| experimental infection of california birds with western equine encephalomyelitis and st. louis encephalitis viruses. | a total of 27 bird species from the san joaquin and coachella valleys of california were inoculated subcutaneously with sympatric strains of western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses. overall, 133 of 164 birds inoculated with wee virus developed a viremia detected by plaque assay; significantly greater than 72 of 163 birds inoculated with sle virus. host competence was calculated as the average number of days that each avian species had a viremia > or = 2 lo ... | 2003 | 14765678 |
| does feeding on infected mosquitoes (diptera: culicidae) enhance the role of song sparrows in the transmission of arboviruses in california? | song sparrows, melopiza melodia, inoculated subcutaneously with either western equine encephalomyelitis virus (family togaviridae, genus alphavirus, weev) or west nile virus (family flaviviridae, genus flavivirus, wnv) developed elevated viremias, and they were considered to be competent experimental hosts for both viruses. however, birds that ingested from three to 20 mosquitoes containing comparable amounts of either weev or wnv failed to become infected, indicating limited oral susceptibility ... | 2007 | 17427703 |
| habitat selection, acoustic adaptation, and the evolution of reproductive isolation. | we examined barriers to gene flow in a hybrid zone of two subspecies of the song sparrow (melospiza melodia). we focused on how mating signals and mate choice changed along an environmental gradient and gathered data on the morphology, genetics, ecology, and behavior across the zone. melospiza m. heermanni of the pacific slope of california and m. m. fallax of the sonoran desert, each distinct in plumage, meet across a steep environmental gradient in southeastern california. although both subspe ... | 2004 | 15562681 |
| population differences in fever and sickness behaviors in a wild passerine: a role for cytokines. | immune responses benefit hosts by clearing pathogens, but they also incur physiological costs and tissue damage. while wild animals differ in how they balance these costs and benefits, the physiological mechanisms underlying such differential investment in immunity remain unknown. uncovering these mechanisms is crucial to determining how and where selection acts to shape immunological defense. among free-living song sparrows (melospiza melodia) in western north america, sickness-induced lethargy ... | 2010 | 21075952 |
| the influence of the california marine layer on bill size in a generalist songbird. | the hypothesis is tested that birds in hotter and drier environments may have larger bills to increase the surface area for heat dissipation. california provides a climatic gradient to test the influence of climate on bill size. much of california experiences dry warm/hot summers and coastal areas experience cooler summers than interior localities. based on measurements from 1488 museum skins, song sparrows showed increasing body-size-corrected bill surface area from the coast to the interior an ... | 2012 | 23206140 |
| climate, ecological release and bill dimorphism in an island songbird. | sexual size dimorphism is expected to be more pronounced in vertebrates on islands, particularly in trophic characters, as a response to decreased interspecific competition for food. we found (based on measurements of 1423 museum specimens) that bill size dimorphism was greater in island than mainland populations of song sparrows. however, dimorphism varied among islands and was positively correlated with high summer temperature and island size. island song sparrow bills follow the overall posit ... | 2013 | 23616645 |