Ecogeographical and climatic predictors of geographical variation in plumage and morphology in rufous-capped warblers, Basileuterus rufifrons

Many broadly distributed species exhibit geographic variation across their range. Intraspecific variation across geographical ranges can allow us to test ecological and sexual selection hypotheses that may help explain this variation. In this study, we quantified geographical variation in morphology and plumage colouration of rufous-capped warblers (Basileuterus rufifrons), a broadly distributed Neotropical passerine bird ranging from northern Mexico to northern South America. We measured morphological characteristics and plumage colouration of 473 museum specimens covering the entirety of the species’ range, and compared these with geographic location and climate data obtained from the WorldClim data base and the University of Idaho Climatology Lab. If variation in body size, measured by wing length, follows Bergman’s rule, we expect it to increase with latitude; whereas if body size follows Allen’s rule, we expect extremities to shorten at higher latitudes. If plumage colouration follows Gloger’s rule, we expect plumage colouration to become darker in more humid climates, whereas if it is limited by the availability of nutrients, we expect brighter plumage colour in habitats with greater primary productivity. If sexual selection drives divergence in male and female body size and colouration, we expect birds in northern populations to exhibit greater sexual dimorphism and dichromatism and to exhibit more contrast against the vegetation background than southern populations, where male and female sex roles are expect to converge in more tropical areas. Data analyses are still in progress. Our research of geographical variation in rufous-capped warblers will help us better understand the relative importance of ecogeographical rules and the influence on sexual selection geographic variation, and may help us predict how animals could respond to future changes in environmental conditions

Repertoire structure, song sharing, reproductive success, and territory tenure in a population of Canada Warblers (Cardellina canadensis) in central New Hampshire

Sexual selection for larger repertoires and the social advantages of sharing songs with territorial neighbours are two forces which may drive the evolution of complex song repertoires in songbirds. To evaluate the influence of these two selective pressures on repertoire evolution in a species with a complex repertoire, we examined repertoire structure, song sharing, reproductive success, and territory tenure in a Canada Warbler (Cardellina canadensis (L., 1766)) population in New Hampshire. Over two breeding seasons, we recorded 63 singing males, classified their song repertoires, quantified male song sharing, and determined male reproductive success and territory tenure. Male Canada Warblers had complex repertoires averaging 12 phrases (particular sequences of song elements) and 55 variants (songs composed of particular sequences of phrases). Song sharing decreased significantly with distance between territories, all of which wereThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

FIGURE 1 in Phenotypic variation and vocal divergence reveals a species complex in White-eared Ground-sparrows (Cabanis) (Aves: Passerellidae)

FIGURE 1. Map of the distribution of the Melozone leucotis subspecies from southern Mexico to Costa Rica, based on data from Stiles & Skutch (1989), Howell & Webb (1995), and Rising (2011). Melozone l. occipitalis is separated from M. l. nigrior by at least 370 km, and M. l. nigrior is separated from M. l. leucotis by at least 250 km

Phenotypic variation and vocal divergence reveals a species complex in White-eared Ground-sparrows (Cabanis) (Aves: Passerellidae)

The taxonomy of the genus Melozone has recently been analyzed from genus to subspecies level, leading to a significant revision of our understanding of this group of birds. Previous studies quantified differences in phenotypic traits, behavior, and genotypes, to provide a better understanding of the underappreciated diversity within Melozone and the relationship between species within this genus. Yet the relationship between the subspecies of White-eared Ground-sparrows, Melozone leucotis, has not received thorough taxonomic scrutiny. In this study, we evaluate the taxonomic status of the three recognized subspecies of M. leucotis using multiple morphometric characteristics, plumage color features, and vocalizations. We measured plumage patterns and reflectance from museum specimens, morphometric features from museum specimens and live birds, and vocal characteristics from sound recordings. We observed substantial variation between subspecies in plumage, morphometry, and voice, especially between northern and southern birds. The phenotypic and vocal differences exhibited by M. l. occipitalis (from Chiapas, Mexico; Guatemala; and El Salvador) suggest that its taxonomic relationship with the M. l. leucotis and M. l. nigrior complex (from Costa Rica and Nicaragua, respectively) needs to be reevaluated, because these two groups are highly diagnosable from one another. Additionally, M. l. occipitalis is geographically isolated from the other two subspecies, reducing the probability of contact by natural causes in the near future. Based on the clear differences in voice, plumage, and morphometric features reported here, we propose that M. l. occipitalis be recognized as a distinct species, M. occipitalis (Salvin's Ground-sparrow), diagnosed on the basis of its longer tail, longer bill, duller plumage, and songs with a lower frequency of maximum amplitude.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí