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"Sparrows."
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Low-quality birds do not display high-quality signals: The cysteine-pheomelanin mechanism of honesty
The mechanisms that make that the costs of producing high-quality signals are unaffordable to low-quality signalers are a current issue in animal communication. The size of the melanin-based bib of male house sparrows Passer domesticus honestly signals quality. We induced the development of new bibs while treating males with buthionine-sulfoximine (BSO), a substance that depletes the levels of the antioxidant glutathione (GSH) and the amino acid cysteine, two elements that switch melanogenesis from eumelanin to pheomelanin. Final bib size is negatively related to pheomelanin levels in the bib feathers. BSO reduced cysteine and GSH levels in all birds, but improved phenotypes (bibs larger than controls) were only expressed by high-quality birds (BSO birds with largest bibs initially). Negative associations between final bib size and cysteine levels in erythrocytes, and between pheomelanin and cysteine levels, were observed in high-quality birds only. These findings suggest that a mechanism uncoupling pheomelanin and cysteine levels may have evolved in low-quality birds to avoid producing bibs of size not corresponding to their quality and greater relative costs. Indeed, greater oxidative stress in cells was not observed in low-quality birds. This may represent the first mechanism maintaining signal honesty without producing greater relative costs on low-quality signalers.
Journal Article
The triumphant tale of the house sparrow
In picture-book format, presents the history of the house sparrow from its beginnings in the Middle East to its spread with the growth of agriculture around the world, and discusses its population decline in recent years.
Book
Mesozoic retroposons reveal parrots as the closest living relatives of passerine birds
The relationships of passerines (such as the well-studied zebra finch) with non-passerine birds is one of the great enigmas of avian phylogenetic research, because decades of extensive morphological and molecular studies yielded highly inconsistent results between and within data sets. Here we show the first application of the virtually homoplasy-free retroposon insertions to this controversy. Our study examined ~200,000 retroposon-containing loci from various avian genomes and retrieved 51 markers resolving early bird phylogeny. Among these, we obtained statistically significant evidence that parrots are the closest and falcons the second-closest relatives of passerines, together constituting the Psittacopasserae and the Eufalconimorphae, respectively. Our new and robust phylogenetic framework has substantial implications for the interpretation of various conclusions drawn from passerines as model organisms. This includes insights of relevance to human neuroscience, as vocal learning (that is, birdsong) probably evolved in the psittacopasseran ancestor, >30 million years earlier than previously assumed.
Zebra finches are passerine birds, but their phylogenetic relationship with non-passerine birds remains controversial. By examining retroposon insertion loci in avian genomes, the authors reveal that parrots are the closest relatives of passerines, which may have implications for understanding the evolution of birdsong.
Journal Article
Sparrow
In Sparrow, award-winning science and natural history writer Kim Todd explores the bird\"s complex history, biology, and literary tradition. Todd describes the difference between Old World sparrows, like the house sparrow, which can nest in a garage or in an airport, and New World sparrows, which often stake their claim to remote islands or meadows in the high Sierra. In addition, she looks at the nineteenth-century Sparrow War in the United States--a battle over the sparrow\"s introduction--which set the stage for decades of discussions of invasive species. She examines the ways in which sparrows have taught us about evolution and the shocking recent decline of house sparrows in cities globally--this disappearance of a bird that seemed hardwired for success remains an ornithological mystery.
Book
Perceived Predation Risk Reduces the Number of Offspring Songbirds Produce per Year
Predator effects on prey demography have traditionally been ascribed solely to direct killing in studies of population ecology and wildlife management. Predators also affect the prey's perception of predation risk, but this has not been thought to meaningfully affect prey demography. We isolated the effects of perceived prédation risk in a free-living population of song sparrows by actively eliminating direct predation and used playbacks of predator calls and sounds to manipulate perceived risk. We found that the perception of predation risk alone reduced the number of offspring produced per year by 40%. Our results suggest that the perception of predation risk is itself powerful enough to affect wildlife population dynamics, and should thus be given greater consideration in vertebrate conservation and management.
Journal Article
A bird watcher's guide to sparrows
Learn how to start a bird watching hobby including the habitats and life cycle of sparrows.
Book
Hormone levels predict individual differences in reproductive success in a passerine bird
Hormones mediate major physiological and behavioural components of the reproductive phenotype of individuals. To understand basic evolutionary processes in the hormonal regulation of reproductive traits, we need to know whether, and during which reproductive phases, individual variation in hormone concentrations relates to fitness in natural populations. We related circulating concentrations of prolactin and corticosterone to parental behaviour and reproductive success during both the pre-breeding and the chick-rearing stages in both individuals of pairs of free-living house sparrows, Passer domesticus. Prolactin and baseline corticosterone concentrations in pre-breeding females, and prolactin concentrations in pre-breeding males, predicted total number of fledglings. When the strong effect of lay date on total fledgling number was corrected for, only pre-breeding baseline corticosterone, but not prolactin, was negatively correlated with the reproductive success of females. During the breeding season, nestling provisioning rates of both sexes were negatively correlated with stress-induced corticosterone levels. Lastly, individuals of both sexes with low baseline corticosterone before and high baseline corticosterone during breeding raised the most offspring, suggesting that either the plasticity of this trait contributes to reproductive success or that high parental effort leads to increased hormone concentrations. Thus hormone concentrations both before and during breeding, as well as their seasonal dynamics, predict reproductive success, suggesting that individual variation in absolute concentrations and in plasticity is functionally significant, and, if heritable, may be a target of selection.
Journal Article
A sparrow's disappearing home
\"A saltmarsh sparrow is looking for a new home. She must find a place with the right plants and must avoid running into windows and loose pets on the beach. Will the sparrow survive and find a new home? This narrative nonfiction title includes a range map, notes on how to help songbirds, further resources, and a glossary\"-- Provided by publisher.
Book
The house sparrow in the service of basic and applied biology
From the northernmost tip of Scandinavia to the southernmost corner of Patagonia, and across six continents, house sparrows (Passer domesticus) inhabit most human-modified habitats of the globe. With over 7,000 articles published, the species has become a workhorse for not only the study of self-urbanized wildlife, but also for understanding life history and body size evolution, sexual selection and many other biological phenomena. Traditionally, house sparrows were studied for their adaptations to local biotic and climatic conditions, but more recently, the species has come to serve as a focus for studies seeking to reveal the genomic, epigenetic and physiological underpinnings of success among invasive vertebrate species. Here, we review the natural history of house sparrows, highlight what the study of these birds has meant to bioscience generally, and describe the many resources available for future work on this species.
Journal Article