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Marilyn Ramenofsky - One of the best experts on this subject based on the ideXlab platform.
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2004b Plasma corticosterone increases during migratory restlessness in the captive White-Crowned Sparrow Zonotrichia leucophrys gambelii
2020Co-Authors: Mėta M Landys, John C Wingfield, Marilyn RamenofskyAbstract:Abstract Plasma corticosterone increases during the period of spring migration in a variety of bird species. Long-distance migrants show elevations in corticosterone specifically in association with the stage of flight, suggesting that corticosterone may support flight-related processes, for example, locomotor activity and/or energy mobilization. The pattern of corticosterone secretion as it relates to migratory flight has hitherto not been clearly described in migrants that frequently interrupt flight to refuel, for example, the Gambel's White-Crowned Sparrow (Zonotrichia leucophrys gambelii). The Gambel's White-Crowned Sparrow fuels by day and expresses peak migratory activity during the first few hours of night. To determine if plasma corticosterone increases in association with the stage of migratory flight also in this short-bout migrant, we induced captive White-Crowned Sparrows to enter into the migratory condition by placing photosensitive birds on long days (16L:8D) and then evaluated birds for plasma corticosterone and locomotor activity during four time points of the day. Patterns found in longday birds were compared to those observed in short-day controls (8L:16D). Differences in energy metabolism as determined from plasma metabolites were also evaluated. We found that locomotor activity and corticosterone were significantly elevated at the onset of the dark period, but only in long-day birds. Plasma h-hydroxybutyrate (a ketone body) was also elevated. Thus, findings suggest that plasma corticosterone and ketogenesis increase in association with migratory restlessness in a short-bout migrant. In fact, corticosterone may play a regulatory role, because it shows a trend to increase already before night-time activity.
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migration pattern of gambel s white crowned Sparrow along the pacific flyway
Journal of Ornithology, 2019Co-Authors: Jesse S Krause, Nathaniel E. Seavy, Zoltán Németh, Simeon Lisovski, Keith A Hobson, Marilyn RamenofskyAbstract:White-Crowned Sparrow (Zonotrichia leucophrys) populations of western North America exhibit dramatic differences in life history strategies including migration behavior. However, individual migration strategies and population-level migratory patterns remain largely unknown for this species. Here, we focused on the long-distance migratory subspecies, Gambel’s White-Crowned Sparrow (Zonotrichia leucophrys gambelii). We used ringing, tracking and stable hydrogen isotope (δ2H) analysis of individuals migrating along the Pacific Flyway to assess individual phenology and routes as well as the pattern of connectivity between breeding and non-breeding sites. Results from all three methods, consisting of 79 ring recoveries, four light level geolocator tracks and 388 feather δ2H values, indicate low degrees of migratory connectivity. The isotope data provide evidence for leapfrog migration with the more southerly populations traveling greater distances to the breeding grounds than more centrally wintering individuals. Location estimates of four annual journeys revealed individually consistent migration strategies with relatively short flight bouts separated by two to three and two to six stopover sites during spring and autumn migration, respectively. However, combined results from all methods indicate high variability in migration distance among individuals. These findings confirm the phenotypic flexibility observed within this species and highlight the potential of White-Crowned Sparrows for further investigations of evolutionary adaptations to ongoing changes in the environment.
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altered expression of pectoral myosin heavy chain isoforms corresponds to migration status in the white crowned Sparrow zonotrichia leucophrys gambelii
Royal Society Open Science, 2016Co-Authors: Brandy P. Velten, Kenneth C. Welch, Marilyn RamenofskyAbstract:Birds undergo numerous changes as they progress through life-history stages, yet relatively few studies have examined how birds adapt to both the dynamic energetic and mechanical demands associated...
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annual hematocrit profiles in two subspecies of white crowned Sparrow a migrant and a resident comparison
Physiological and Biochemical Zoology, 2016Co-Authors: Jesse S Krause, Zoltán Németh, Marilyn Ramenofsky, Jonathan H Perez, Helen E Chmura, John C WingfieldAbstract:Hematocrit is an easily measured parameter that can be used to assess changes in oxygen carrying capacity necessitated by fluctuations in metabolic demands. Most hematocrit studies draw conclusions from changes in hematocrit that occur over a small sampling interval without an understanding of the variation that exists across the annual cycle. White-Crowned Sparrows provide an excellent model system due to the existence of a resident subspecies (Zonotrichia leucophrys nuttalli) that serves as a natural control for a migrant subspecies (Zonotrichia leucophrys gambelii). Comparing these two subspecies allows for the investigation of adaptive physiological changes at each life-history stage (i.e., migration, breeding, molt, etc.) in response to changing metabolic demands. Of particular interest, this subspecies comparison, by both calendar month and life-history stage, allows for the separation of adaptive increases in hematocrit due to migration from the natural seasonal variation in hematocrit. Hematocrit levels for males and females ranged throughout the year between 42%-47% and 40%-47% in the resident and between 45%-58% and 45%-56% in the migrant. In both subspecies, hematocrit levels were elevated during the breeding season compared to the nonbreeding season, and levels were reduced in females during egg laying. When grouped by life-history stage, hematocrit levels were always higher in the migrant compared to the resident. During the months in which migration occurred, hematocrit levels were 10%-12% higher in the migrant compared to the resident subspecies. These data suggest differential regulation of hematocrit between the two subspecies that may be attributed to phenotypic plasticity or genetic differences.
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Supplementary Figure 1: Comparison of RGB and greyscale images of SDH-stained sections from Altered expression of pectoral myosin heavy chain isoforms corresponds to migration status in the White-Crowned Sparrow (Zonotrichia leucophrys gambelii)
2016Co-Authors: Brandy P. Velten, Kenneth C. Welch, Marilyn RamenofskyAbstract:Birds undergo numerous changes as they progress through life-history stages, yet relatively few studies have examined how birds adapt to both the dynamic energetic and mechanical demands associated with such transitions. Myosin heavy chain (MyHC) expression, often linked with muscle fibre type, is strongly correlated with a muscle's mechanical power generating capability, thus we examined several morphological properties, including MyHC expression of the pectoralis, in a long-distance migrant, the White-Crowned Sparrow (Zonotrichia leucophrys gambelii) throughout the progression from winter, spring departure and arrival on breeding grounds. White-Crowned Sparrows demonstrated significant phenotypic flexibility throughout the seasonal transition, including changes in prealternate moult status, lipid fuelling, body condition and flight muscle morphology. Pectoral MyHC expression also varied significantly over the course of the study. Wintering birds expressed a single, newly classified adult fast 2 isoform. At spring departure, pectoral isoform expression included two MyHC isoforms: the adult fast 2 isoform along with a smaller proportion of a newly present adult fast 1 isoform. By spring arrival, both adult fast isoforms present at departure remained, yet expression had shifted to a greater relative proportion of the adult fast 1 isoform. Altering pectoral MyHC isoform expression in preparation for and during spring migration may represent an adaptation to modulate muscle mechanical output to support long-distance flight
Douglas A. Nelson - One of the best experts on this subject based on the ideXlab platform.
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geographical variation in song phrases differs with their function in white crowned Sparrow song
Animal Behaviour, 2017Co-Authors: Douglas A. NelsonAbstract:Complex signals that convey diverse forms of information may face conflicting pressures on their structure. Certain messages, such as species identification or ‘alerting’ receivers may require a relatively invariant signal structure, while messages about dialect or individual identity and motivation require structural diversity within and among individuals of a species. A resolution to this conflict is to encode different messages in different parts of the signal. When the signal is learned, as in birdsong, parts of the signal may develop along differing developmental pathways in order to produce the necessary signal variation. I tested the hypothesis that three phrases in the song of the Puget Sound White-Crowned Sparrow, Zonotrichia leucophrys pugetensis, that are inferred to convey different messages will vary in their patterns of geographical variation along a 560 km long transect of the Pacific northwest coast of North America. I measured acoustic features of the songs of 267 males and tested for geographical structure using Mantel tests and Mantel correlograms. As predicted, the introductory whistle phrase, inferred to have an ‘alerting’ function, was geographically invariant. In contrast, the note complex and trill phrases, which convey information about individual identity and geographical origin, both decreased in similarity between males as distance increased. The two phrases have somewhat independent patterns of geographical variation. I suggest that differences in how these phrases develop, as measured in laboratory song-learning experiments, coupled with dispersal may contribute to the differing distributions.
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alerting and message components of white crowned Sparrow song differ in structure and environmental transmission
Behaviour, 2016Co-Authors: Douglas A. Nelson, Erica Szeyller, Angelika PoeselAbstract:Signals that function over long distances, such as bird songs, must be detectable and discriminable from other signals by receivers despite being attenuated and degraded during environmental transmission. The acoustic design features that enhance detectability may conflict with those that enhance discriminability of different messages (e.g., the sender’s motivation or identity). The songs of many bird species begin with simple tonal notes, hypothesized to alert receivers to the following song parts. We describe structural differences in the songs of the Puget Sound White-Crowned Sparrow (Zonotrichia leucophrys pugetensis) and performed a transmission experiment to test if the whistle transmits differently than other song parts. As expected for an alerting component, the whistle phrases across different song types were highly similar, suffered less degradation when transmitted, and were produced at higher amplitude than the other two phrase types. These results suggest that in White-Crowned Sparrows alerting and message-bearing song phrases transmit differently.
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Tutor choice and imitation accuracy during song learning in a wild population of the Puget Sound White-Crowned Sparrow
Behavioral Ecology and Sociobiology, 2014Co-Authors: Douglas A. Nelson, Angelika PoeselAbstract:Songbirds learn to sing by modeling their songs on the songs of other males through a process of social learning. Models of social learning predict that animals should be selective in what and when they learn. In this study, we asked whether young males in a wild population of the Puget Sound White-Crowned Sparrow, Zonotrichia leucophrys pugetensis , were selective in their choice of tutor models and what factors influenced how accurately they imitated tutors’ songs. We first examined two strategies for tutor choice: whether pupils have a conformity bias and/or a preference for high-quality tutors. In keeping with a conformity bias, tutors that sang song types that were relatively common within a radius of about 500 m of their territory were more likely to be imitated than were tutors that sang rarer song types. Most potential tutors were not imitated by pupils. Aspects of tutor quality, such as age, pairing status, and survival to the next year had no effect on whether a tutor’s song was imitated. Secondly, we tested whether pupil repertoire size, pupil quality, and local abundance of tutor models affected the accuracy of song imitations. We found a trade-off between repertoire size and tutor imitation accuracy with males that sang two or more song types developing significantly poorer imitations than males that sang one type. We discuss possible functions of a conformity learning strategy and factors that could produce a trade-off between imitation accuracy and repertoire size.
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Song sharing correlates with lifetime social pairing success but not territory tenure in the Puget Sound White-Crowned Sparrow
Behavioral Ecology and Sociobiology, 2013Co-Authors: Douglas A. Nelson, Angelika PoeselAbstract:Imitative song learning in birds often results in the formation of vocal dialects or local song neighborhoods in which males in close proximity share very similar songs. If song sharing confers a selective advantage due to intra-sexual competition or inter-sexual mate choice, song sharing should enhance the singer’s territory tenure or lifetime pairing success. We tested this in a migratory population of the Puget Sound White-Crowned Sparrow, Zonotrichia leucophrys pugetensis , in which some territory neighbors share whole songs. Song sharing with territory neighbors in the first year on territory did not correlate with territory tenure but correlated positively with social pairing success throughout a male’s lifetime when length of territory tenure was controlled. Thus, song sharing in this migratory population does not appear to confer a benefit in male–male interactions, at least as measured by the length of territory tenure. However, males that share songs do benefit from higher lifetime pairing success. Combined with the data available for other species, it appears that intra- and inter-sexual selection may have stronger effects on song sharing in sedentary and migratory populations, respectively.
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song sharing correlates with social but not extrapair mating success in the white crowned Sparrow
Behavioral Ecology, 2012Co-Authors: Angelika Poesel, Douglas A. Nelson, Lisle H GibbsAbstract:Bird song is a prominent example of a trait under inter- and intrasexual selection. Performance-related aspects of bird song have been shown to vary among males and to influence territorial interactions as well as female mate choice. In oscine songbirds, song is different from many other sexually selected traits in that it is learned. As a result of learning, territorial neighbors share songs in some species. Thus, social interactions may be influenced not only by how well a male performs song but also by whom he shares song with. Here, we test the hypothesis that song sharing indicates local song learning and experience from which females may benefit. We examine the prediction that song sharing correlates with reproductive success. During our 4-year field study on White-Crowned Sparrows Zonotrichia leucophrys pugetensis, we found that yearling males that shared song with at least one territorial neighbor had higher social mating success than nonsharers. At the same time, song performance did not significantly correlate with social mating success but did correlate with paternity loss. Males with high performance were more likely to lose paternity than males with low performance. No song feature correlated with gaining paternity. We conclude that song sharing may be an indicator of male quality and stable social neighborhoods which may be a direct benefit to females. Furthermore, our results may provide a functional explanation for a developmental process where songbirds adjust their song to the local social neighborhood.
John C Wingfield - One of the best experts on this subject based on the ideXlab platform.
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2004b Plasma corticosterone increases during migratory restlessness in the captive White-Crowned Sparrow Zonotrichia leucophrys gambelii
2020Co-Authors: Mėta M Landys, John C Wingfield, Marilyn RamenofskyAbstract:Abstract Plasma corticosterone increases during the period of spring migration in a variety of bird species. Long-distance migrants show elevations in corticosterone specifically in association with the stage of flight, suggesting that corticosterone may support flight-related processes, for example, locomotor activity and/or energy mobilization. The pattern of corticosterone secretion as it relates to migratory flight has hitherto not been clearly described in migrants that frequently interrupt flight to refuel, for example, the Gambel's White-Crowned Sparrow (Zonotrichia leucophrys gambelii). The Gambel's White-Crowned Sparrow fuels by day and expresses peak migratory activity during the first few hours of night. To determine if plasma corticosterone increases in association with the stage of migratory flight also in this short-bout migrant, we induced captive White-Crowned Sparrows to enter into the migratory condition by placing photosensitive birds on long days (16L:8D) and then evaluated birds for plasma corticosterone and locomotor activity during four time points of the day. Patterns found in longday birds were compared to those observed in short-day controls (8L:16D). Differences in energy metabolism as determined from plasma metabolites were also evaluated. We found that locomotor activity and corticosterone were significantly elevated at the onset of the dark period, but only in long-day birds. Plasma h-hydroxybutyrate (a ketone body) was also elevated. Thus, findings suggest that plasma corticosterone and ketogenesis increase in association with migratory restlessness in a short-bout migrant. In fact, corticosterone may play a regulatory role, because it shows a trend to increase already before night-time activity.
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daily circadian and seasonal changes of rhodopsin like encephalic photoreceptor and its involvement in mediating photoperiodic responses of gambel s white crowned Sparrow zonotrichia leucophrys gambelii
Brain Research, 2018Co-Authors: Hongfeng Zhao, Gang Wang, Junxia Jiang, John C WingfieldAbstract:Extra-retinal, non-pineal, encephalic photoreceptors (EP) play important roles in mediating development of the reproductive system by the annual change in day length (photoperiodic gonadal response - PGR) in birds. However, the distribution of rhodopsin-like EPs and their functional daily, circadian and seasonal changes are still unclear in the avian brain. This study identifies two novel groups of rhodopsin-immunoreactive cells in the nucleus paraventricularis magnocellularis (PVN) of the hypothalamus and in the medial basal hypothalamus (MBH) in a seasonally breeding species, Gambel's White-Crowned Sparrow (Zonotrichia leucophrys gambelii). In the PVN, rhodopsin-ir cell number showed both daily and circadian changes with more labeled cells apparent in the night phase in photosensitive birds, while only circadian changes were observed involving fewer labeled cells in the night phase in photorefractory birds. Single long day photo-stimulation significantly decreased the rhodopsin-ir cell number only in photosensitive birds, coincident with a rise in plasma levels of luteinizing hormone (LH). In the MBH, rhodopsin-ir cell number did not show daily, circadian or single long day induced changes in either photoperiodic states. But, overall these rhodopsin expressing neurons significantly increased from photosensitive to photorefractory states. In the median eminence (ME), more intense rhodopsin-ir was detected in photorefractory birds compared to photosensitive birds. For expression of GnRH and vasoactive intestinal polypeptide (VIP), seasonal differences were found with opposite relationships, consistent with previous studies. Our results suggest different roles of the two groups of rhodopsin-like EPs in the regulation of PGR in White-Crowned Sparrows.
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The Annual Cycle of Plasma irLH and Steroid Hormones in Feral Populations of the White-Crowned Sparrow,
2016Co-Authors: Zonotrichia Leucophrys Gambelii, John C Wingfield, Donald S. FarnerAbstract:Plasma levels of immunoreactive luteinizing hormone (irLH) and 5 steroid hormones have been measured through the course of the winter breeding season and vernal and autumnal migration in both sexes of the White-Crowned Sparrow, Zonotrichia leucophrys gambelii. Birds were captured in mist nets or traps on wintering grounds in Washington and California and on the breeding area in the vicinity of Fairbanks, Alaska. Blood samples were collected from a wing vein as soon after capture as possible. Birds were then individually marked with a unique combination of 1 or 2 colored leg bands for identification in field observations and laparotomy performed to assess the reproductive state. After sampling, all birds were released for subsequent observation and recapture. During autumn and winter, the levels of irLH and sex hormones in the plasma are low in both sexes. In spring (April and May), they begin to increase becoming maximal coincidentally with maximal gonadal weights, establishment of territory, mating and courtship. During incubation and feeding of young, plasma irLH and sex steroid levels decline to basal levels, but there is only a gradual decrease in weight of the testes. By the time parent birds are feeding fledglings, there is a rapid involution of the gonads followed closely by the onset of postnuptial molt. Plasma levels of corticosterone are high in both sexes in January, but much lower in the early spring. In males during vernal migration, there is a dramatic increase to a high level that persists throughout the breeding season. In females, plasma hormone levels remain low during vernal migration, but then increase during the time of ovulation and oviposition. Basal levels in plasma corticosterone occur in both sexes during postnuptial molt. In contrast to vernal migration, a slight increase in plasma corticosterone occurs during autumnal migration in females, but not in males
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annual hematocrit profiles in two subspecies of white crowned Sparrow a migrant and a resident comparison
Physiological and Biochemical Zoology, 2016Co-Authors: Jesse S Krause, Zoltán Németh, Marilyn Ramenofsky, Jonathan H Perez, Helen E Chmura, John C WingfieldAbstract:Hematocrit is an easily measured parameter that can be used to assess changes in oxygen carrying capacity necessitated by fluctuations in metabolic demands. Most hematocrit studies draw conclusions from changes in hematocrit that occur over a small sampling interval without an understanding of the variation that exists across the annual cycle. White-Crowned Sparrows provide an excellent model system due to the existence of a resident subspecies (Zonotrichia leucophrys nuttalli) that serves as a natural control for a migrant subspecies (Zonotrichia leucophrys gambelii). Comparing these two subspecies allows for the investigation of adaptive physiological changes at each life-history stage (i.e., migration, breeding, molt, etc.) in response to changing metabolic demands. Of particular interest, this subspecies comparison, by both calendar month and life-history stage, allows for the separation of adaptive increases in hematocrit due to migration from the natural seasonal variation in hematocrit. Hematocrit levels for males and females ranged throughout the year between 42%-47% and 40%-47% in the resident and between 45%-58% and 45%-56% in the migrant. In both subspecies, hematocrit levels were elevated during the breeding season compared to the nonbreeding season, and levels were reduced in females during egg laying. When grouped by life-history stage, hematocrit levels were always higher in the migrant compared to the resident. During the months in which migration occurred, hematocrit levels were 10%-12% higher in the migrant compared to the resident subspecies. These data suggest differential regulation of hematocrit between the two subspecies that may be attributed to phenotypic plasticity or genetic differences.
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decreases in mineralocorticoid but not glucocorticoid receptor mrna expression during the short arctic breeding season in free living gambel s white crowned Sparrow zonotrichia leucophrys gambelii
Journal of Neuroendocrinology, 2015Co-Authors: Jesse S Krause, John C Wingfield, M A Mcguigan, Valerie Bishop, Simone MeddleAbstract:The acute stress response in vertebrates is a highly adaptive suite of physiological and behavioural mechanisms that promote survival in the face of deleterious stimuli from the environment. Facultative changes of physiology and behaviour are mediated through changes in circulating levels of glucocorticoids (corticosterone, cortisol) and their subsequent binding to the high-affinity mineralocorticoid receptor (MR) or the low-affinity glucocorticoid receptor (GR). Free-living male wild Gambel's White-Crowned Sparrows (Zonotrichia leucophrys gambelii) display annual fluctuations in the stress response with marked attenuation during the transition from the pre-parental to the parental stage. We investigated whether this rapid reduction in the stress response is mediated through changes in MR and GR mRNA expression in the brain using in situ hybridisation. MR mRNA expression was found to be significantly lower in the hippocampus as the male birds became parental. No changes were observed in GR mRNA expression in the paraventricular nucleus (PVN) or preoptic area (POA) at this time. No significant correlations were found between initial capture levels of corticosterone and GR or MR mRNA expression. No differences were found in basal levels of corticosterone between pre-parental and parental in birds collected for in situ hybridisation. Stress response data revealed no difference at baseline but reductions in peak levels of corticosterone as birds became parental. These data suggest that changes in MR expression may be important for the regulation of the stress response or behavioural stress sensitivity with respect to promoting parental care and investment.
Angelika Poesel - One of the best experts on this subject based on the ideXlab platform.
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alerting and message components of white crowned Sparrow song differ in structure and environmental transmission
Behaviour, 2016Co-Authors: Douglas A. Nelson, Erica Szeyller, Angelika PoeselAbstract:Signals that function over long distances, such as bird songs, must be detectable and discriminable from other signals by receivers despite being attenuated and degraded during environmental transmission. The acoustic design features that enhance detectability may conflict with those that enhance discriminability of different messages (e.g., the sender’s motivation or identity). The songs of many bird species begin with simple tonal notes, hypothesized to alert receivers to the following song parts. We describe structural differences in the songs of the Puget Sound White-Crowned Sparrow (Zonotrichia leucophrys pugetensis) and performed a transmission experiment to test if the whistle transmits differently than other song parts. As expected for an alerting component, the whistle phrases across different song types were highly similar, suffered less degradation when transmitted, and were produced at higher amplitude than the other two phrase types. These results suggest that in White-Crowned Sparrows alerting and message-bearing song phrases transmit differently.
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Tutor choice and imitation accuracy during song learning in a wild population of the Puget Sound White-Crowned Sparrow
Behavioral Ecology and Sociobiology, 2014Co-Authors: Douglas A. Nelson, Angelika PoeselAbstract:Songbirds learn to sing by modeling their songs on the songs of other males through a process of social learning. Models of social learning predict that animals should be selective in what and when they learn. In this study, we asked whether young males in a wild population of the Puget Sound White-Crowned Sparrow, Zonotrichia leucophrys pugetensis , were selective in their choice of tutor models and what factors influenced how accurately they imitated tutors’ songs. We first examined two strategies for tutor choice: whether pupils have a conformity bias and/or a preference for high-quality tutors. In keeping with a conformity bias, tutors that sang song types that were relatively common within a radius of about 500 m of their territory were more likely to be imitated than were tutors that sang rarer song types. Most potential tutors were not imitated by pupils. Aspects of tutor quality, such as age, pairing status, and survival to the next year had no effect on whether a tutor’s song was imitated. Secondly, we tested whether pupil repertoire size, pupil quality, and local abundance of tutor models affected the accuracy of song imitations. We found a trade-off between repertoire size and tutor imitation accuracy with males that sang two or more song types developing significantly poorer imitations than males that sang one type. We discuss possible functions of a conformity learning strategy and factors that could produce a trade-off between imitation accuracy and repertoire size.
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Song sharing correlates with lifetime social pairing success but not territory tenure in the Puget Sound White-Crowned Sparrow
Behavioral Ecology and Sociobiology, 2013Co-Authors: Douglas A. Nelson, Angelika PoeselAbstract:Imitative song learning in birds often results in the formation of vocal dialects or local song neighborhoods in which males in close proximity share very similar songs. If song sharing confers a selective advantage due to intra-sexual competition or inter-sexual mate choice, song sharing should enhance the singer’s territory tenure or lifetime pairing success. We tested this in a migratory population of the Puget Sound White-Crowned Sparrow, Zonotrichia leucophrys pugetensis , in which some territory neighbors share whole songs. Song sharing with territory neighbors in the first year on territory did not correlate with territory tenure but correlated positively with social pairing success throughout a male’s lifetime when length of territory tenure was controlled. Thus, song sharing in this migratory population does not appear to confer a benefit in male–male interactions, at least as measured by the length of territory tenure. However, males that share songs do benefit from higher lifetime pairing success. Combined with the data available for other species, it appears that intra- and inter-sexual selection may have stronger effects on song sharing in sedentary and migratory populations, respectively.
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song sharing correlates with social but not extrapair mating success in the white crowned Sparrow
Behavioral Ecology, 2012Co-Authors: Angelika Poesel, Douglas A. Nelson, Lisle H GibbsAbstract:Bird song is a prominent example of a trait under inter- and intrasexual selection. Performance-related aspects of bird song have been shown to vary among males and to influence territorial interactions as well as female mate choice. In oscine songbirds, song is different from many other sexually selected traits in that it is learned. As a result of learning, territorial neighbors share songs in some species. Thus, social interactions may be influenced not only by how well a male performs song but also by whom he shares song with. Here, we test the hypothesis that song sharing indicates local song learning and experience from which females may benefit. We examine the prediction that song sharing correlates with reproductive success. During our 4-year field study on White-Crowned Sparrows Zonotrichia leucophrys pugetensis, we found that yearling males that shared song with at least one territorial neighbor had higher social mating success than nonsharers. At the same time, song performance did not significantly correlate with social mating success but did correlate with paternity loss. Males with high performance were more likely to lose paternity than males with low performance. No song feature correlated with gaining paternity. We conclude that song sharing may be an indicator of male quality and stable social neighborhoods which may be a direct benefit to females. Furthermore, our results may provide a functional explanation for a developmental process where songbirds adjust their song to the local social neighborhood.
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Song length variation serves multiple functions in the White-Crowned Sparrow
Behavioral Ecology and Sociobiology, 2011Co-Authors: Douglas A. Nelson, Angelika PoeselAbstract:A wide variety of hypotheses has been proposed to explain the structural diversity in bird song repertoires. Song diversity is frequently described in terms of song “types” or within-type “variants.” Male Puget Sound White-Crowned Sparrows, Zonotrichia leucophrys pugetensis , produce variants of their single adult song type by altering the number of repetitions of syllables in the terminal trill. We tested whether variation in trill length correlated with distance to the receiver and with signaling context as predicted by the eavesdropping avoidance hypothesis and the strategic signaling hypothesis. In accordance with the eavesdropping avoidance hypothesis, males sang variants with shorter trills, and sang quieter and less frequently when near their mate during the incubation phase than during spontaneous singing while unpaired. Males also sang variants with short trills, but at a high rate and variable amplitude when within 10 m of an opponent during close male–male territorial interactions. In agreement with the strategic signaling hypothesis, males decreased trill length immediately before chasing an opponent, but did not change length consistently prior to flight. We conclude that the occurrence of short quiet songs sung near the mate agrees with predictions of the eavesdropping avoidance hypothesis, while short songs sung near other males are best explained by the strategic signaling hypothesis. Trill length variation may be a conventional signal of aggressive intentions in male–male contests stabilized by receiver-imposed retaliation costs.
Jill A Soha - One of the best experts on this subject based on the ideXlab platform.
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cultural evolution of puget sound white crowned Sparrow song dialects
Ethology, 2004Co-Authors: Douglas A. Nelson, Karen I Hallberg, Jill A SohaAbstract:The songs of male Puget Sound White-Crowned Sparrows currently form about 12 dialects along the Pacific Northwest coast. In his survey of 1970, Baptista (Condor 1977; 79: 356–370) defined six of the dialects based on the song’s terminal trill because most males at each locality shared the simple syllables (SSs) in this trill. The complex syllables (CSs) in the song’s introduction varied among males at a locality, and were often shared among localities. From 1997 to 2004 we revisited nine of the sites Baptista studied to determine whether the SSs and CSs had changed over the 30-yr interval. Using Baptista’s catalogs of SS and CS types as bases for comparison, we found that the relative proportions of CS types changed significantly more over time than did the proportions of SS types. These results suggest that SSs and CSs evolve independently. Observations were also made on the developmental mechanisms that either produce diversity or maintain uniformity in song phrases. In a survey of 670 field-recorded songs, unique improvizations occurred significantly more often in CSs than in SSs. In a laboratory experiment using hand-reared males and multiple song tutors, males were significantly more accurate in imitating SSs than CSs. In choosing their final song to keep from their overproduced repertoire, yearling males tended to retain the song type that matched the SSs in the song played back to them. We conclude by discussing how differences in the functions served by these two song phrases may have led to their different rates of cultural evolution.
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perception of geographical variation in song by male puget sound white crowned Sparrows zonotrichia leucophrys pugetensis
Animal Behaviour, 2004Co-Authors: Douglas A. Nelson, Jill A SohaAbstract:Abstract The songs of male Puget Sound White-Crowned Sparrows form about 13 dialects along the Pacific Northwest coast of North America. In his original description of dialects in this subspecies, Baptista (1977, Condor , 79, 356–370) defined dialects by the terminal trill portion of the song because most males at a given location sing the same trill. Complex syllables in the introductory part of the song vary between males at a sample location and occur over a wider geographical range than trills. Baptista also recognized two superdialects or ‘themes’ based on differences in the phrase order within songs. We performed three playback experiments to territorial male White-Crowned Sparrows using both natural and computer-modified stimuli to test which acoustic features of song these birds attend to. Two of the experiments were conducted in nine dialect areas spanning nearly the entire geographical range of the subspecies. The results of the first such experiment indicate that across dialect areas, males give stronger responses (increased song rate and a shorter approach distance) to natural songs from the local dialect than they do to songs from a neighbouring dialect, a different theme, or another subspecies of White-Crowned Sparrow. Two experiments using modified stimuli conducted either across nine dialects or in one dialect led to the same conclusion: substitution of the trill from a neighbouring dialect into a song elicited weaker responses relative to the local control than did substitution of a neighbouring dialect's introduction. We conclude that the response of male Puget Sound White-Crowned Sparrows to playback is influenced most by variation in the song's trill. We found no evidence that the birds recognize ‘superdialects’ as do humans.
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cues for early discrimination of conspecific song in the white crowned Sparrow zonotrichia leucophrys
Ethology, 2001Co-Authors: Jill A Soha, Peter MarlerAbstract:In song learning, White-Crowned Sparrows (Zonotrichia leucophrys) begin memorizing conspecific song models at around 20 d of age. Even prior to song memorization, however, between 10 and 20 d of age, these birds respond differently to playbacks of conspecific and heterospecific songs. To investigate the acoustic cues underlying this early song discrimination, we measured the vocal responses of newly fledged young to playbacks of modified conspecific and heterospecific songs. Fledgling White-Crowned Sparrows responded more strongly to songs containing conspecific notes than to songs containing notes from other species. In contrast, the presence or placement of an introductory whistle, present in all White-Crowned Sparrow songs, did not affect response levels. A whistle has previously been shown to serve as an acoustic cue for song memorization and production in this species. Such different responses to the species-typical introductory whistle at different stages suggests that developmental changes occur in the template system underlying song learning, the factors governing song recognition, or both.
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a species specific acoustic cue for selective song learning in the white crowned Sparrow
Animal Behaviour, 2000Co-Authors: Jill A Soha, Peter MarlerAbstract:Song learning in birds is paradoxical. Without tutoring, songbirds do not develop normal songs. Yet despite this inability, birds possess extensive foreknowledge, in a mechanistic sense, about the normal song of their species. When given a choice of tape recordings, young, naive songbirds select sounds of their own species for imitation. We tape-tutored White-Crowned Sparrows, Zonotrichia leucophrys oriantha, with a set of manipulated songs to investigate whether the introductory whistle universally present in White-Crowned Sparrow song guides selective song learning in this species. Our results confirm that this whistle serves as a cue for song learning, enabling acquisition of normally rejected sounds of other species, including hermit thrush, Catharus guttatus, notes, which have a sound quality distinct from that of natural White-Crowned Sparrow phrases. Our results support the conclusion that sensory mechanisms rather than motor constraints are primarily responsible for the selectivity seen in song learning.
