distribution and connections of inspiratory premotor neurons in the brainstem of the pigeon (columba livia). | we have recorded extracellular, inspiratory-related (ir) unit activity in the medulla at locations corresponding to those of neurons retrogradely labeled by injections of retrograde tracers in the lower brachial and upper thoracic spinal cord, injections that covered cell bodies and dendrites of motoneurons innervating inspiratory muscles. bulbospinal neurons were distributed throughout the dorsomedial and ventrolateral medulla, from the spinomedullary junction through about 0.8 mm rostral to th ... | 1997 | 9067829 |
existence of parvalbumin and biochemical characterization in quail and pigeon skeletal muscles with different fiber type compositions. | the localization of parvalbumin was determined in skeletal muscles with different fiber type compositions from quails (coturnix japonica) and pigeons (columba livia) by sandwich elisa. the biochemical profiles of these muscles were evaluated by the assay of total lactate dehydrogenase (ldh) activity as well as the ldh isozymes for anaerobic metabolism, and by the analysis of myoglobin for aerobic metabolism. the quail fast posterior latissimus dorsi (pld) with a lower myoglobin content and highe ... | 1997 | 9097460 |
development of the retinotectal system in the pigeon: a cytoarchitectonic and tracing study with cholera toxin. | the optic tectum of the pigeon (columba livia) is marked by morphological dorso-ventral and left-right differences. both features seem to be related to functional specializations, but the responsible developmental mechanisms are unclear. since the visual system becomes functional only after hatching, the developmental processes might be extended into the post-hatching period. the development of the asymmetries in the tectofugal system, however, depends on an asymmetric light stimulation acting a ... | 1997 | 9193729 |
[appearance of antibodies against borrelia burgdorferi in different populations of pigeons (columba livia var. domestica vel urbana]. | borrelia burgdorferi, the causative agent of lyme borreliosis, can infect both mammals and birds. the purpose of the present survey was to determine the presence of antibodies against b. burgdorferi in different populations of pigeons. 1043 sera from pigeons (carrier-, urban-, show-pigeons) were examined by standard serological methods. b.burgdorferi shows crossreaction with b. anserina. therefore all sera were evaluated by ifat and elisa for both borrelia species. the results demonstrate no evi ... | 1997 | 9198966 |
projections of the nucleus of the basal optic root in pigeons (columba livia) revealed with biotinylated dextran amine. | the nucleus of the basal optic root (nbor) of the accessory optic system is known to be involved in the analysis of the visual consequences of self-motion. previous studies have shown that the nbor in pigeons projects bilaterally to the vestibulocerebellum, the inferior olive, the interstitial nucleus of cajal, and the oculomotor complex and projects unilaterally to the ipsilateral pretectal nucleus lentiformis mesencephali and the contralateral nbor. by using the anterograde tracer biotinylated ... | 1997 | 9259487 |
the orientation of the e-vector of linearly polarized light does not affect the behaviour of the pigeon columba livia | orientation with reference to the time-compensated sun-azimuth compass has been established for the homing pigeon columba livia. previous qualitative studies claim that pigeons are sensitive to the orientation of a polarizer and it has been suggested that these animals are able to use sky-light polarization as an indirect reference to the sun's position when the latter is shielded from view. we report experiments which were undertaken to quantify the sensitivity of the homing pigeon to the orien ... | 1994 | 9317437 |
flight kinematics of black-billed magpies and pigeons over a wide range of speeds | to investigate how birds that differ in morphology change their wing and body movements while flying at a range of speeds, we analyzed high-speed (60 hz) video tapes of black-billed magpies (pica pica) flying at speeds of 4-14 m s-1 and pigeons (columba livia) flying at 6-20 m s-1 in a wind-tunnel. pigeons had higher wing loading and higher-aspect-ratio wings compared with magpies. both species alternated phases of steady-speed flight with phases of acceleration and deceleration, particularly at ... | 1996 | 9317775 |
effects of pineal indoles and parachlorophenylalanine on seasonal reproduction in the pigeon | the effect of melatonin, methoxytryptophol (ml), methoxytryptamine (mt) and parachlorophenylalanine (p-cpa) on the mass and histology of the testes and the adrenal and thyroid glands and on serum thyroid hormone levels have been studied in the recrudescent phase of the feral pigeon columba livia. all the pineal indoles showed a common anti-gonadal effect, resulting in the arrest of spermatogenesis and the degeneration of germ cells. treatment with melatonin resulted in adreno-cortical enlargemen ... | 1996 | 9318563 |
functional morphology of the vanes of the flight feathers of the pigeon columba livia | the functional morphology of feather vanes was examined by combining morphological examination with mechanical tests. a geometrical model was derived which related the in-plane behaviour of the vane to the orientation of the barbs and barbules. this predicted that the small branching angles of both barbs and proximal barbules should result in a vane which is easier to move distally than proximally. these predictions were verified by mechanical tests on primary and secondary feathers of the pigeo ... | 1995 | 9319072 |
two distinct populations of tectal neurons have unique connections within the retinotectorotundal pathway of the pigeon (columba livia). | the tectofugal pathway is a massive ascending polysynaptic pathway from the tectum to the thalamus and then to the telencephalon. in birds, the initial component of this pathway is known as the tectorotundal pathway; in mammals, it is known as the tectopulvinar pathway. the avian tectorotundal pathway is highly developed; thus, it provides a particularly appropriate model for exploring the fundamental properties of this system in all amniotes. to further define the connectivity of the tectorotun ... | 1997 | 9335427 |
incidence of air pollution in the pulmonary surfactant system of the pigeon (columba livia). | the integrity of both pulmonary surfactant and surfactant producing cells, type ii pneumocytes, is essential for normal pulmonary function. almost all studies about air pollution effects on the pulmonary surfactant system have been performed by biochemical techniques, using atmospheric pollutants in a much higher concentration than that found in polluted city air. a comparative study of the number of lamellar bodies (lb) (pulmonary surfactant precursors) from type ii pneumocytes of pigeon lungs ... | 1997 | 9335466 |
intestinal cryptosporidiosis in pigeons (columba livia). | an intestinal disease in pigeons (columba livia) from the canary islands characterized by diarrhea and body weight loss is described. intestinal cryptosporidiosis was identified in three young pigeons. cryptosporidia were associated with hyperplasia of the intestinal crypts and moderate inflammatory infiltration in lamina propria. this is the first report of cryptosporidiosis in pigeons. | 1997 | 9356726 |
the contractile properties of the m. supracoracoideus in the pigeon and starling: a case for long-axis rotation of the humerus | wing upstroke in birds capable of powered flight is kinematically the most complicated phase of the wingbeat cycle. the m. supracoracoideus (sc), generally considered to be the primary elevator of the wing, is a muscle with a highly derived but stereotyped morphology in modern flying birds. the contractile portion of the sc arises from a ventral sternum, but its tendon of insertion courses above the glenohumeral joint to insert on the dorsal surface of the humerus. to clarify the role of the sc ... | 1997 | 9359888 |
habituation to sound during morning and night sessions in pigeons (columba livia). | habituation to acoustic stimulation was analyzed through night and morning sessions in pigeons submitted to a 12:12 h light-dark (ld) cycle. we demonstrate a lack of habituation in nocturnal sessions as compared to typical habituation curves in morning sessions. temporal organization of the habituation process raises issues concerning the biological meaning of sound in adaptation to the environment and/or the possible interaction of well known endogenous physiological rhythms with learning. a se ... | 1997 | 9383103 |
goal recognition and hippocampal formation in the homing pigeon (columba livia). | stimulus control of food-site recognition and role of the hippocampal formation (hf) were investigated. control and hf-lesioned pigeons were trained to find food located in a colored bowl, near a landmark beacon, in a constant room location. during later test trials, the sources of information were individually removed and/or disassociated. for all test trial types, hf-lesioned pigeons consistently chose bowls associated with one of the training stimuli. controls were more sensitive to the chang ... | 1997 | 9438793 |
thermal control of metabolic cold defence in pigeons columba livia | metabolic rate (mr) and various body temperatures were recorded in pigeons columba livia during gradual lowering of the ambient temperature (ta) and during cold exposure (-10 degrees c) for an entire circadian cycle. the aim was to study how changes in mr accorded with the observed body temperature displacements and our knowledge of regional cold sensitivity. when ta was lowered from 28 to -10 degrees c, the threefold increase in mr was accompanied by a significant increase in deep-body and spin ... | 1998 | 9464960 |
some bacterial enteropathogens in wildlife and racing pigeons from trinidad. | fecal and cloacal swabs or feces of wild mammalian, avian and reptilian species, either farmed or free-ranging, and of racing pigeons (columba livia) kept in lofts were cultured for salmonella spp., campylobacter spp., and yersinia spp. of 291 free-ranging mammals tested, 6 (2%) and 1 (< 1%) yielded positive cultures of salmonella spp. and campylobacter spp., respectively. salmonella newport was the predominant serotype isolated and the opossum (didelphis marsupialis insularis) had the significa ... | 1998 | 9476228 |
receptive field properties of visual neurons in the avian nucleus lentiformis mesencephali. | the receptive field (rf) properties of visual neurons extracellularly recorded from the nucleus lentiformis mesencephali (nlm) in pigeons (columba livia) were quantitatively analyzed using a workstation computer. these cells were actively spontaneous, and direction-and velocity-selective. using spatial gratings as visual stimuli, these cells could be divided into three groups: uni- (74%), bi- (17%), and omnidirectional (9%) cells in terms of their directionality. on the basis of their velocity s ... | 1998 | 9547098 |
coxiellosis in domestic and wild birds from japan. | serological evidence of infection with coxiella burnetii was found in 41 (2%) of 1,951 domestic birds and in 167 (19%) of 863 wild birds from 17 and 5 prefectures in japan, respectively, by microagglutination (ma) test. the bacteriological evidence of the infection was found in 17 (41%) of 41 domestic birds and 37 (22%) of 167 wild birds by the nested polymerase chain reaction (pcr). in addition, c. burnetii was isolated from five each of serum, spleen and fecal specimens from five jungle crows ... | 1998 | 9577778 |
visual pigments and oil droplets from six classes of photoreceptor in the retinas of birds. | microspectrophotometric examination of the retinal photoreceptors of the budgerigar (shell parakeet), melopsittacus undulatus (psittaciformes) and the zebra finch, taeniopygia guttata (passeriformes), demonstrate the presence of four, spectrally distinct classes of single cone that contain visual pigments absorbing maximally at about 565, 507, 430-445 and 360-380 nm. the three longer-wave cone classes contain coloured oil droplets acting as long pass filters with cut-offs at about 570, 500-520 a ... | 1997 | 9578901 |
lead concentration in the bones of the feral pigeons (columba livia): sources of variation relating to body condition and death. | this paper reports on lead concentrations in the tarsometatarsi of 84 individuals of adult feral pigeons columba livia found dead or experimentally captured in bratislava, slovakia. the interrelationships between lead concentrations and time of death, place of death, body measurements, sex, condition, and plumage phenotype were investigated. size and shape of pigeons was not correlated with bone lead contamination. sex and plumage color and pattern were slightly associated with variation in bone ... | 1998 | 9601922 |
drug discrimination history: pigeons trained to discriminate opioids with activity at different receptor types. | in pigeons (columba livia; n = 5) trained to discriminate the mu (mu) opioid butorphanol from saline, various mu (morphine, fentanyl) but not kappa (kappa; bremazocine, u50,488, u69,593) opioids produced at least 80% drug-appropriate responding. subsequently, pigeons were retrained to discriminate the kappa opioid bremazocine from saline; in this condition, both mu and kappa opioids produced at least 80% drug-appropriate responding, naloxone was more potent as an antagonist of the butorphanol st ... | 1998 | 9608345 |
bionomics and laboratory transmission of haemoproteus columbae kruse by pseudolynchia canariensis maquart (diptera: hippoboscidae) to two bird hosts in egypt. | pseudolynchia canariensis succeeded to feed and survive normally on both streptopelia senegallus and s. turtur. the feeding period, blood meal ratio and longevity of both male and female flies did not differ significantly (p > 0.05) from the corresponding values for the natural host columba livia. infection of s. senegallus with haemoproteus columbae through flies bites, injection with either infected salivary glands suspension or infected macerated lung tissue of c. livia revealed a high parasi ... | 1998 | 9617043 |
role of pseudolynchia canariensis in the transmission of haemoproteus turtur from the migrant streptopelia turtur to new bird hosts in egypt. | pseudolynchia canariensis flies offered the naturally infected migrant dove streptopelia turtur with haemoproteus turtur succeeded to induce weak infection in the raised streptopelia turtur only. intraperitoneal, intramuscular and subcutaneous injection of their salivary glands together with intraperitoneal injection of macerated lung and liver tissues of infected doves revealed the appearance of low and moderate grade parasitaemia in s. senegallus and the raised s. turtur. flies offered laborat ... | 1998 | 9617059 |
starvation induced hypothyroidism involves perturbations in thyroid superoxide-sod system in pigeons. | this study investigated the influence of starvation over seven days on avian thyroidal superoxide radical levels and superoxide dismutase activity profiles in the indian rock pigeon columba livia intermeida, in relation with iodine metabolism. the serum thyroid hormone profile was assayed to correlate the thyroidal redox status with the circulating thyroid hormone levels. the spin-trapping results suggest a role for thyroidal superoxide anion (o2.-) in causing a hypothyroid state in pigeons duri ... | 1998 | 9635131 |
[comparative investigations on inhalation anesthesia with isoflurane (forene) and sevoflurane (sevorane) in racing pigeons (columba livia gmel., 1789, var. domestica) and presentation of a reference anesthesia protocol for birds]. | a conventional inhalation anaesthesia using an isoflurane and sevoflurane-oxygen-nitrous oxide-mixture was performed in each six domestic pigeons (columbia livia gmel., 1789, var. domestica). over a period of 60 minutes routine anaesthetic monitoring including reflex score (12 reflexes, cloacal body temperature and pulse oximetry) was performed. for anaesthesia maintainance 4.0 +/- 0.3 vol. % sevoflurane compared to 2.0 +/- 0.2 vol. % isoflurane were used. the induction period using sevoflurane ... | 1998 | 9646418 |
identification of two y-box binding proteins that interact with the promoters of columbid annexin i genes. | two annexin i (anxi) genes, called cp35 and cp37, are expressed from the pigeon (columba livia) genome, but they are regulated differently at both the transcriptional and post-transcriptional levels. the proximal promoter elements of these two genes are very similar. a conserved sequence from the cp35 and cp37 promoters bound specifically with proteins present in cropsac cell extracts. this sequence of dna was used to screen a lambdagt11 cdna expression library. clones encoding two pigeon y-box ... | 1998 | 9651510 |
morphological and immunohistochemical considerations on the basal ganglia in pigeon (columba livia). | morphological and immunohistochemical studies carried out particularly around the level of the basal ganglia (bg) in birds, are reported and commented on. our results showed, on paraffin embedded avian bg, both the histological features and the immunohistochemical findings on immunofluorescence distribution of some neuropeptides (especially metenkephalin) in the striatal complex. by comparing our results of metenkephalin immunoreactivity (menkir) with the referred analogous ones of substance p ( ... | 1998 | 9652145 |
glutamatergic neurotransmission from the optic tectum to the contralateral nucleus rotundus in pigeons. | neuronal responses of 114 cells to electrical stimulation of the optic tectum were extracellularly recorded from the contralateral nucleus rotundus (nrt) in pigeons (columba livia), and the effects of two glutamatergic antagonists cnqx and cpp, as well as those of gaba, were examined on rotundal cells. the results show that tectal stimulation evokes excitation in neurons of the contralateral nrt and that the excitatory responses are blocked by microiontophoretically applied cnqx, cpp and gaba. i ... | 1998 | 9667809 |
pharmacokinetics and efficacy of amoxycillin in the treatment of an experimental streptococcus bovis infection in racing pigeons (columba livia). | the pharmacokinetics of amoxycillin in pigeons (columba livia) and the efficacy of amoxycillin treatment in pigeon streptococcosis, were investigated. after intravenous administration of 150 mg.kg-1 amoxycillin, the drug plasma concentration-time profile fitted an open two-compartment model. amoxycillin was quickly cleared from the circulation with a mean half-life of 66 min and showed a distribution volume of 0.9 l.kg-1. the absolute oral bioavailability of amoxycillin was 50.1%. a 5-day drinki ... | 1998 | 9691852 |
do female pigeons trade pair copulations for protection? | male pigeons, columba livia, employ intense mate guarding and frequent copulation apparently as strategies to ensure their paternity. the aim of this study was to investigate the benefits to females of mate guarding by males and frequent copulation. field observations showed that females initiated the majority of copulations and females that solicited copulations more frequently were guarded more closely by their partner. experimental removal of guarding male partners showed that: (1) unguarded, ... | 1998 | 9710482 |
expression of myosin heavy chain isoforms during development of domestic pigeon pectoralis muscle. | the pectoralis muscle of birds provides virtually all the power for the downstroke of the wing during flight. in adults it consists almost entirely of fog (fast-twitch oxidative-glycolytic) and/or fg (fast-twitch glycolytic) fiber types. the aims of this study are to contrast myhc (myosin heavy chain) transitions occurring within avian fg and fog fibers during development, and to test the hypothesis that the pectoralis matures before the acquisition of flight. pectoralis was obtained from pigeon ... | 1998 | 9712520 |
furadan sp50 induced haematological responses of blue-rock pigeon, columba livia gmelin. | | 1998 | 9724351 |
in vivo and in vitro sensitivity of trichomonas gallinae to some nitroimidazole drugs. | a study was carried out in order to establish the in vivo efficacy of two nitroimidazole drugs against the flagellate trichomonas gallinae. the results obtained showed a high proportion of therapeutic failures. thus, carnidazole and dimetridazole failed to eliminate infection in 13 of 17 and 20 of 21 racing pigeons, respectively. the in vitro susceptibility of four t. gallinae isolates to five nitroimidazolic drugs, that is, carnidazole, dimetridazole, metronidazole, ornidazole and ronidazole, w ... | 1998 | 9786623 |
in vivo strains in pigeon flight feather shafts: implications for structural design | to evaluate the safety factor for flight feather shafts, in vivo strains were recorded during free flight from the dorsal surface of a variety of flight feathers of captive pigeons (columba livia) using metal foil strain gauges. strains recorded while the birds flew at a slow speed (approximately 5-6 m s-1) were used to calculate functional stresses on the basis of published values for the elastic modulus of feather keratin. these stresses were then compared with measurements of the failure stre ... | 1998 | 9787125 |
vigilance states and body temperature during the circadian cycle in fed and fasted pigeons (columba livia). | fasting induces nocturnal hypothermia in pigeons. slow-wave sleep (sws) and paradoxical sleep (ps) are associated with reduced heat production in pigeons. the possibility that fasting-induced nocturnal hypothermia is related to increased sws and ps was examined by comparing body temperature (tb) and vigilance states when pigeons were fed and fasted. the results showed that when tb is decreasing near the beginning of the dark phase, the percentage of total recording time (%trt) spent in sws and p ... | 1998 | 9791092 |
[reaction of melanocytes in vertebrate retina to the exposure to constant magnetic field]. | the influence of a constant magnetic field (strain 40 ka/m) on retina pigmentary cells of grass frog (rana temporaria) and grey pigeon (columba livia) eyes was investigated. changes in the number and length of melanocytes appendixes were noticed accompanied by formation of thickenings in which melanosomes sized from 0.1 to 0.5 micron are moving. it is established that magnetic properties of eye retina pigmentary cells depend on the presence of fe3+ in melanin. a theoretical model of paramagnetic ... | 1998 | 9793181 |
how to stay cool in a hot desert--a lesson from the rock pigeon. | this review presents an overview of the puzzle called "cutaneous water evaporation (cwe) cooling mechanism" in birds. heat acclimation of the rock pigeon induces cellular modifications that affect the myocardium, cutaneous vasculature, and the epidermis, and hence enable the initiation of cwe. these cells are the targets for adrenergic signals that participate in the mechanism that controls the initiation and intensity of cwe. as a result the cardiac performance of the heat acclimated pigeon is ... | 1998 | 9793801 |
pigs in space: spatial memory and its susceptibility to interference. | this study provided basic information about spatial memory in the domestic pig, sus scrofa and examined how susceptible it is to disruption by environmental stimuli. eight male pigs were tested individually in a foraging arena. each day, they entered the arena to search for food randomly located in one of 10 enclosed areas (search trial). after finding and eating the food, they were removed from the arena for a retention interval, and then allowed back in to relocate the food in the same area as ... | 1997 | 9794774 |
in vivo pectoralis muscle force-length behavior during level flight in pigeons (columba livia) | for the first time, we report in vivo measurements of pectoralis muscle length change obtained using sonomicrometry combined with measurements of its force development via deltopectoral crest strain recordings of a bird in free flight. these measurements allow us to characterize the contractile behavior and mechanical power output of the pectoralis under dynamic conditions of slow level flight in pigeons columba livia. our recordings confirm that the pigeon pectoralis generates in vivo work loop ... | 1998 | 9817827 |
radiographic monitoring of the ossification of long bones in kori (ardeotis kori) and white-bellied (eupodotis senegalensis) bustards. | a serial radiographic study was conducted on eight kori bustard (ardeotis kori) and four white-bellied bustard (eupodotis senegalensis) chicks to determine the pattern of long bone development and to establish radiographic standards for assessing skeletal maturity. the ossification pattern, appearance of secondary ossification centres, and epiphyseal fusion of the long bones in kori and white-bellied bustards were similar to those in houbara bustards (chlamydotis undulata macqueenii), rufous-cre ... | 1998 | 9839896 |
bioaccumulation of manganese and its toxicity in feral pigeons (columba livia) exposed to manganese oxide dust (mn3o4). | manganese tetroxide (mn3o4) is a product from the combustion of methylcyclopentadienyl manganese tricarbonyl. exposure to high levels of manganese can lead to serious health effects especially to the central nervous and respiratory systems. very few studies on the effects of long-term low level exposure to mn3o4 have been reported. the present study was therefore conducted to examine the bioaccumulation and toxicity of manganese in various organs of feral pigeons (columba livia) when exposed to ... | 1998 | 9841807 |
trigeminal disynaptic circuit mediating corneal afferent input to m. depressor palpebrae inferioris motoneurons in the pigeon (columba livia). | corneal afferent projections to the trigeminal brainstem nuclear complex (tbnc) and associated structures, as determined by transganglionic transport of various tracers, were found to be predominantly concentrated in two distinct patches in the dorsolateral medulla at periobex levels. one was in the external cuneate nucleus, and the other was in the ventralmost part of the ophthalmic division of the tbnc. the projections of putative second-order neurons in these regions, as determined by injecti ... | 1999 | 9886038 |
influence of a melatonin implant on the free radical load in avian thyroid and its relation with thyroid hormonogenesis. | the primary aim of this study was to evaluate the effect of melatonin on the oxiradical load in avian thyroid. the superoxide free radicals have been spin trapped by epr spectroscopy in the thyroid gland of indian rock pigeon columbia livia following melatonin implantation for two weeks. melatonin implantation resulted in augmentation in the levels of superoxide radical in the thyroid gland of pigeons with a concomitant decrease in the levels of the total superoxide dismutase activity. this was ... | 1998 | 9891859 |
characteristics of slow and fast phases of the optocollic reflex (ocr) in head free pigeons (columba livia): influence of flight behaviour. | the effect of behavioural context on the properties of slow and fast phases of the horizontal optocollic reflex (ocr) were investigated in head free pigeons for two situations, i.e.: (i) animals were hung in a harness ('resting condition'); (ii) animals were additionally submitted to a frontal airflow that provoked a flight posture ('flying condition') [bilo and bilo (1983) j. comp. physiol., 153, 111]. a 'transient flight' was also provoked in the 'resting condition' by tapping the breastbone r ... | 1999 | 9987020 |
therapeutic effects of some antihaematozoal drugs against haemoproteus columbae in domestic pigeons. | three antihaematozoal drugs were tested for the treatment of pigeons naturally infected with haemoproteus columbae. butalex (buparvaquone) was found effective against the parasite either by using the recommended dose (r. d.) or the double (d. d.) dosis. the r. d. of berenil (diminazene aceturate) was not effective while the d. d. reduced the number of gametocytes circulating in the infected blood. triquine was found very toxic to the pigeons both the r. d. and the d. d. | 1999 | 10085582 |
streptomycin ototoxicity and hair cell regeneration in the adult pigeon utricle. | the purpose of this study was to develop a technique to investigate the regeneration of utricular hair cells in the adult pigeon (columba livia) following complete hair cell loss through administration of streptomycin. | 1999 | 10089957 |
efferent projections of the ectostriatum in the pigeon (columba livia). | the ectostriatum is a major visual component of the avian telencephalon. the core region of the ectostriatum (ec) receives visual input from the optic tectum through thalamic nuclei. in the present study, the efferent projections of the ectostriatum were investigated by using the anterograde tracers phaseolus vulgaris leucoagglutinin and biotinylated dextran amine. projection patterns resulting from these tracers were confirmed by the retrograde tracer cholera toxin subunit b. when anterograde t ... | 1999 | 10102499 |
staying in plastic containers interferes with the orientation of clock-shifted homing pigeons. | staying in plastic containers ventilated with natural air during transport and while waiting at the release site was found to affect the initial orientation of pigeons, columba livia f. domestica, that were exposed to a 6-h clock-shift. the deflection from the mean direction of controls was significantly smaller, and the mean vector length was significantly shorter, than that of clock-shifted pigeons transported in conventional wooden cages. this effect was most pronounced when the birds stayed ... | 1999 | 10196061 |
the social transmission of spatial information in homing pigeons. | we adapted a technique to explore the social transmission of spatial information in homing pigeons columba livia. five demonstrator pigeons were first trained to find a food goal within an indoor arena. this arena consisted of nine lidded cups laid out within a 12x12 grid on the floor. the task was to find the goal cup and flip the lid to obtain the food hidden within. once the demonstrators had reached criterion the experiment proper began. during stage 1 of the experiment, 10 target birds, whi ... | 1999 | 10196063 |
afferent and efferent connections of the caudolateral neostriatum in the pigeon (columba livia): a retro- and anterograde pathway tracing study. | the avian caudolateral neostriatum (ncl) was first identified on the basis of its dense dopaminergic innervation. this fact and data from lesion studies have led to the notion that ncl might be the avian equivalent of prefrontal cortex (pfc). a key feature of the pfc is the ability to integrate information from all modalities needed for the generation of motor plans. by using antero- and retrograde pathway tracing techniques, we investigated the organization of sensory afferents to the ncl and t ... | 1999 | 10213093 |
alpha-chloralose immobilization of rock doves in ohio. | to improve capture efficacy of rock doves (columba livia) in nuisance situations, we reevaluated the effectiveness of three dosages (60, 120 and 180 mg/kg) of alpha-chloralose (ac). responses to immobilization using 180 mg/kg ac also were compared in rock doves deprived of food for 16 hr and not food deprived. mean (+/- se) time to first effects (33 +/- 2 min) and mean time to capture (94 +/- 5 min) were significantly less for rock doves receiving 180 mg/kg than for rock doves receiving lower do ... | 1999 | 10231749 |
equal frequencies of recombination nodules in both sexes of the pigeon suggest a basic difference with eutherian mammals. | the total number of recombination nodules (rns) in the autosomal synaptonemal complexes (scs) is statistically equivalent in oocytes and spermatocytes from the domestic pigeon columba livia. the distribution on rns along the three longest autosomes is also equivalent in oocytes and spermatocytes. the numbers of rns show a linear relationship when plotted against sc length both in oocytes and spermatocytes. on the other hand, the zw pair shows a single and strictly localized rn near the synaptic ... | 1999 | 10231963 |
visual discrimination in the pigeon (columba livia): effects of selective lesions of the nucleus rotundus. | the nucleus rotundus is a large thalamic nucleus in birds and plays a critical role in many visual discrimination tasks. in order to test the hypothesis that there are functionally distinct subdivisions in the nucleus rotundus, effects of selective lesions of the nucleus were studied in pigeons. the birds were trained to discriminate between different types of stationary objects and between different directions of moving objects. multiple regression analyses revealed that lesions in the anterior ... | 1999 | 10321471 |
effects of food restriction on food avoidance and risk of acute poisoning of captive feral pigeons from fonofos-treated seeds | fonofos is a highly toxic insecticide to birds that, when used as a cereal seed treatment, has caused mortality of free-living feral pigeons (columba livia). pigeons kept individually under ad libitum feeding conditions in the laboratory do not suffer lethal poisoning because they develop a strong avoidance response to fonofos-treated seed, which restricts consumption to below lethal levels. two laboratory experiments were conducted to assess the role of avoidance in reducing the risk of acute p ... | 1999 | 10341049 |
shiga toxin-producing escherichia coli o157 in feedlot cattle and norwegian rats from a large-scale farm. | a total of 365 faecal samples from different categories of cattle, 12 samples of untreated slurry, 50 samples of fresh droppings of feral domestic pigeons, 20 samples of fresh droppings of domestic sparrows and stool samples of 19 synanthropic rodents were examined for the presence of escherichia coli by broth enrichment culture and a subsequent immunomagnetic separation. escherichia coli o157 was found in 72 (20%) bovine samples, six (50%) samples of untreated slurry and four (40%) of 10 rats ( ... | 1999 | 10389259 |
haemoproteus columbae in domestic pigeons in sebele, gaborone, botswana. | mature and immature stages of haemoproteus columbae gametocytes, an avian haemosporidian protozoan parasite were found in 75% of blood smears prepared from 30 healthy domestic pigeons in sebele location, gaborone, botswana. parenteral administration of an immuno-suppressive dose of dexamethasone, lowered the level of parasitaemia, the packed cell volume and the heterophil:lymphocyte ratio in the test pigeons. however, both the dexamethasone-treated and the control pigeons remained clinically nor ... | 1999 | 10396759 |
distribution and time course of hair cell regeneration in the pigeon utricle. | vestibular and cochlear regeneration following ototoxic insult from aminoglycoside antibiotics has been well documented, particularly in birds. in the present study, intraotic application of a 2 mg streptomycin paste was used to achieve complete vestibular hair cell destruction in pigeons (columba livia) while preserving regenerative ability. scanning electron microscopy was used to quantify hair cell density longitudinally during regeneration in three different utricular macula locations, inclu ... | 1999 | 10416861 |
shivering thermogenesis in leg and breast muscles of galliform chicks and nestlings of the domestic pigeon. | we studied the ontogeny of shivering thermogenesis in breast and leg muscles of precocial galliforms (domestic fowl, grey partridge, and japanese quail) and the altricial domestic pigeon using electromyography (emg) and indirect calorimetry. galliforms were able to increase heat production by shivering in leg muscles at the youngest age studied (1-2 d). pectorals contributed to heat production from days 7-10 onward, but in the partridge and especially in the fowl, shivering by the pectorals was ... | 1999 | 10438684 |
neurochemical evidence for at least two regional subdivisions within the homing pigeon (columba livia) caudolateral neostriatum. | the distributions of one neurotransmitter, two neurotransmitter-related substances, and five neuropeptides were examined within the homing pigeon caudolateral neostriatum (ncl). all eight neuroactive substances were found within a tyrosine hydroxylase (th)-dense region that defines the ncl. overall regional variation in the relative density of these substances suggested at least two neurochemically distinct portions of ncl. dorsal ncl contained relatively dense staining for th, choline acetyltra ... | 1999 | 10441234 |
a scanning and transmission electron microscopy study of the parabronchial unit in quail (coturnix coturnix) and town pigeons (columba livia). | a combined scanning electron (sem) and transmission electron microscopy (tem) investigation was undertaken to gain insight into the complex structural pattern of the atrial compartment and the gas exchange tissue of parabronchial units in quail and town pigeons. the aim was also to depict the changes taking place in the parabronchial unit in the late prehatching and early posthatching periods in quail. the standard sem and tem investigation was carried out in 13 mature quail and 8 town pigeons. ... | 1999 | 10483882 |
pharmacology of sensory gating in the ascending auditory system of the pigeon (columba livia). | whether the underlying neurochemical basis of sensori(motor) gating is exclusively the result of mammalian brain evolution is not known. | 1999 | 10494576 |
preserved negative patterning and impaired spatial learning in pigeons (columba livia) with lesions of the hippocampus. | pigeons (columba livia) with bilateral electrolytic lesions of the hippocampus and area parahippocampalis were compared with control pigeons on 2 tasks: negative patterning and delayed spatial alternation. negative patterning demands configural stimulus representations for its successful solution. the only effect of hippocampal lesions on this task was an increased response rate to the rewarded stimuli. on the delayed spatial alternation task, hippocampal birds showed deficits relative to contro ... | 1999 | 10495077 |
cardiovascular and thermoregulatory responses to vasotocin and angiotensin ii in the pigeon. | the cardiovascular and thermoregulatory effects of intrahypothalamically (preoptic/anterior hypothalamus) and intravenously injected arginine vasotocin (avt) and [val5]angiotensin ii (ang ii) were measured at 2 degrees c in the pigeon (columba livia). in addition, the effects of intrahypothalamic and intravenous injections of avt on respiratory rates were measured at 10-15 degrees c. intrahypothalamic and intravenous avt (500 ng and 20 micrograms/kg, respectively) reduced shivering and body temp ... | 1999 | 10501020 |
projections of purkinje cells in the translation and rotation zones of the vestibulocerebellum in pigeon (columba livia). | previous electrophysiological studies have shown that the pigeon vestibulocerebellum (ventral uvula, nodulus, and flocculus) can be divided into two parasagittal zones based on responses to optic flow stimuli. the medial zone (ventral uvula and nodulus) responds best to optic flow resulting from self-translation, whereas the lateral zone (flocculus) responds best to optic flow resulting from self-rotation. in this study we investigated the projections of the purkinje cells in the translation and ... | 1999 | 10502253 |
reciprocal natural selection on host-parasite phenotypes. | coevolution is evolution in one species in response to selection imposed by a second species, followed by evolution in the second species in response to reciprocal selection imposed by the first species. although reciprocal selection is a prerequisite of coevolution, it has seldom been documented in natural populations. we examined the feasibility of reciprocal selection in a simple host-parasite system consisting of feral pigeons (columba livia) and their ischnoceran feather lice (phthiraptera: ... | 1999 | 10506542 |
the molecular genetics of red and green color vision in mammals. | to elucidate the molecular mechanisms of red-green color vision in mammals, we have cloned and sequenced the red and green opsin cdnas of cat (felis catus), horse (equus caballus), gray squirrel (sciurus carolinensis), white-tailed deer (odocoileus virginianus), and guinea pig (cavia porcellus). these opsins were expressed in cos1 cells and reconstituted with 11-cis-retinal. the purified visual pigments of the cat, horse, squirrel, deer, and guinea pig have lambdamax values at 553, 545, 532, 531 ... | 1999 | 10511567 |
[the characteristics of the morphological structure of the endbrain in the hooded crow (corvus corone cornix l.) and in the rock dove (columba livia) in relation to their development of elementary reasoning activities]. | the number of neurons in the endbrain [correction of forebrain] of two avian species--carrion crows and rock pigeons--was assessed. it was shown that the higher development of reasoning activity of crows is associated with greater number of cells in evolutionary new fields of hyperstriatum and greater number of cell complexes than in pigeons. | 1999 | 10512030 |
heat stress induces ultrastructural changes in cutaneous capillary wall of heat-acclimated rock pigeon. | in heat-acclimated rock pigeons, cutaneous water evaporation is the major cooling mechanism when exposed at rest to an extremely hot environment of 50-60 degrees c. this evaporative pathway is also activated in room temperature by a beta-adrenergic antagonist (propranolol) or an alpha-adrenergic agonist (clonidine) and inhibited by a beta-adrenergic agonist (isoproterenol). in contrast, neither heat exposure nor drug administration activates cutaneous evaporation in cold-acclimated pigeons. to e ... | 1999 | 10516233 |
feral pigeons as carriers of cryptococcus laurentii, cryptococcus uniguttulatus and debaryomyces hansenii. | we collected fresh droppings and cloaca samples from feral pigeons columba livia in the southern swedish city of malmö, and isolated the following fungi: debaryomyces hansenii var. hansenii, cryptococcus laurentii and cryptococcus uniguttulatus. the first two species are known to be pathogenic to humans. no strains of cryptococcus neoformans var. neoformans were found. our results indicate that feral pigeons can be carriers of medically significant fungi other than cryptococcus neoformans var. n ... | 1999 | 10520162 |
reversible mechanical fixation of eye position in awake head-restrained pigeons (columba livia). | here we describe a method to fix gaze positions and to significantly reduce saccadic oscillations in pigeons. the procedure consists of a mechanical immobilization of the eye through the use of an electromagnet that exerts a radial force upon a small metal rectangle glued to the dorsal part of the eye. the method can be used in avian visual neurophysiology in order to hold the eye immobilized for periods of time, long enough to map the properties of visual receptive fields and investigate the po ... | 1999 | 10522825 |
morphological study of the vas deferens of the pigeon (columba livia). | a morphological study of the vas deferens of the pigeon was carried out in order to determine the electronmicroscopic features of its epithelial lining, and the expression of pancytokeratins. the results showed that the epithelium is columnar pseudostratified and consists of non-ciliated (principal) cells and basal cells. presence of a predominantly granular endoplasmic reticulum, mitochondria and well-developed golgi complexes bearing vesicles on their cis/trans surfaces were observed. in addit ... | 1999 | 10575825 |
morphologic study of the efferent ductules of the pigeon (columba livia). | the efferent ductules of the pigeon are localized in the epididymal region and are topographically divided into proximal and distal, both portions being lined with stereociliated pseudostratified epithelium. transmission electron microscopy shows five distinct cell types: light, dark, and angular non-ciliated cells with possible apocrine secretory role cells and halo cells, possibly intraepithelial leucocytes. the proximal efferent ductules have the widest diameter among all ductules in the epid ... | 1999 | 10580263 |
genetic analyses of visual pigments of the pigeon (columba livia). | we isolated five classes of retinal opsin genes rh1(cl), rh2(cl), sws1(cl), sws2(cl), and lws(cl) from the pigeon; these encode rh1(cl), rh2(cl), sws1(cl), sws2(cl), and lws(cl) opsins, respectively. upon binding to 11-cis-retinal, these opsins regenerate the corresponding photosensitive molecules, visual pigments. the absorbance spectra of visual pigments have a broad bell shape with the peak, being called lambdamax. previously, the sws1(cl) opsin cdna was isolated from the pigeon retinal rna, ... | 1999 | 10581289 |
experimental inoculation of domestic pigeons (columbia livia) and zebra finches (poephila guttata) with neospora caninum tachyzoites. | dogs are a definitive host of neospora caninum and cattle are intermediate hosts. alternative life-cycles have not been investigated. foxes are frequently seropositive, but may not commonly prey upon cattle; therefore, other intermediate hosts may exist that are frequent prey of foxes. three domestic pigeons (columbia livia) and three zebra finches (poephila guttata) were inoculated with n. caninum tachyzoites, to determine if they could serve as intermediate hosts. tissue culture, pcr, serology ... | 1999 | 10608438 |
monocular deprivation alters the direction of functional and morphological asymmetries in the pigeon's (columba livia) visual system. | one-day-old pigeons (columba livia) were monocularly deprived by occluding the left or the right eye for 10 days. up to 3 years later, degree and direction of functional and morphological asymmetries of deprived and control pigeons were analyzed. in control pigeons, the usual right-eye superiority was obtained in a visual discrimination task. in left-eye deprived pigeons, this behavioral asymmetry was strengthened, whereas the direction of lateralization was reversed in right-eye deprived birds. ... | 1999 | 10636304 |
a morphological study of the cochlear nuclei of the pigeon (columba livia). | the pigeon cochlear nucleus angularis (na) and nucleus magnocellularis (nm) were analyzed with golgi and nissl techniques. na was divided into a medial nam and na proper, which could be subdivided further into an intermediate nai and lateral nal. nam contained a mostly homogeneous population of a unique multipolar cell type with very short dendrites and large somatic spines. na proper contained four cell types: large, medium, and small multipolars, and medium bipolar. the medium multipolar cells ... | 1999 | 10640788 |
kinematics and mechanics of ground take-off in the starling sturnis vulgaris and the quail coturnix coturnix. | the mechanics of avian take-off are central to hypotheses about flight evolution, but have not been quantified in terms of whole-body movements for any species. in this study, i use a combination of high-speed video analysis and force plate recording to measure the kinematics and mechanics of ground take-off in the european starling sturnis vulgaris and the european migratory quail coturnix coturnix. counter to hypotheses based on the habits and morphology of each species, s. vulgaris and c. cot ... | 2000 | 10648214 |
spatiotemporal profile of synaptic activation produced by the electrical and visual stimulation of retinal inputs to the optic tectum: a current source density analysis in the pigeon (columba livia). | the optic tectum of the pigeon is a highly organized, multilayered structure that receives a massive polystratified afference of at least five different populations of retinal ganglion cells and gives rise to various anatomically segregated efferent systems. the synaptic organization of retino-tectal circuitry is, at present, mostly unknown. to investigate the spatiotemporal profile of synaptic activation produced by differential (electrical and visual) stimulation of the retinal inputs, we perf ... | 2000 | 10651859 |
the pigeon tick (argas reflexus): its biology, ecology, and epidemiological aspects. | the european pigeon tick, argas reflexus (f.), is in central europe predominantly an urban pest parasitizing wild and domesticated pigeons, columba livia. under certain circumstances, however, it also bites humans, occasionally causing an ige-mediated type-i allergy. control of a. reflexus is very difficult because of a number of remarkable morphological, physiological, and behavioural features of the tick. the present study aimed at elucidating the distribution and the frequency of occurrence o ... | 1999 | 10652727 |
head-bobbing in pigeons: how stable is the hold phase? | the head movement of a walking pigeon columba livia is characterized by two alternating phases, a thrust phase and a hold phase. while the head is rapidly thrust forward during the thrust phase, it has been shown repeatedly that it remains virtually motionless with respect to translation along a horizontal axis (roll axis) during the hold phase. it has been shown that the stabilization during the hold phase is under visual control. this has led to the view that the pigeon's head-bobbing is an op ... | 2000 | 10667977 |
a comparative golgi study of chicken (gallus domesticus) and homing pigeon (columba livia) hippocampus. | neurons and fibres in the chick and homing pigeon hippocampus were described following golgi impregnation. two principal classes of neurons were distinguished: projection neurons with distant projecting axons and spiny dendrites, and local circuit neurons. in the homing pigeon and chicken hippocampus there are three types of projection neurons: pyramidal, pyramidal-like and multipolar. the pyramidal and pyramidal-like neurons are only found in the central 'pyramidal' layer of the hippocampus whe ... | 2000 | 10672361 |
pigeon paramyxovirus-1 (p-group) as the cause of severe outbreaks in fancy columba livia in saudi arabia. | an avian paramyxovirus-1, which was previously isolated from ailing fancy columba livia in saudi arabia, was characterized in this study using monoclonal antibodies (mabs). the results indicate that although the virus belongs to the pigeon paramyxovirus-1 (ppmv-1) group 'p' still it shows some variation in its binding pattern to the mabs. | 1999 | 10676146 |
evidence for physiological asymmetries in the intertectal connections of the pigeon (columba livia) and their potential role in brain lateralisation. | in pigeons, visual object processing is lateralised with a dominance of the left tectofugal system. to test the hypothesis, that avian visual lateralisation may arise, at least in part, from asymmetric interhemispheric inhibition, the intertectal modulation was quantified in 19 pigeons. field potentials were recorded from intratectal electrodes in response to a stroboscope flash to the contralateral eye. electrical stimulation of the contralateral tectum changed these flash-evoked potentials. th ... | 2000 | 10678768 |
role of peridomestic birds in the transmission of st. louis encephalitis virus in southern california. | in response to the 1984 st. louis encephalitis (sle) epidemic in the los angeles basin of southern california (usa), an investigative program was initiated to evaluate the interactive components of the sle virus transmission cycle. from 1987 through 1996 (10 yr), 52,589 birds were bled and their sera tested for sle and western equine encephalomyelitis (wee) virus antibodies by the hemagglutination inhibition (hai) test. eighty-three percent of the birds tested were house finches (carpodacus mexi ... | 2000 | 10682741 |
development and characterization of expressed sequence tags for the turkey (meleagris gallopavo) genome and comparative sequence analysis with other birds. | twenty-one randomly selected clones from a turkey (meleagris gallopavo) pituitary complementary dna (cdna) library were sequenced to develop expressed sequence tags (ests) for this economically important avian species whose genome is among the least understood. primers specific for the ests were used to produce amplicons from the genomic dna of turkey, chicken (gallus gallus), guinea fowl (numidia meleagris), pigeon (columba domestica), and quail (corturnix japonica). the amplicons were sequence ... | 2000 | 10690363 |
further experiments on the relationship between hippocampus and orientation following phase-shift in homing pigeons. | following a clock- or phase-shift of the light dark cycle, hippocampal lesioned pigeons (columba livia) consistently display a larger deviation in vanishing bearings away from the homeward direction compared to intact birds; an effect never seen in unshifted birds. in experiment 1, control and hippocampal lesioned pigeons oriented similarly after being held 1 week under artificial lighting in the absence of a phase-shift. housing under artificial light by itself does not result in between group ... | 2000 | 10701659 |
polymorphic dna microsatellites in the domestic pigeon, columba livia var. domestica. | | 2000 | 10736035 |
role of basal ganglia and ectostriatum in the context-dependent properties of the optocollic reflex (ocr) in the pigeon (columba livia): a lesion study. | the possible participation of basal ganglia and associated structures [dorsal striato-pallidum, nucleus spiriformis lateralis (spl), ectostriatum] in the elaboration of the optocollic reflex (ocr) was investigated by making bilateral chemical lesions (ibotenic acid). previous data have shown that both the slow and fast phases of the ocr are dependent on the behavioural context. the slow phase velocity (spv) and the peak velocity of fast phases obtained in non-flying pigeons ('resting condition') ... | 2000 | 10762337 |
the role of beta-adrenergic receptors in the cutaneous water evaporation mechanism in the heat-acclimated pigeon (columba livia). | the effects of selective and non-selective beta-adrenergic agents on cutaneous water evaporation (cwe) were studied in hand-reared rock pigeons (columba livia). cwe was measured by the vapor diffusive resistance method, using a transient porometer. intramuscular and subcutaneous injections of a non-selective beta-adrenergic antagonist (propranolol) or a selective beta(2)-adrenergic antagonist (ici-118551) to heat-acclimated (hac) pigeons at ambient temperature (t(a)) of 24 degrees c resulted in ... | 2000 | 10779732 |
stimulus repetition effects on texture-based visual search by pigeons. | four experiments investigated the effects of within-session stimulus repetition on texture discrimination. six pigeons (columba livia) searched for a contrasting target region (color or shape) randomly embedded within a larger distractor region for food reinforcement. experiment 1 found that repeating features of the distractors, but not those of the target, across trials increased the accuracy of target localization relative to baseline. experiment 2 found that subsequently switching the identi ... | 2000 | 10782436 |
the functional morphology of the avian flight muscle m. coracobrachialis posterior. | the extensive range of movement of the avian glenohumeral joint makes functional interpretation of any muscle that crosses the joint difficult. multiple functional roles for the m. coracobrachialis posterior (cbp), an architecturally complex muscle that lies deep to the m. pectoralis, have been assigned on the basis of its anatomical position. the mechanical properties, neuromotor pattern during flight and the biochemical properties of the cbp in pigeons (columba livia) were studied by in situ l ... | 2000 | 10804166 |
helminth parasites of domestic pigeons (columba livia domestica) in sebele, gaborone, botswana. | twelve adult domestic pigeons from sebele, gaborone, botswana, were examined for the presence of helminth parasites. the cestode genus raillietina and two species of nematodes, dispharynx spiralis and ascaridia columbae were recovered. most pigeons (75 %) were infected with raillietina spp. often in concurrence with a. columbae. | 2000 | 10843326 |
fracture healing after stabilization with intramedullary xenograft cortical bone pins: a study in pigeons. | to investigate the effectiveness of intramedullary xenograft cortical bone pins compared with stainless steel kirschner wire for the repair of a standardized avian humeral fracture. | 2000 | 10871225 |
mechanisms of the interaction of the angular and linear components of the horizontal vestibulo-ocular reflex in the pigeon. | intact pigeons (columba livia, n = 30) were rotated in a horizontal plane in the dark at different orientations relative to the axis of rotation. a total of 24 birds showed different directions of changes in the duration of contrarotatory nystamus (on transition from central rotation to eccentric), along with displacement of the otolith membranes in both the frontal and sagittal planes. these pigeons showed a direct relationship between changes in the duration of the primary phase of nystagmus a ... | 2000 | 10872727 |
spinomedullary pathways in the pigeon (columba livia): differential involvement of lamina i cells. | the lamina i (marginal zone) of the spinal cord dorsal horn is an important site for pain processing. in mammals, lamina i neurons have been shown to constitute a heterogeneous population made up of four morphological groups with particular neurochemical nature, supraspinal connection patterns, and nociceptive response properties. in order to obtain a comparative view of the mechanisms of nociceptive processing, the analysis of the structural morphology and supraspinal connectivity of lamina i n ... | 2000 | 10880993 |
partial experience with the arc of the sun is sufficient for all-day sun compass orientation in homing pigeons, columba livia. | the ability of animals to learn to use the sun for orientation has been explored in numerous species. in birds, there is conflicting evidence about the experience needed for sun compass orientation to develop. the prevailing hypothesis is that birds need entire daytime exposure to the arc of the sun to use the sun as an orientation cue. however, there is also some evidence indicating that, even with limited exposure to the arc of the sun, birds, like insects, can use the sun to orient at any tim ... | 2000 | 10887072 |
summation of symbols by pigeons (columba livia): the importance of number and mass of reward items. | in each of 3 experiments, different sets of 4 pigeons (columba livia) were trained to discriminate between 2 visual symbols that covered wells containing food items that varied in number, mass, or both. in experiment 1, the symbols were associated with 0, 1, 3, 5, 7, or 9 pieces of grain reward. the pigeons learned to choose the symbol corresponding to the larger reward, and on summation tests, they chose the pair of symbols that summed to the larger total reward. when number of food pellets was ... | 2000 | 10890587 |
circadian regulation of visually evoked potentials in the domestic pigeon, columba livia. | the avian circadian and visual systems are integrally related and together influence many aspects of birds' behavior and physiology. certainly, light cycles and their visual perception are the major zeitgebers for circadian rhythms, but do circadian rhythms affect vision? to assess whether visual function is regulated on a circadian basis, flash-evoked electroretinograms (ergs) and vision-evoked potentials (veps) from the optic tectum (teo) were recorded simultaneously in domestic pigeons at dif ... | 2000 | 10942263 |
inspiratory aerodynamic valving in the avian lung: functional morphology of the extrapulmonary primary bronchus. | the form, geometry and epithelial morphology of the extrapulmonary primary bronchi (eppb) of the domestic fowl (gallus gallus var. domesticus) and the rock dove (columba livia) were studied microscopically and by three-dimensional computer reconstruction to determine the structural features that may be involved in the rectification of the inspired air past the openings of the medioventral secondary bronchi (mvsb), i.e. the inspiratory aerodynamic valving (iav). in both species, the eppb were int ... | 2000 | 10952884 |