The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform
Michael T. Murphy - One of the best experts on this subject based on the ideXlab platform.
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multistate mark recapture analysis reveals no effect of blood sampling on survival and recapture of eastern kingbirds Tyrannus Tyrannus
The Auk, 2011Co-Authors: Lucas James Redmond, Michael T. MurphyAbstract:ABSTRACT. The experimentally supported and prevailing opinion is that blood sampling has few to no long-term effects on survival of birds when conducted properly, and blood sampling has become a vital addition to the toolbox of many ornithologists. However, many of the studies that concluded that blood sampling had negligible effects on birds used approaches that did not account for temporary emigration and probability of capture. To date, the only study to have done so found that blood sampling had a strong negative effect on survival. We conducted a mark-recapture analysis of 8 years of banding and bleeding data on Eastern Kingbirds (Tyrannus Tyrannus) to determine whether survival was negatively influenced by blood sampling. Our analyses adjusted for temporary emigration and probability of recapture and accounted for (1) transitions between the bled and the nonbled state and (2) a change in protocol roughly midway through the study that resulted in a change from single to often multiple (and larger) dr...
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reproductive correlates of spring arrival date in the eastern kingbird Tyrannus Tyrannus
Journal of Ornithology, 2011Co-Authors: Michael T. Murphy, Lucas James Redmond, Nathan W Cooper, Amy C DolanAbstract:Harsh weather in spring presents energetic challenges to birds during migration and upon reaching the breeding grounds, and yet, birds often arrive well before breeding begins. We studied a population of Eastern Kingbirds in eastern Oregon from 2004 through 2007. Early arriving kingbirds faced the poorest weather conditions, and therefore we predicted that benefits of early arrival must exist to balance the presumed costs. Early-arriving kingbirds were more likely to both acquire a high-quality territory and to replace nests after failure. Early-arriving birds also bred early, and early breeding led to larger clutches and greater production of young. Early-arriving males also sired more extra-pair young than later arrivers. Our data suggest that arrival date is in part influenced by individual quality, and that arrival date has reproductive consequences, with the primary benefits of early arrival being the acquisition of a high-quality territory, early breeding, and increased probability of replacing failed initial nests.
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maternal characteristics and the production and recruitment of sons in the eastern kingbird Tyrannus Tyrannus
Behavioral Ecology and Sociobiology, 2009Co-Authors: Amy C Dolan, Michael T. Murphy, Lucas James Redmond, Debbie DuffieldAbstract:Sex allocation theory predicts that if variance in reproductive success differs between the sexes, females who are able to produce high-quality young should bias offspring sex ratio towards the sex with the higher potential reproductive success. We tested the hypothesis that high-quality (i.e., heavy) female eastern kingbirds (Tyrannus Tyrannus) that bred early in the breeding season would produce male-biased clutches. A significant opportunity for sexual selection also exists in this socially monogamous but cryptically polygamous species, and we predicted that successful extra-pair (EP) sires would be associated with an excess of male offspring. Although population brood sex ratio did not differ from parity, it increased significantly with female body mass and declined with female breeding date, but was independent of the morphology and display (song) behavior (correlates of reproductive success) of social males and EP sires. Male offspring were significantly heavier than female offspring at fledging. Moreover, the probability that male offspring were resighted in subsequent years declined with breeding date, and was greater in replacement clutches, but lower when clutch size was large. Probability of resighting female offspring varied annually, but was independent of all other variables. Given that variance in reproductive success of male kingbirds is much greater than that of females, and that male offspring are more expensive to produce and have a higher probability of recruitment if fledged early in the season, our results support predictions of sex allocation theory: high-quality (heavy) females breeding when conditions were optimal for male recruitment produced an excess of sons.
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Lifetime Reproductive Success of Female Eastern Kingbirds (Tyrannus Tyrannus): Influence of Lifespan, Nest Predation, and Body Size
The Auk, 2007Co-Authors: Michael T. MurphyAbstract:AbstractI report on the lifetime reproductive success (LRS) of female Eastern Kingbirds (Tyrannus Tyrannus) in central New York. I investigated the major correlates of LRS and specifically tested the hypothesis that small body size yields reproductive benefits. Lifetime reproductive success varied widely: 15–20% of females failed to fledge young over their life, whereas 50% of young were fledged by 20% of females. Female lifespan varied between one and eight years, and females that died after one breeding season tended to be smaller-bodied than long-lived females (≥2 seasons). I therefore conducted analyses of LRS for the entire sample and for longer-lived females separately. As in other species, lifespan was the strongest predictor of LRS, followed by the proportion of eggs laid that resulted in fledged young (P). Lifetime reproductive success varied positively with clutch size and, as predicted, inversely with body size (i.e., tarsus length) of females. However, variance partitioning indicated that most variation in LRS was attributable to the effects of lifespan and P, but that a substantial negative covariance existed between lifespan and P. The latter result was consistent with experimental evidence of a cost of reproduction in Eastern Kingbirds. Analysis of the correlates of lifespan, P, and clutch size showed that over a female's lifetime, (1) the longest-lived birds fledged an intermediate proportion of the eggs that they laid, (2) the most productive birds were of intermediate wing length, and (3) females with small tarsi produced the largest clutches and lost the fewest nests to predators. Hence, although lifespan was the dominant influence on LRS, negative effects of large female size appeared to be expressed through the influence of body size on other demographic parameters that contribute to LRS.Éxito Reproductivo Completo de Vida de Hembras de Tyrannus Tyrannus: Influencia de la Duración de la Vida, la Depredación de Nidos y el Tamaño Corporal
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lifetime reproductive success of female eastern kingbirds Tyrannus Tyrannus influence of lifespan nest predation and body size
The Auk, 2007Co-Authors: Michael T. MurphyAbstract:Abstract I report on the lifetime reproductive success (LRS) of female Eastern Kingbirds (Tyrannus Tyrannus) in central New York. I investigated the major correlates of LRS and specifically tested the hypothesis that small body size yields reproductive benefits. Lifetime reproductive success varied widely: 15–20% of females failed to fledge young over their life, whereas 50% of young were fledged by 20% of females. Female lifespan varied between one and eight years, and females that died after one breeding season tended to be smaller-bodied than long-lived females (≥2 seasons). I therefore conducted analyses of LRS for the entire sample and for longer-lived females separately. As in other species, lifespan was the strongest predictor of LRS, followed by the proportion of eggs laid that resulted in fledged young (P). Lifetime reproductive success varied positively with clutch size and, as predicted, inversely with body size (i.e., tarsus length) of females. However, variance partitioning indicated that mos...
Debbie Duffield - One of the best experts on this subject based on the ideXlab platform.
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maternal characteristics and the production and recruitment of sons in the eastern kingbird Tyrannus Tyrannus
Behavioral Ecology and Sociobiology, 2009Co-Authors: Amy C Dolan, Michael T. Murphy, Lucas James Redmond, Debbie DuffieldAbstract:Sex allocation theory predicts that if variance in reproductive success differs between the sexes, females who are able to produce high-quality young should bias offspring sex ratio towards the sex with the higher potential reproductive success. We tested the hypothesis that high-quality (i.e., heavy) female eastern kingbirds (Tyrannus Tyrannus) that bred early in the breeding season would produce male-biased clutches. A significant opportunity for sexual selection also exists in this socially monogamous but cryptically polygamous species, and we predicted that successful extra-pair (EP) sires would be associated with an excess of male offspring. Although population brood sex ratio did not differ from parity, it increased significantly with female body mass and declined with female breeding date, but was independent of the morphology and display (song) behavior (correlates of reproductive success) of social males and EP sires. Male offspring were significantly heavier than female offspring at fledging. Moreover, the probability that male offspring were resighted in subsequent years declined with breeding date, and was greater in replacement clutches, but lower when clutch size was large. Probability of resighting female offspring varied annually, but was independent of all other variables. Given that variance in reproductive success of male kingbirds is much greater than that of females, and that male offspring are more expensive to produce and have a higher probability of recruitment if fledged early in the season, our results support predictions of sex allocation theory: high-quality (heavy) females breeding when conditions were optimal for male recruitment produced an excess of sons.
Kinch Hoekstra - One of the best experts on this subject based on the ideXlab platform.
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Tyrannus rex vs leviathan
Pacific Philosophical Quarterly, 2001Co-Authors: Kinch HoekstraAbstract:Hobbes famously deflates the status of the tyrant, saying that tyranny is no more than monarchy misliked. This formula does not capture the complexities of his treatment of tyranny, however, and markedly fails to explain Hobbes's own employment of the vocabulary of tyranny. Hobbes's criticism and use of the concept of tyranny are examined, and solutions to central puzzles are offered.
Alex E Jahn - One of the best experts on this subject based on the ideXlab platform.
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breeding biology of the white throated kingbird Tyrannus albogularis in brazil and bolivia
The Wilson Journal of Ornithology, 2018Co-Authors: Leonardo Esteves Lopes, Alex E Jahn, Neander M Heming, Dalila De Fatima Ferreira, Omar Barroso Putare, Miguel ângelo MariniAbstract:ABSTRACT The White-throated Kingbird (Tyrannus albogularis) is a widespread species in north-central South America, where it inhabits a variety of open to semi-open habitats. The breeding biology of the species is almost unknown. We describe the reproduction of the species based on 34 nests found in southeastern Brazil and eastern Bolivia since 2004, and eggs and nests found in museum collections. The breeding season lasts from mid-September to mid-February throughout its breeding range. The nest is cup shaped and supported from below. Nests were built with woody stems, grass stems, rootlets, and palm fibers. Mean clutch size was 2.3 eggs, which were ovoid with a pink ground coloration, covered by dark spots and blotches of variable size and color concentrated at the rounded end. The mean incubation period was 16.3 d and the nestling period was 18 d.
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ecological determinants of Tyrannus flycatcher nestling growth at north and south temperate latitudes
The Auk, 2018Co-Authors: Diego T Tuero, Alex E Jahn, Michael S Husak, Diane V Roeder, Diego A Masson, Florencia M Pucheta, Tyler J Michels, Aaron Quickle, Julian Quillen Vidoz, Marisol DominguezAbstract:ABSTRACT An organism's life history strategy is made up of a suite of physiological, behavioral, and ecological traits, which vary at both the interspecific and intraspecific levels in accordance with selective pressures operating on individuals. For birds, 2 primary ecological factors have been proposed to explain intraspecific and interspecific variation in nestling growth: nest predation and food availability. Individual nestling growth rates have important consequences for overall fitness because growth speed could influence subsequent reproductive performance and survival. We studied the relationship between ecological factors (i.e. precipitation level and predation rate) and nestling growth patterns of 2 New World flycatcher species (Tyrannidae) of the genus Tyrannus (Fork-tailed Flycatcher [T. savana] and Scissor-tailed Flycatcher [T. forficatus]) breeding at south- and north-temperate latitudes. We tested the hypothesis that nestling growth rates are driven by nest predation rates and predicted th...
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molting while breeding lessons from new world Tyrannus flycatchers
Journal of Ornithology, 2017Co-Authors: Alex E Jahn, Victor R Cueto, Vanesa Bejarano, Marcela Benavides Guzman, Leone M Brown, Ivan Celso Carvalho Provinciato, Joaquin Cereghetti, Jose I Giraldo, Valentina Gomezbahamon, Michael S HusakAbstract:Songbirds must annually undergo two energetically demanding but important activities: breeding and feather molt. Due to the high energetic investment that each demands, these two events are generally not carried out simultaneously. However, substantial variation in the level of annual reproductive investment among populations may result in variation in molt-breeding overlap between them. With the goal of understanding whether different songbird populations overlap molt and breeding, and, if so, to determine directions for research on the potential tradeoffs involved, we describe the relationship between clutch size, molt, and energetic condition within a genus of New World Flycatchers (Tyrannus). Of 219 Flycatchers sampled, only one individual molted flight feathers while breeding, suggesting that molting flight feathers and breeding simultaneously is too energetically expensive at any clutch size. However, some Flycatchers molted body feathers during the breeding season. When we tested for an effect of clutch size, sex and energetic condition on body molt intensity during the breeding season, only clutch size and sex had significant effects, with a negative effect of clutch size on body molt intensity in males but not in females. Based on these results, we develop a set of hypotheses to guide future studies on the potential tradeoffs between investment in reproduction and molt.
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migration timing and wintering areas of three species of flycatchers Tyrannus breeding in the great plains of north america
The Auk, 2013Co-Authors: Alex E Jahn, Victor R Cueto, Michael S Husak, Diane V Landoll, Jesus Pinto N Ledezma, Heather K Lepage, Douglas J LeveyAbstract:ABSTRACT. Descriptions of intra- and interspecific variation in migratory patterns of closely related species are rare yet valuable because they can help assess how differences in ecology and life-history strategies drive the evolution of migration. We report data on timing and location of migration routes and wintering areas, and on migratory speed and phenology, of Eastern Kingbirds (Tyrannus Tyrannus) from Nebraska and Oklahoma and of Western Kingbirds (T. verticalis) and Scissor-tailed Flycatchers (T. forficatus) from Oklahoma. Eastern Kingbirds primarily departed the breeding site in September, migrating to the Amazon Basin (Bolivia and Brazil), >6,400 km from their breeding site, then used a second wintering site in northwestern South America (Colombia, Ecuador, and Peru) before returning to the breeding site in April. Western Kingbirds left Oklahoma in late July, migrating >1,400 km to northwestern Mexico, then to central Mexico and finally to Central America before returning to Oklahoma in April. ...
Bonnie L. Brown - One of the best experts on this subject based on the ideXlab platform.
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Etiology of ulcerative lesions of Atlantic menhaden (Brevoortia Tyrannus) from James River, Virginia
Parasitology Research, 2005Co-Authors: Stanley R. Webb, Gregory C. Garman, Stephen P. Mcininch, Thomas A. Nerad, Michael T. Peglar, Patrick M. Gillevet, Bonnie L. BrownAbstract:We observed ulcerative lesions on live Atlantic menhaden, Brevoortia Tyrannus , during ichthyofaunal sampling in the tidal James River in October 1999 (near Jamestown, VA, USA). Other synoptically collected fishes exhibited no signs of lesions or pre-ulcerative tissues. Live fish were classified as unremarkable (no dermal anomalies), pre-ulcerative (integument intact with boil-like swelling), and ulcerative (severe focal lesions). Specimens were analyzed for bacteria, fungi, and pathogenic protozoans including amphizoic amoebae, Pfiesteria piscicida , and Kudoa sp. No Pfiesteria were detected in any tissue specimen. All B. Tyrannus examined, including tissues from unremarkable fish, tested positive for presence of the known fish parasite Kudoa . Only ulcerative lesions were also colonized by bacteria, fungi, and amphizoic amoebae. The absence of bacteria, fungi, and protozoans from unremarkable and pre-ulcerative fish suggests that association of other potential pathogens with B. Tyrannus ulcers was due to secondary colonization following lesion formation as a result of Kudoa infection.
