| factors influencing song development in the white-crowned sparrow (zonotrichia leucophrys). | nestling white-crowned sparrows (zonotrichia leucophrys nuttalli) were hand-reared in sound-isolation chambers under a variety of conditions. the songs of total isolates were compared with songs of birds tutored with song, and the number of inputs sufficient for a bird to produce a normal song was explored. the flexibility of the song learning system was investigated with a range of tape-recorded tutor songs: alien dialects, alien subspecies, alien species, alternating alien dialects, and an abe ... | 2013 | 3979027 |
| patterns of song across natural and anthropogenic soundscapes suggest that white-crowned sparrows minimize acoustic masking and maximize signal content. | soundscapes pose both evolutionarily recent and long-standing sources of selection on acoustic communication. we currently know more about the impact of evolutionarily recent human-generated noise on communication than we do about how natural sounds such as pounding surf have shaped communication signals over evolutionary time. based on signal detection theory, we hypothesized that acoustic phenotypes will vary with both anthropogenic and natural background noise levels and that similar mechanis ... | 2016 | 27128443 |
| annual hematocrit profiles in two subspecies of white-crowned sparrow: a migrant and a resident comparison. | 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 ... | 2016 | 27082524 |
| changes in plasma concentrations of progesterone, dehydroepiandrosterone and corticosterone in response to acute stress of capture, handling and restraint in two subspecies of white-crowned sparrows. | the aim of this study was to determine circulating patterns of the three major adrenal steroids in blood in response to stress during acute restraint handling in two subspecies of white-crowned sparrow. gambel's white-crowned sparrows (zonotrichia leucophrys gambelii) are long distance migrants that breed at high latitudes and nuttall's white-crowned sparrows (zonotrichia leucophrys nuttalli) are residents of coastal california. column partition chromatography was developed to separate progester ... | 2014 | 25072921 |
| on the evolution of brain size in relation to migratory behaviour in birds. | migratory birds appear to have relatively smaller brain size compared to sedentary species. it has been hypothesized that initial differences in brain size underlying behavioural flexibility drove the evolution of migratory behaviour; birds with relatively large brains evolved sedentary habits and those with relatively small brains evolved migratory behaviour (migratory precursor hypothesis). alternative hypotheses suggest that changes in brain size might follow different behavioural strategies ... | 2007 | 18311316 |
| song learning and vocal tradition in nuttall's white-crowned sparrows. | we investigated song sharing and dispersion of song types in the wild in a colour-marked population of the non-migratory nuttall's white-crowned sparrow, zonotrichia leucophrys nuttalli. the songs of fathers, their male progeny (sons), and the neighbours of the sons at recruitment sites were analysed spectrographically and compared qualitatively and quantitatively. to determine whether a son's song more closely matched that of his father or a neighbour at the site settled, we subjected frequency ... | 1998 | 9632480 |
| seasonal plasticity of the song control system in wild nuttall's white-crowned sparrows. | seasonal plasticity in the morphology of telencephalic nuclei that control song behavior has been reported for diverse species of songbirds. the only published report of a lack of seasonal changes in the song nuclei of a seasonally breeding bird is that of baker et al. in the nuttall's subspecies of white-crowned sparrow (zonotrichia leucophrys nuttalli). in this study, they brought wild birds into the laboratory and exposed them to either "summer" or "winter" photoperiods. previous studies have ... | 1998 | 9469619 |
| song dialects and gene flow in the white-crowned sparrow, zonotrichia leucophrys nuttalli. | | 1985 | 28561976 |
| song dialects as barriers to dispersal in white-crowned sparrows, zonotrichia leucophrys nuttalli. | | 1978 | 28567938 |
| white-crowned sparrows (zonotrichia leucophrys nuttalli) to song. | the pattern of responses of both male and female white-crowned sparrows to playback of recorded song depends on whether the female has eggs, nestlings, or fledglings, and on the behavior under consideration. these patterns can be understood in the context of the behavior patterns appropriate during each of the different stages of the reproductive cycle. | 1976 | 17838460 |