| pathology associated with west nile virus infections in the yellow-billed magpie (pica nuttalli): a california endemic bird. | yellow-billed magpies (pica nuttalli, corvidae) are found exclusively in central california and have experienced alarming west nile virus (wnv)-associated mortality since 2004. the first reported case of wnv in the species was reported in july 2004. subsequently, 81% (304/374) of dead magpies submitted that year to the california department of health services dead bird surveillance program were wnv positive by polymerase chain reaction (pcr) test. we studied 43 magpie carcasses collected in 2004 ... | 2010 | 20688633 |
| efficacy of three vaccines in protecting western scrub-jays (aphelocoma californica) from experimental infection with west nile virus: implications for vaccination of island scrub-jays (aphelocoma insularis). | abstract the devastating effect of west nile virus (wnv) on the avifauna of north america has led zoo managers and conservationists to attempt to protect vulnerable species through vaccination. the island scrub-jay (aphelocoma insularis) is one such species, being a corvid with a highly restricted insular range. herein, we used congeneric western scrub-jays (aphelocoma californica) to test the efficacy of three wnv vaccines in protecting jays from an experimental challenge with wnv: (1) the fort ... | 2011 | 21438693 |
| surveillance for west nile virus and vaccination of free-ranging island scrub-jays (aphelocoma insularis) on santa cruz island, california. | abstract transmission of west nile virus (wnv) on mainland california poses an ongoing threat to the island scrub-jay (issj, aphelocoma insularis), a species that occurs only on santa cruz island, california, and whose total population numbers <5000. our report describes the surveillance and management efforts conducted since 2006 that are designed to understand and mitigate for the consequences of wnv introduction into the issj population. we suspect that wnv would most likely be introduced to ... | 2011 | 21438695 |
| partial support for the central-marginal hypothesis within a population: reduced genetic diversity but not increased differentiation at the range edge of an island endemic bird. | large-scale population comparisons have contributed to our understanding of the evolution of geographic range limits and species boundaries, as well as the conservation value of populations at range margins. the central-marginal hypothesis (cmh) predicts a decline in genetic diversity and an increase in genetic differentiation toward the periphery of species' ranges due to spatial variation in genetic drift and gene flow. empirical studies on a diverse array of taxa have demonstrated support for ... | 2017 | 28327578 |
| context-dependent seed dispersal by a scatter-hoarding corvid. | corvids (crows, jays, magpies and nutcrackers) are important dispersers of large-seeded plants. studies on captive or supplemented birds suggest that they flexibly adjust their scatter-hoarding behaviour to the context of social dynamics and relative seed availability. because many corvid-dispersed trees show high annual variation in seed production, context-dependent foraging can have strong effects on natural corvid scatter-hoarding behaviour. we investigated how seed availability and social d ... | 2016 | 26876417 |
| an open-population hierarchical distance sampling model. | modeling population dynamics while accounting for imperfect detection is essential to monitoring programs. distance sampling allows estimating population size while accounting for imperfect detection, but existing methods do not allow for estimation of demographic parameters. we develop a model that uses temporal correlation in abundance arising from underlying population dynamics to estimate demographic parameters from repeated distance sampling surveys. using a simulation study motivated by de ... | 2015 | 26240853 |
| islands within an island: repeated adaptive divergence in a single population. | physical barriers to gene flow were once viewed as prerequisites for adaptive evolutionary divergence. however, a growing body of theoretical and empirical work suggests that divergence can proceed within a single population. here we document genetic structure and spatially replicated patterns of phenotypic divergence within a bird species endemic to 250 km(2) santa cruz island, california, usa. island scrub-jays (aphelocoma insularis) in three separate stands of pine habitat had longer, shallow ... | 2015 | 25645813 |
| hierarchical distance-sampling models to estimate population size and habitat-specific abundance of an island endemic. | population size and habitat-specific abundance estimates are essential for conservation management. a major impediment to obtaining such estimates is that few statistical models are able to simultaneously account for both spatial variation in abundance and heterogeneity in detection probability, and still be amenable to large-scale applications. the hierarchical distance-sampling model of j. a. royle, d. k. dawson, and s. bates provides a practical solution. here, we extend this model to estimat ... | 2012 | 23210315 |
| spatially biased dispersal of acorns by a scatter-hoarding corvid may accelerate passive restoration of oak habitat on california's largest island. | scatter hoarding by corvids (crows, jays, magpies, and nutcrackers) provides seed dispersal for many large-seeded plants, including oaks and pines. when hoarding seeds, corvids often choose nonrandom locations throughout the landscape, resulting in differential survival of seeds. in the context of habitat restoration, such disproportional storing of seeds in areas suitable for germination and establishment can accelerate expansion and recovery of large-seeded tree populations and their associate ... | 2017 | 29491996 |