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PubMed1993

[Epizootiology and pathogenesis of avian mycobacteriosis in the house sparrow (Passer domesticus) and tree sparrow (Passer montanus)].

The occurrence and extension of avian mycobacteriosis in house-sparrows (P. domesticus) and mountain-sparrows (P. montanus) have been followed under different epidemiological conditions. Out of 2.929 totally examined house-sparrow pathological changes of tuberculosis were found in 3 (0.10%) animals and in 14 (0.48%) animals the mycobacteria were isolated. By an examination of 544 mountain-sparrow the mycobacteria in 12 (2.20%) cases and in 1 case were isolated and the mycobacteria were found in the intestinal contents. Out of 11 different locations the mycobacteria were found only in places where a contact between sparrows and poultry contaminated by TBC was possible. In some cases the sparrow could be a source of mycobacteria for cattle as well. Simultaneously, the occurrence of TBC in sparrows out of cattle stables correlated with high incidence of avian tuberculin reactions in cattle stabled there. The sparrow could be here not only the source but also an indicator of mycobacteria environment infection. All isolated strains of mycobacteria were virulent for poultry. In experimental infections there was proven a high sensitivity of both species of sparrows to M. avium. After intramuscular infection of M. avium suspension the histological changes in liver have been observed after 12 days, the microscopic changes after 21 days and miliary TBC after 35 days. Peroral infection by food contaminated by TBC poultry livers caused TBC changes in liver and spleen with clinical symptoms and death after 91 days. After free contact between TBC poultry and healthy sparrows the tuberculous changes of parenchymatous organs in sparrows were found after 180 days. There was no difference in sensitivity between the house-sparrow and mountain-sparrow. The transfer of M. avium from TBC-infected sparrows to pigs and poultry was successful. After 45 days of join contact among TBC sparrows, healthy pigs and poultry in stables and after further stay of pigs and poultry in contaminated surroundings there was found an allergy to tuberculin after 65 or 178 days, respectively. Simultaneously, the TBC liver and spleen in poultry were found. The house-sparrow and mountain-sparrow are very sensitive to the M. avium infections. The occurrence and extension of TBC infections in sparrows depends first of all on the possibility of contacts with TBC-infected poultry. Infected sparrows can be an important source of M. avium for other species of animals.

Animals↗
PubMed1999

Song development by chipping sparrows and field sparrows.

When, where and from whom young songbirds learn their songs have been controversial issues in the study of song development. We chose to study some of these issues in two migratory and closely related songbirds, the chipping sparrow, Spizella passerina, and field sparrow, Spizella pusilla. Nestlings of both species were collected in western Massachusetts and hand-reared in the laboratory. There, juveniles were placed in separate cages and assigned to one of three rooms; in each room were eight young chipping sparrows, eight young field sparrows and two adult tutors of each species, arranged so that most of the young males were adjacent to adult tutors of the same species. During mid-winter, adult tutors were moved from one room to another, so that the young birds heard different song types from different tutors during their hatching year and the following spring. From spectral analysis of our extensive tape recordings, we found that most juvenile males imitated the songs of their hatching-year tutors but then gradually modified their songs to match more closely either their adult tutors or other pupils the next spring. One chipping and one field sparrow clearly imitated a new song syllable from a spring live tutor; that is, these yearling males learned songs by 'instruction'. Other sparrows improvised extensively, and one chipping sparrow learned a field sparrow's song syllable. Our results reveal great individual variation in how songs are developed, and we expect similar flexibility among birds in nature. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1990

On the recovery of photosensitivity in two passerine species, American tree sparrows (Spizella arborea) and Harris' sparrows (Zonotrichia querula).

To test the hypothesis that a spontaneous increase in plasma luteinizing hormone (LH) signals recovery of photosensitivity in castrated passerine birds, LH concentrations were measured weekly in intact and in castrated photorefractory tree sparrows and Harris' sparrows transferred to short days. After 7 weeks on short days (Experiment 1) or after 1, 3, 5, 7, and 10 weeks (Experiment 2) were challenged with long days (1 week) to determine if photosensitivity had been restored. As evidenced by a significant LH response to photostimulation, tree sparrows had regained at least partial photosensitivity after 7 weeks on short days. However, during exposure to short days, plasma LH concentrations in castrated males did not differ from those in intact males, and plasma LH concentrations in intact or castrated males did not vary with time. The first indication that photosensitivity had been partially restored in Harris' sparrows came after 7 weeks on short days, when castrated males responded to photostimulation with a fourfold elevation in plasma LH concentration. However, before week 7 and through week 10, LH concentrations remained suppressed in both intact and castrated males retained on short days. These data show that recovery of photosensitivity in castrated tree sparrows and Harris' sparrows held on short days is not signaled by a spontaneous elevation in plasma LH concentration, and that plasma LH concentrations in acutely photosensitive intact male tree sparrows and Harris' sparrows held on short days are not suppressed because of gonadal negative feedback.

Animals↗
PubMed2000

Detection of thermophilic Campylobacter from sparrows by multiplex PCR: the role of sparrows as a source of contamination of broilers with Campylobacter.

The best combination of primers and the annealing temperature of multiplex PCR for Campylobacter jejuni, Campylobacter coli, and Campylobacter lari were examined. The multiplex PCR was able to detect type strains of the three species. All results of identification of wild strains (30 strains of C. jejuni, 20 strains of C. coli, and 4 strains of C. lari) by the multiplex PCR coincided with those of the conventional biochemical identification tests, suggesting that the multiplex PCR can simultaneously differentiate C. jejuni, C. coli, and C. lari from wild strains of campylobacters easily and rapidly. Campylobacters were detected from sparrow feces by the multiplex PCR and antimicrobial sensitivities of the strains were determined to discuss the role of sparrows in contamination of broilers with C. jejuni. Three out of 13 strains of C. jejuni isolated from sparrow feces showed quinolone resistance. From the frequent use of quinolones for treatment of industrial animals like chickens, pigs, and cows, the three strains of quinolone-resistant C. jejuni in sparrows must have been originated from those industrial animals. Sparrows that have quinolone-resistant C. jejuni were considered to have contacted with industrial animals or thier feed. It may be presumed, on the contrary, that C. jejuni in sparrows could be a potential source of contamination of broilers.

Animals↗
PubMedDate not supplied

Antibodies to alphavirus, flavivirus, and bunyavirus arboviruses in house sparrows (Passer domesticus) and tree sparrows (P. montanus) in Poland.

Sparrows from central Poland were examined by a hemagglutination-inhibition test (titer > or = 20) for the presence of antibodies to arboviruses, between 1995 and 1996. In house sparrows (Passer domesticus) (n = 179), antibodies to Sindbis, West Nile, tick-borne encephalitis, Tahyna, and Calovo viruses were detected at seroprevalences of 1.1%, 2.8%, 1.1%, 2.8%, and 1.1%, respectively. In tree sparrows (P. montanus) (n = 33), antibodies to the Sindbis, West Nile, and Tahyna viruses were detected at seroprevalences of 9.1%, 12.1%, and 3.0%, respectively.

Alphavirus↗
PubMed2003

Gonadotropin-inhibitory peptide in song sparrows (Melospiza melodia) in different reproductive conditions, and in house sparrows (Passer domesticus) relative to chicken-gonadotropin-releasing hormone.

Gonadotropin-releasing hormone (GnRH) regulates reproduction in all vertebrates. Until recently, an antagonistic neuropeptide for gonadotropin was unknown. The discovery of an RFamide peptide in quail that inhibits gonadotropin release in vitro raised the possibility of direct hypothalamic inhibition of gonadotropin release. This peptide has now been named gonadotropin-inhibitory hormone (GnIH). We investigated GnIH presence in the hypothalamus of two seasonally breeding songbird species, house sparrows (Passer domesticus) and song sparrows (Melospiza melodia). Using immunocytochemistry (ICC), GnIH-containing neurones were localized in both species in the paraventricular nucleus, with GnIH-containing fibres visible in multiple brain locations, including the median eminence and brainstem. Double-label ICC with light microscopy and fluorescent ICC with confocal microscopy indicate a high probability of colocalization of GnIH with GnRH neurones and fibres within the avian brain. It is plausible that GnIH could be acting at the level of the hypothalamus to regulate gonadotropin release as well as at the pituitary gland. In a photoperiod manipulation experiment, GnIH-containing neurones were larger in birds at the termination of the breeding season than at other times, consistent with a role for this neuropeptide in the regulation of seasonal breeding. We have yet to elucidate the dynamics of GnIH synthesis and release at different times of year, but the data imply temporal regulation of this peptide. In summary, GnIH has the potential to regulate gonadotropin release at more than one level, and its distribution is suggestive of multiple regulatory functions in the central nervous system.

Animals↗
PubMed2004

Gonadotropin-inhibitory hormone in Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii): cDNA identification, transcript localization and functional effects in laboratory and field experiments.

The neuropeptide control of gonadotropin secretion is primarily through the stimulatory action of the hypothalamic decapeptide, GnRH. We recently identified a novel hypothalamic dodecapeptide with a C-terminal LeuPro-Leu-Arg-Phe-NH2 sequence in the domestic bird, Japanese quail (Coturnix japonica). This novel peptide inhibited gonadotropin release in vitro from the quail anterior pituitary; thus it was named gonadotropin-inhibitory hormone (GnIH). GnIH may be an important factor regulating reproductive activity not only in domesticated birds but also in wild, seasonally breeding birds. Thus, we tested synthetic quail GnIH in seasonally breeding wild bird species. In an in vivo experiment, chicken gonadotropin-releasing hormone-I (cGnRH-I) alone or a cGnRH-I/quail GnIH cocktail was injected i.v. into non-breeding song sparrows (Melospiza melodia). Quail GnIH rapidly (within 2 min) attenuated the GnRH-induced rise in plasma LH. Furthermore, we tested the effects of quail GnIH in castrated, photostimulated Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii), using quail GnIH or saline for injection. Again, quail GnIH rapidly reduced plasma LH (within 3 min) compared with controls. To characterize fully the action of GnIH in wild birds, the identification of their endogenous GnIH is essential. Therefore, in the present study a cDNA encoding GnIH in the brain of Gambel's white-crowned sparrow was cloned by a combination of 3' and 5' rapid amplification of cDNA ends and compared with the quail GnIH cDNA previously identified. The deduced sparrow GnIH precursor consisted of 173 amino acid residues, encoding one sparrow GnIH and two sparrow GnIH-related peptides (sparrow GnIH-RP-1 and GnIH-RP-2) that included Leu-Pro-Xaa-Arg-Phe-NH2 (Xaa=Leu or Gln) at their C-termini. All these peptide sequences were flanked by a glycine C-terminal amidation signal and a single basic amino acid on each end as an endoproteolytic site. Although the homology of sparrow and quail GnIH precursors was approximately 66%, the C-terminal structures of GnIH, GnIH-RP-1 and GnIH-RP-2 were all identical in two species. In situ hybridization revealed the cellular localization of sparrow GnIH mRNA in the paraventricular nucleus (PVN) of the hypothalamus. Immunohistochemical analysis also showed that sparrow GnIH-like immunoreactive cell bodies and terminals were localized in the PVN and median eminence respectively. Thus, only the sparrow PVN expresses GnIH, which appears to be a hypothalamic inhibitory factor for LH release, as evident from our field injections of GnIH into free-living breeding white-crowned sparrows. Sparrow GnIH rapidly (within 2 min) reduced plasma LH when injected into free-living Gambel's white-crowned sparrows on their breeding grounds in northern Alaska. Taken together, our results indicate that, despite amino acid sequence differences, quail GnIH and sparrow GnIH have similar inhibitory effects on the reproductive axis in wild sparrow species. Thus, GnIH appears to be a modulator of gonadotropin release.

Animals↗
PubMed1987

Song syllable discrimination by song sparrows (Melospiza melodia).

A habituation test paradigm was used to examine the responses of free-living territorial adult male song sparrows (Melospiza melodia) to a range of synthetic songs. The three-phrased test songs differed from one another in having either conspecific or heterospecific (swamp sparrow, M. georgiana) syllables, or silence, in the second phrase. Subjects were exposed to repeated presentations of one song type until their approach distance to a loudspeaker increased. In one experiment, birds were habituated with a song consisting of three phrases of song sparrow syllables and then tested for generalization to either novel song sparrow syllables in the second phrase, swamp sparrow syllables, or silence. Birds discriminated between song sparrow syllables on two response measures, and between song sparrow and swamp sparrow syllables on one measure. In a second experiment, after habituation to a song with swamp sparrow syllables in the second phrase, birds did not generalize to novel song sparrow syllables, but they did generalize to novel swamp sparrow syllables. Thus song sparrows make finer distinctions among conspecific syllable variants than with alien syllables. The results further suggest that subtle species-specific differences in note structure within syllables are discriminated by song sparrows and potentially provide an adequate basis for individual recognition by song.

Animals↗
PubMed2000

Renal anatomy in sparrows from different environments.

The renal anatomy of three species of sparrows, two from mesic areas, the House Sparrow (Passer domesticus) and Song Sparrow (Melospiza melodia), and one salt marsh species, the Savannah Sparrow (Passerculus sandwichensis) was examined. Electron microscopy was used to describe the ultrastructure of the nephron. In addition, stereology was used to quantify the volumes of cortex, medulla, and major vasculature of the kidneys, and the volumes and surface areas occupied by individual nephron components. There appeared to be no differences in the ultrastructural anatomy of the nephrons among the sparrows. Proximal tubules contained both narrow and wide intercellular spaces filled with interdigitations of the basolateral membrane. The thin limbs of Henle contained very wide intercellular spaces which were absent in the thick limbs of Henle. The distal tubule cells contained short, apical microvilli and infoldings of the basolateral membrane. In cross section, the medullary cones of all birds display an outer ring of thick limbs of Henle which surround an inner ring of collecting ducts, which in turn surround a central core of thin limbs of Henle. The Savannah Sparrow has a significantly higher volume of medulla compared to the two more mesic species. Within the cortex, the Savannah Sparrow also has a significantly higher volume of proximal tubules but a significantly lower volume of distal tubules than the other species. Within the medulla, the Savannah Sparrow has a significantly higher volume and surface area of capillaries, and a significantly higher surface area of thick limbs of Henle and collecting ducts than the mesic species. These data suggest that the salt marsh Savannah Sparrow has the renal morphology necessary to produce a more highly concentrated urine than the mesic zone species.

Animals↗
PubMed2004

The effect of flight, fasting and p,p'-DDT on thyroid hormones and corticosterone in Gambel's white-crowned sparrow, Zonotrichia leucophrys gambelli.

This study examined the effects of p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), fasting and flight on thyroid hormones and corticosterone in Gambel's White-crowned Sparrows (Zonotrichia leucophrys gambelli). Female sparrows were dosed daily with either 5 mg p,p'-DDT per kg body mass or corn oil vehicle over 3 days. On the fifth day the sparrows were divided into 3 groups: (1) unstressed - non-stressed control sparrows; (2) fasted - sparrows fasted for intervals ranging from 20 min to 9 h; or (3) flown - sparrows flown in a wind tunnel for intervals between 20 min and 2.5 h while fasting. Half the sparrows from each group received DDT (DDT-dosed sparrows) and the other half corn oil vehicle only (vehicle sparrows). Trunk blood plasma was analyzed for thyroxine, triiodothyronine and corticosterone using radioimmunoassay. In the flown group, corticosterone was elevated (DDT-dosed 35.52 ng/ml, P < or = 0.05), and thyroxine was depressed (DDT-dosed 4.09 ng/ml, P < or = 0.05; vehicle 4.33 ng/ml, P < or = 0.05). Elevated corticosterone likely decreased thyroid hormone production through a negative feedback mechanism originating at the hypothalamus. Mean triiodothyronine concentrations did not differ among any of the test groups. Relative to time fasted and flown, thyroxine decreased in flown birds dosed with DDT (P < 0.001) and triiodothyronine decreased in fasted birds dosed with DDT (P = 0.004). The increased rate of hormone diminution may be a result of the ability of DDT to induce microsomal enzyme production.

Animals↗
PubMed2006

Control of annual reproductive cycle in the subtropical house sparrow (Passer domesticus): evidence for conservation of photoperiodic control mechanisms in birds.

BACKGROUND: In many birds, day length (= photoperiod) regulates reproductive cycle. The photoperiodic environment varies between different seasons and latitudes. As a consequence, species at different latitudes may have evolved separate photoperiodic strategies or modified them as per their adaptive need. We studied this using house sparrow as a model since it is found worldwide and is widely investigated. In particular, we examined whether photoperiodism in house sparrows (Passer domesticus) at 27 degrees N, 81 degrees E shared features with those exhibited by its conspecifics at high latitudes. RESULTS: Initial experiment described in the wild and captive conditions the gonad development and molt (only in captives) cycles over a 12-month period. Both male and female sparrows had similar seasonal cycles, linked with annual variations in day length; this suggested that seasonal reproduction in house sparrows was under the photoperiodic control. However, a slower testis and attenuated follicular growth among captives indicated that other (supplementary) factors are also involved in controlling the reproductive cycle. Next experiment examined if sparrows underwent seasonal variations in their response to stimulatory effects of long day lengths. When birds were transferred every month over a period of 1 year to 16 hours light:8 hours darkness (16L:8D) for 17-26 weeks, there was indeed a time-of-year effect on the growth-regression cycle of gonads. The final experiment investigated response of house sparrows to a variety of light-dark (LD) cycles. In the first set, sparrows were exposed for 31 weeks to photoperiods that were close to what they receive in between the period from sunrise to sunset at this latitude: 9L:15D (close to shortest day length in December), 12L:12D (equinox, in March and September) 15L:9D (close to longest day length in June). They underwent testicular growth and regression and molt in 12L and 15L photoperiods, but not in 9L photoperiod. In the second set, sparrows were exposed for 17 weeks to photoperiods with light periods extending to different duration of the daily photosensitivity rhythm (e.g. 2L:22D, 6L:18D, 10L:14D, 14L:10D, 18L:6D and 22L:2D). Interestingly, a slow and small testicular response occurred under 2L and 10L photoperiods; 6L:18D was non-inductive. On the other hand, 14L, 18L and 22L photoperiods produced testicular growth and subsequent regression response as is typical of a long day photostimulation. CONCLUSION: Subtropical house sparrows exhibit photoperiodic responses similar to that is reported for its population living at high latitudes. This may suggest the conservation of the photoperiodic control mechanisms in birds evolved over a long period of time, as a physiological strategy in a temporally changing environment ensuring reproduction at the best suited time of the year.

Journal Article↗
PubMed1984

A field study on the effects of Fort Morgan virus, an arbovirus transmitted by swallow bugs, on the reproductive success of cliff swallows and symbiotic house sparrows in Morgan County, Colorado, 1976.

We studied the transmission of Fort Morgan (FM) virus within colonies of nesting Cliff Swallows and House Sparrows under three bridges in Morgan County, Colorado during 1976. Nests were examined, and blood or brain specimens were collected from nestlings once or twice a week. Flying birds and small mammals were also studied. We analyzed nesting activity, virus isolations from nestlings of both species, fledging success, multiple infections within a brood of nestlings, infection frequency by age of nestlings, nestling mortality, and infection frequencies by avian species and bridge site. Fort Morgan virus was isolated from 7% (80/1, 156) of the blood and brain samples collected from nestlings. The duration of viremia for nestling House Sparrows was at least 3-4 days based on virus isolation from sequential blood samples. Viremia of nestling Cliff Swallows and House Sparrows did not reduce fledging success, nor were young nestling sparrows viremic more frequently than older nestling sparrows. Nest destruction (by falling down) was a more important cause of nestling mortality than FM virus infection. All age groups of nestling sparrows were viremic at equal rates, but younger nestlings (less than or equal to 7 days old) were more likely than older nestlings (greater than 7 days old) to develop an encephalitic infection. Among nestling House Sparrows, FM virus infections were clustered in time and space. Nestling House Sparrows with FM virus-infected nest-mates were infected more often than conspecifics whose nest-mates were not infected. We concluded that nestling Cliff Swallows and symbiotic House Sparrows that reside in swallow nesting colonies are the principal vertebrate hosts for the maintenance and amplification of FM virus.

Animals↗
PubMed2005

Monitoring urban heavy metal pollution using the House Sparrow (Passer domesticus).

The House Sparrow (Passer domesticus) is one of the most successful birds in the urban environment, and has a global distribution. The present study aims to provide baseline data about metals in sparrows from urban environments in the West Bank and to investigate the possibility of using the House Sparrow to monitor metal pollution in urban environments. Concentrations of Cu, Cd, Pb and Zn were measured in different tissues and organs of male and female juvenile (1-4 weeks old) and adult House Sparrows from the West Bank. Tissues and organs had the following order of metal richness: liver > stomach > bone > lung, feathers > muscles > egg contents, brain > heart > egg shell. Significant correlation coefficients were observed for the concentrations of Cu, Pb, and Zn in the egg shell and for the egg contents. Male and female Sparrows showed no significant differences in their metal concentrations. Adult Sparrows collected from rural areas were found to have significantly less Cu, Pb, and Zn (but not Cd) concentrations than those from urban environments. In order to investigate metal accumulation with age, metal concentrations were plotted against age stage (egg, 1-, 2-, 3-, and 4-week-old juveniles and adults). Significant relationships were observed between age stage and Cu, Pb, and Zn concentrations. The results provide some evidence for the potential of the House Sparrow as a biomonitor for urban heavy metal pollution. However, further issues regarding metal physiological regulation and the correlations between metals in the environment and those in tissues of the House Sparrows have to be addressed before recommending this bird as a biomonitor for urban metal pollution.

Animals↗
PubMed1983

The house sparrow (Passer domesticus) as a sentinel for St. Louis encephalitis virus.

Birds are the primary hosts for St. Louis encephalitis (SLE) virus in most of North America. Because the increased prevalence of antibody in House Sparrows (Passer domesticus) has been related to human cases, this species has been frequently used as a sentinel of SLE virus activity in urban areas. This study investigated the susceptibility of House Sparrows to two strains of SLE virus, measured antibody profiles, and evaluated the use of House Sparrows in an urban surveillance system. House Sparrows were susceptible to both strains of SLE virus inoculated, although not equally, and produced viremias sufficient to infect vector mosquitoes. Both hemagglutination-inhibiting (HI) and neutralizing (N) antibody developed rapidly and to high titers within 2 weeks after inoculation. Detectable humoral antibody began to disappear by 3 months, but persisted for 2 years in 27% for HI and 36% for N antibody of the surviving birds. However, all of the surviving birds were resistant to reinfection with SLE virus at 2 years after inoculation. The titer of HI antibody appeared to be useful in determining recent exposure to SLE virus. The experimental data on HI antibody development and persistence was related to field serologic data from House Sparrows. The monthly prevalences of SLE antibody for independent samples of sera from House Sparrows collected in Memphis, Tennessee, in 1980 were similar. SLE amplification in the House Sparrow population was delayed until September. The Memphis arbovirus surveillance system detected the amplification quickly, and responded with increased adult mosquito control in the focal areas. Urban surveillance of SLE utilizing House Sparrows as sentinels is discussed.

Animals↗
PubMed2006

Contrasting adaptive immune defenses and blood parasite prevalence in closely related Passer sparrows.

Immune system components differ in their functions and costs, and immune defense profiles are likely to vary among species with differing ecologies. We compared adaptive immune defenses in two closely related species that have contrasting inflammatory immune responses, the widespread and abundant house sparrow (Passer domesticus) and the less abundant tree sparrow (Passer montanus). We found that the house sparrow, which we have previously shown mounts weaker inflammatory responses, exhibits stronger adaptive immune defenses, including antibody responses, natural antibody titers, and specific T-cell memory, than the tree sparrow. Conversely, tree sparrows, which mount strong inflammatory responses, also mount stronger nonspecific inflammatory T-cell responses but weaker specific adaptive responses. Prevalence of avian malaria parasite infections, which are controlled by adaptive immune defenses, was higher in the geographically restricted tree sparrow than in the ubiquitous house sparrow. Together these data describe distinct immune defense profiles between two closely related species that differ greatly in numbers and distributions. We suggest that these immunological differences could affect fitness in ways that contribute to the contrasting abundances of the two species in North American and Western Europe.

Analysis of Variance↗
PubMed1985

Direct and circadian control of sparrow behavior by light and dark.

House sparrows, Passer domesticus, have perch-hopping activity (1) which was elicited by light (direct), and (2) which exhibited daily rhythms that were entrained by environmental light-dark cycles (circadian). When photoperiod was more than 14 hr, the sparrows' activity coincided with the light; when it was less than 14 hr, the birds were also active in the dark according to circadian predictions. Bimodality was dependent on photoperiod with the maximum incidence (75%) in LD16:8. Sparrows placed in LD1:11 (skeleton of 13:11) synchronized the onsets of their activity with the light beginning 8-18 hr after the time of the last L/D irrespective of when the birds experienced the first 1 hr light. Thirty-five percent of the sparrows advanced when they entrained to LD1:11 with the first pulse 8 hr after the last L/D; 76-87% of the sparrows delayed when they entrained to LD1:11 with the first pulse 2, 5 or 18 after the last L/D. Sparrows kept in exotic light-dark cycles (with periods of 10 min, 1.5 hr, 3.0 hr, 6.0 hr, 12 hr) were active in the light. Some birds displayed circadian rhythms superimposed on short period patterns. The period lengths of the circadian rhythms were shorter (22.8 hr) than in constant dark (24.2 hr). When sparrows subjected to LD1.5:1.5 or 36 hr of constant light were placed in constant dark, the phase of their activity onsets extrapolated to 15 hr after the last lights-off.

Animals↗
PubMed1998

Geographic analysis of nucleotide diversity and song sparrow (Aves: Emberizidae) population history.

Mitochondrial DNA (mtDNA) control-region (CR) sequences were analysed to address three questions regarding the evolution of geographical variation in song sparrows. (i) Are mtDNA sequences more informative about phylogenetic relationships and population history than previously published restriction fragment (RFLP) data? (ii) Are song sparrow CR sequences evolving in a selectively neutral manner? (iii) What do the haplotype cladogram and geographical pattern of nucleotide diversity (pi) suggest about the recent evolutionary history of song sparrow populations? Results from phylogenetic analyses of CR sequences corroborate RFLP results and reveal instances in which haplotypes do not group by locality. Neutrality tests (Tajima 1989a) suggest that song sparrow mtDNA is evolving in a selectively neutral manner, although exceptions are noted. A novel geographical pattern of pi suggests a model of song sparrow population history involving multiple Pleistocene refugia and colonization of some formerly glaciated regions from multiple sources. Moreover, application of coalescence theory to the haplotype cladogram suggests that two different haplotypes (48NF and 151HA) may have predominated in different parts of the song sparrow's range. This model provides insight into the current distribution of song sparrow mtDNA haplotypes and may explain the discordance between evolutionary history inferred from mtDNA and morphology in this species.

Animals↗
PubMed2006

Natural daylight restricted to twilights delays the timing of testicular regression but does not affect the timing of the daily activity rhythm of the house sparrow (Passer domesticus).

BACKGROUND: A stable and systematic daily change in light levels at dawn and dusk provides the most reliable indicator of the phase of the day. It is likely that organisms have evolved mechanisms to use these twilight transitions as the primary zeitgeber to adjust their circadian phases. In this study, we investigated under natural illumination conditions the effects of daylight exposure restricted to twilights on the timing of testicular regression and locomotor activity of the house sparrow (Passer domesticus), which possesses a strongly self-sustaining circadian system. METHODS AND RESULTS: Two experiments were performed on adult male house sparrows. Beginning in the third week of April, the first experiment examined whether exposure to natural daylight only during twilights influenced the timing of testicular regression and concomitant changes in testosterone-dependent beak color of reproductively mature sparrows. Interestingly, there was a significant delay in testicular regression and depigmentation of the beak in sparrows exposed to natural daylight (NDL) only during twilights as compared to those exposed to NDL all day. The second experiment examined twice in the year, around the equinoxes (March and September), the effects of exposure to twilights only on the daily activity rhythm of sparrows kept in an outdoor aviary. Five of 7 birds continued exhibiting entrained activity rhythms when exposed only to twilights (NDL minus day light from sunrise to sunset) in September, but not in March. Both in NDL and twilight conditions, March birds had significantly lower activity counts than September birds. CONCLUSION: Exposure to natural daylight only during twilights delayed the timing of testicular regression and concomitant depigmentation of the beak but did not affect the daily activity rhythm in male sparrows. This suggests that daily twilights can serve as cues for regulation of the circadian activity rhythm but not for the photoperiodic regulation of testicular cycle in the house sparrow.

Journal Article↗