comparison between the clocks in quail and those in starlings. Starlings possess strongly self-sustaining circadian oscillators. In Experiment 1, comparisons of testicular growth were made between the two species when birds were exposed to light:dark (LD) 6:30, LD 6:18, and LD 18:6. Starlings grew their testes rapidly under both LD 6:30 and LD 18:6, and they became photorefractory (under LD 6:18, the testes remained undeveloped). Quail grew their testes rapidly under LD 18:6 but did not do so under LD 6:30 or LD 6:18. In Experiment 2, entrainment of the activity rhythm under cycles of LD 6:30 was investigated by measuring the phase of the rhythm after release into constant darkness (DD). Birds were exposed to either 10 cycles or 11 cycles of LD 6:30 prior to DD. Starlings maintained their 24-h rhythmicity under LD 6:30 and always free ran from the phase of the subjective day. By contrast, quail showed circadian activity approximately 24 h after every light pulse and free ran from the phase of the last light pulse received. In Experiment 3, phase response curves (PRCs) were generated to 6-h light pulses. The species were strikingly different; starlings produced a Type 1 PRC, whereas quail produced a Type 0 PRC. More important, in quail the 6-h light pulse had the same effect regardless of circadian time and in almost every case activity free ran from the position of the 6-h light pulse. The results in quail are consistent with the photoperiodic time measurement system being based on a weakly self-sustaining (rapidly damping) circadian system that is invariably reset by 6 h of light, whereas in starlings the pacemakers are strongly self-sustaining. The results support the notion that hourglass pacemakers can be highly damped circadian pacemakers.

Animals↗
PubMed1993

Perceptual organization of auditory temporal patterns in European starlings (Sturnus vulgaris).

The perception of continuously repeating auditory patterns by European starlings was explored in seven experiments. In Experiment 1, 4 starlings learned to discriminate between two continuously repeating, eight-element, auditory patterns. Each eight-element pattern was constructed from different temporal organizations of two elements differing in timbre. In Experiments 2-7, the repeating patterns were transformed in ways designed to identify the starlings' perceptual organization of the patterns. In Experiment 2, the starlings identified patterns beginning with novel starting points. In Experiment 3, discrimination performance was adversely affected by reorganizing the elements in the patterns. In Experiments 4 and 5, the pattern elements were altered. In Experiment 4, the patterns were constructed from two novel elements. In Experiment 5, the temporal location of the two pattern elements was reversed. The transformations of the patterns in Experiments 4 and 5 affected discrimination performance for some, but not all, of the starlings. In Experiments 6 and 7, replacing either of the two elements with silent intervals had no effect on discrimination performance. The results of these experiments identify basic grouping principles that starlings use when they perceive auditory patterns.

Animals↗
PubMed1999

Eastern equine encephalitis virus in birds: relative competence of European starlings (Sturnus vulgaris).

To determine whether eastern equine encephalitis (EEE) virus infection in starlings may be more fulminant than in various native candidate reservoir birds, we compared their respective intensities and durations of viremia. Viremias are more intense and longer lasting in starlings than in robins and other birds. Starlings frequently die as their viremia begins to wane; other birds generally survive. Various Aedes as well as Culiseta melanura mosquitoes can acquire EEE viral infection from infected starlings under laboratory conditions. The reservoir competence of a bird is described as the product of infectiousness (proportion of feeding mosquitoes that become infected) and the duration of infectious viremia. Although starlings are not originally native where EEE is enzootic, a starling can infect about three times as many mosquitoes as can a robin.

Aedes↗
PubMed2000

Lack of gonadotrophin-releasing hormone (GnRH) neuron response to decreasing photoperiod in thyroidectomized male starlings (Sturnus vulgaris).

Exposure of starlings to long days initially causes reproductive maturation, but eventually leads to photorefractoriness. During photorefractoriness, gonadotrophin-releasing hormone (GnRH) decreases in the GnRH cell bodies and fibers emanating from these to the median eminence, circulating gonadotrophin concentrations decrease to a minimum, and the gonads regress. Thyroidectomy profoundly affects these photoperiodic responses. In chronically thyroidectomized starlings, gonadal responses to changes in day length are attenuated. This investigation was conducted to determine whether, in the absence of gonadal responsiveness, the GnRH system of chronically thyroidectomized starlings responds to changes in day length. Two groups of thyroidectomized male starlings were transferred from short days (8L:16D) to long days (18L:6D) for four weeks, and testicular volume increased. One group was kept on long days (TxLD) and the other was returned to short days (TxSD). Testicular volume did not decrease in the TxSD group. The GnRH neurons of the two thyroidectomized groups were compared to those of two groups of intact starlings, one of them on long days and photorefractory (ILD), the other on short days and photosensitive (ISD). Group ILD had lower numbers of GnRH-stained cells than groups TxLD, TxSD and ISD, which did not differ in this respect. Similar differences were observed for GnRH cell size in the pre-optic area (POA) and for density of staining of GnRH fibers in the median eminence. The results confirm that thyroidectomy attenuates gonadal responses to change in day length and suggest that this results from an effect upon the central nervous system rather than a peripheral effect.

Animals↗