PMID(sorted ascending)
anterior forebrain pathway is needed for stable song expression in adult male white-crowned sparrows (zonotrichia leucophrys).the anterior forebrain pathway of the avian song system is involved in juvenile song learning, but its function in adult song behavior is not known. this report uses lesions to study the role of a particular forebrain nucleus, iman, in the seasonal regeneration of song in adult white-crowned sparrows (zonotrichia leucophrys oriantha). white-crowned sparrows, even when acoustically isolated as juveniles, crystallize a single song which they maintain throughout adulthood. the lateral portion of th ...19989821550
a species-specific acoustic cue for selective song learning in the white-crowned 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, näive 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 univers ...200011007638
a preference for own-subspecies' song guides vocal learning in a song many song birds, males develop their songs as adults by imitating the songs of one or more tutors, memorized previously during a sensitive phase early in life. previous work using two assays, the production of imitations by adult males and playback-induced calling by young birds during the sensitive phase for memorization, has shown that song birds can discriminate between their own and other species' songs. herein i use both assays to show that male mountain white-crowned sparrows, zonotrich ...200011078530
cultural and genetic evolution in mountain white-crowned sparrows: song dialects are associated with population structure.bird song often varies geographically within a species; when this geographic variation has distinct boundaries, the shared song types are referred to as song dialects. how dialects are produced and their adaptive significance are longstanding problems in biology, with implications for the role of culture in the evolution and ecology of diverse organisms, including humans. here we test the hypothesis that song dialect, a culturally transmitted trait, is related to the population genetic structure ...200111831670
effects of temperature on photoperiodically induced reproductive development, circulating plasma luteinizing hormone and thyroid hormones, body mass, fat deposition and molt in mountain white-crowned sparrows, zonotrichia leucophrys oriantha.the mountain white-crowned sparrow, zonotrichia leucophrys oriantha, breeds in subalpine meadows throughout many mountainous regions of western north america. mathematical analysis of 20 years of egg-laying dates at tioga pass, california (3030m elevation) indicated a highly predictable breeding season suggesting that precise environmental cues such as the annual change in day length were important for regulating reproductive function. additionally, it appeared that there was sufficient yearly v ...200312679091
immediate early gene response to hearing song correlates with receptive behavior and depends on dialect in a female songbird.stimulus-induced expression of the immediate early gene zenk (egr-1) in the songbird's auditory forebrain presumably depends on the behavioral significance of the stimulus. few studies, however, have quantified both the zenk and behavioral responses to a stimulus in the same individuals. we played conspecific male song of either hatch (local) or foreign dialect to female white-crowned sparrows (zonotrichia leucophrys oriantha) and quantified both the auditory zenk response and their behavioral r ...200312879354
parasite-mediated heterozygote advantage in an outbred songbird population.coevolution with parasites is thought to maintain genetic diversity in host populations. however, while there are sound theoretical reasons to expect heterozygosity and parasite resistance to be related, this pattern has generally been shown only in inbred laboratory and island populations. this leaves doubt as to whether parasite-mediated selection for genetic diversity is in fact a general process. here we show that haematozoan parasite load is linked to two complementary measures of microsate ...200517148140
proximity to a high traffic road: glucocorticoid and life history consequences for nestling white-crowned sparrows.roads have been associated with decreased reproductive success and biodiversity in avian communities and increased physiological stress in adult birds. alternatively, roads may also increase food availability and reduce predator pressure. previous studies have focused on adult birds, but nestlings may also be susceptible to the detrimental impacts of roads. we examined the effects of proximity to a road on nestling glucocorticoid activity and growth in the mountain white-crowned sparrow (zonotri ...201121712039
effects of experimentally elevated traffic noise on nestling white-crowned sparrow stress physiology, immune function and life history.roads have been associated with behavioral and physiological changes in wildlife. in birds, roads decrease reproductive success and biodiversity and increase physiological stress. although the consequences of roads on individuals and communities have been well described, the mechanisms through which roads affect birds remain largely unexplored. here, we examine one mechanism through which roads could affect birds: traffic noise. we exposed nestling mountain white-crowned sparrows (zonotrichia le ...201323430998
haemoproteus infected birds have increased lifetime reproductive success.the impact of haematozoan infection on host fitness has received substantial attention since hamilton and zuk posited that parasites are important drivers of sexual selection. however, short-term studies testing the assumption that these parasites consistently reduce host fitness in the wild have produced contradictory results. to address this complex issue, we conducted a long-term study examining the relationship between naturally occurring infection with haemoproteus and plasmodium, and lifet ...201525800822
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