| support for the minimal essential mhc hypothesis: a parrot with a single, highly polymorphic mhc class ii b gene. | we characterized the mhc class ii b gene in the green-rumped parrotlet, forpus passerinus. three approaches were used: polymerase chain reaction amplification using primers complementary to conserved regions of exon 2, sequencing clones from a genomic library, and amplification of exon 2 using species-specific primers. all three methods indicate that there is only a single class ii b locus in this species and no pseudogenes. we suggest that this is the ancestral state for birds. the gene is high ... | 2008 | 18431567 |
| vertical transmission of learned signatures in a wild parrot. | learned birdsong is a widely used animal model for understanding the acquisition of human speech. male songbirds often learn songs from adult males during sensitive periods early in life, and sing to attract mates and defend territories. in presumably all of the 350+ parrot species, individuals of both sexes commonly learn vocal signals throughout life to satisfy a wide variety of social functions. despite intriguing parallels with humans, there have been no experimental studies demonstrating le ... | 2011 | 21752824 |
| opposing selection and environmental variation modify optimal timing of breeding. | studies of evolution in wild populations often find that the heritable phenotypic traits of individuals producing the most offspring do not increase proportionally in the population. this paradox may arise when phenotypic traits influence both fecundity and viability and when there is a tradeoff between these fitness components, leading to opposing selection. such tradeoffs are the foundation of life history theory, but they are rarely investigated in selection studies. timing of breeding is a c ... | 2013 | 24003118 |
| factors shaping the ontogeny of vocal signals in a wild parrot. | parrots rely heavily on vocal signals to maintain their social and mobile lifestyles. we studied vocal ontogeny in nests of wild green-rumped parrotlets (forpus passerinus) in venezuela. we identified three successive phases of vocal signaling that corresponded closely to three independently derived phases of physiological development. for each ontogenetic phase, we characterized the relative importance of anatomical constraints, motor skills necessary for responding to specific contexts of the ... | 2013 | 23038735 |
| dispersal polymorphisms from natal phenotype-environment interactions have carry-over effects on lifetime reproductive success of a tropical parrot. | we examined how interactions between an individual's phenotype and its environment affect natal dispersal at multiple scales and the effects on lifetime reproductive success using a 22-year study of green-rumped parrotlets (forpus passerinus). dispersal increased or decreased lifetime reproductive success depending upon an individual's natal environment and phenotype. many of the phenotypic traits and environmental conditions that influenced lifetime reproductive success also influenced dispersa ... | 2012 | 22906164 |
| predation and infanticide influence ideal free choice by a parrot occupying heterogeneous tropical habitats. | the ideal free distribution (ifd) predicts that organisms will disperse to sites that maximize their fitness based on availability of resources. habitat heterogeneity underlies resource variation and influences spatial variation in demography and the distribution of populations. we relate nest site productivity at multiple scales measured over a decade to habitat quality in a box-nesting population of forpus passerinus (green-rumped parrotlets) in venezuela to examine critical ifd assumptions. v ... | 2010 | 20135326 |
| demographic origins of skewed operational and adult sex ratios: perturbation analyses of two-sex models. | skewed sex ratios - operational (osr) and adult (asr) - arise from sexual differences in reproductive behaviours and adult survival rates due to the cost of reproduction. however, skewed sex-ratio at birth, sex-biased dispersal and immigration, and sexual differences in juvenile mortality may also contribute. we present a framework to decompose the roles of demographic traits on sex ratios using perturbation analyses of two-sex matrix population models. metrics of sensitivity are derived from an ... | 2009 | 19143825 |
| egg mass in an asynchronously hatching parrot: does variation offset constraints imposed by laying order? | life history theory predicts phenotypic trade-offs between the number and quality of offspring produced. intraspecific variation in egg mass is common in birds and increased egg size can have positive effects on offspring fitness. however, evidence of a trade-off with clutch size is limited. we analyzed variation in mass of 5,743 green-rumped parrotlet (forpus passerinus) eggs laid over 15 years to evaluate the potential for facultative adjustment of egg mass and factors governing variation. hea ... | 2005 | 15800736 |
| assessing parental effort in a neotropical parrot: a comparison of methods. | various behavioural or body condition indices are frequently used to measure avian parental effort. to determine which of the indices provide meaningful short-term assessments of parental effort, we used four of them concurrently on breeding green-rumped parrotlets, forpus passerinus, and then compared the results with field metabolic rate (fmr) measurements obtained using the doubly labelled water (dlw) technique. nest provisioning rate correlated significantly with fmr among both males and fem ... | 1999 | 10053073 |
| polymorphic trinucleotide microsatellite loci for a neotropical parrot, the green-rumped parrotlet, forpus passerinus. | | 1998 | 9734079 |
| social constraints on the onset of incubation in a neotropical parrot: a nestbox addition experiment | we examined whether the early onset of incubation serves to protect eggs from the dangers imposed by conspecifics in the green-rumped parrotlet, forpus passerinus, a small neotropical parrot that lays a large clutch and begins incubation on the first egg. nestboxes with eggs were installed and their fate was followed for 72 h to determine whether egg destruction and nest site take-overs occurred as predicted by the egg protection and limited breeding opportunities hypotheses, or whether addition ... | 1998 | 9480668 |
| ontogeny of the adrenocortical response in an extremely altricial bird. | life history theory predicts that physiological and behavioral responsiveness to stress should be delayed in development until the benefits of heightened reactivity outweigh the costs of potentially chronic glucocorticoid levels. birds often acquire stress-responsiveness at locomotor independence, however, both stress-responsiveness and locomotor ability are delayed in birds with altricial developmental strategies. parrots (psittacidae) are extremely altricial, but it is not known whether they a ... | 2019 | 31545013 |