bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phylogeny of Titmice (Paridae): II. Species Relationships Based on Sequences of the Mitochondrial Cytochrome-B Gene
Authors: Gill Frank B. , Slikas Beth , Sheldon Frederick H. 
Published: September 2019

AbstractWe present a phylogenetic hypothesis for 40 species in the bird family Paridae, based on comparisons of nucleotide sequences of the mitochondrial cytochrome-b gene. Parids, including tits and chickadees, are an older group than their morphological stereotypy suggests. The longest cytochrome-b distances between species reach 12% in uncorrected divergence. With the exception of one thrasher-like terrestrial tit species of the Tibetan plateau (Pseudopodoces humilis), morphological and ecological stasis have prevailed since the initial parid radiation in the Old World during the mid-Tertiary.All trees support monophyly of the family Paridae, which includes Parus (sensu lato) and the monotypic Oriental genera Sylviparus, Melanochlora, and Pseudopodoces. Within the clade of chickadees and gray tits (Parus, subgenus Poecile), three Old World species, Parus lugubris of the eastern Mediterranean and Balkan regions, P. superciliosus of high elevations in the Himalayas of western China, and P. varius of the Orient are sisters to all other species. The Eurasian crested titmice (subgenus Lophophanes) and North American crested titmice (subgenus Baeolophus) are sister groups. Our data suggest two colonizations of the New World by parids in the late Tertiary. The ancestor of modern Baeolophus colonized North America 4 mya, and the ancestor of all North American chickadees colonized North America 3.5 mya.Phylogénie chez la mésange (Paridés): II. Relations entre les espèces basées sur des séquences du gène mitochondrial cytochrome-b
Molecular Phylogenetic Relationships Among the Geositta Miners (Furnariidae) and Biogeographic Implications for Avian Speciation in Fuego-Patagonia
Authors: Cheviron Z. A. , Capparella Angelo P. , Vuilleumier François 
Published: September 2019

Abstract
Pleistocene glacial cycles have often been hypothesized to provide vicariant mechanisms leading to allopatric speciation in a wide range of southern South American (Fuegian and Patagonian) avian taxa. Few of those biogeographic hypotheses, however, have been rigorously tested using phylogenetic analysis. We examined sequence variation in three mitochondrial gene fragments (cytochrome b, ND2, and ND3) to construct a molecular phylogeny for the South American genus Geositta (Furnariidae) and to test the interrelated hypotheses that Geositta cunicularia and G. antarctica are sister species that originated from a common ancestor while isolated in glacial refugia during Pleistocene glacial events in Fuego-Patagonia. Sequence data were obtained for all 10 currently recognized species of Geositta as well as Geobates poecilopterus and two outgroup taxa (Upucerthia ruficauda and Aphrastura spinicauda). We found levels of sequence divergence among Geositta species to be high, ranging from 7.4% to 16.3%. Our phylogenetic reconstructions clearly indicate relationships among Geositta species that differ considerably from those of traditional Geositta phylogeny. These data also strongly suggest that Geositta, as currently defined, is paraphyletic, with Geobates being embedded within Geositta. Our data do not support the hypothesized sister relationship between G. antarctica and G. cunicularia. Instead, they suggest that Geositta consists of two distinct clades, with antarctica and cunicularia falling into different clades. The high levels of sequence divergence among Geositta species, lack of a sister relationship between cunicularia and antarctica, and placement of Fuego-Patagonian antarctica into a clade consisting of two high-Andean (saxicolina and isabellina) and one coastal-west-slope (maritima) species demonstrate that the evolutionary history of Geositta is much older and far more complex than a simple model of allopatric speciation in glacial refugia would suggest.
Filogenia Molecular del Género Geositta (Furnariidae) e Implicaciones Biogeográficas para la Especiación de la Aves en Tierra del Fuego y Patagonia
Sex Differences in Singing and Duetting Behavior of Neotropical Rufous-and-White Wrens (Thryothorus Rufalbus)
Authors: Mennill Daniel J. , Vehrencamp Sandra L. 
Published: September 2019

AbstractIn many tropical bird species, males and females sing together in coordinated vocal duets. Although studies of duetting present unique opportunities for understanding conflict and cooperation between the sexes, very few investigations describe the similarities and differences between male and female singing behaviors. Here, we present the first detailed account of the singing behavior of Rufous-and-white Wrens (Thryothorus rufalbus), a resident tropical duetting songbird. Male and female songs share a similar structure, yet show pronounced sex differences. Male songs have lower frequency characteristics and more repeated trill syllables, and often sound louder than female songs. Males sing more than females, and only males show elevated song output at dawn. Both males and females have song repertoires. Males have an average repertoire size of 10.8 song types, whereas females have a significantly smaller average repertoire size of 8.5 song types. Although males share proportionately more of their song types with neighbors than females do, both sexes share more song types with nearby individuals than with distant individuals. Breeding partners combine their solo songs to create duets. Duets assume a variety of different forms, ranging from simple, overlapping male and female songs to complex combinations of multiple male and female songs. Most duets (73%) are created by females responding to male song. Males respond to female-initiated duets with shorter latencies than when females respond to male-initiated duets. Each pair sings certain combinations of song types in duets more often than can be explained by random association, which demonstrates that Rufous-and-white Wrens have duet types. The most common duet type was different for each pair. Our results show that Rufous-and-white Wrens have pronounced sex differences in song structure, singing activity, repertoire size, repertoire sharing, and duetting behavior.Diferencias entre Sexos en el Canto y Comportamiento de Dueto en Thryothorus rufalbus
Foraging and Territory Economics of Sexually Dimorphic Purple-Throated Caribs (Eulampis Jugularis) on Three Heliconia Morphs
Authors: Temeles Ethan J. , Goldman Robin S. , Kudla Alexei U. 
Published: September 2019

Abstract
We observed territorial Purple-throated Caribs (Eulampis jugularis) on three Heliconia morphs (H. caribaea and the red-green and green morphs of H. bihai) on the island of St. Lucia, West Indies, to examine how calculated costs and benefits compared with observed patterns of Heliconia use. Across the three years of our study, H. caribaea territories defended by Purple-throated Carib males were significantly smaller in area and had higher densities of flowers than red-green H. bihai territories, and both kinds of Heliconia territories defended by males were smaller and had higher densities of flowers than the green H. bihai territory maintained by a female. In the period (0630 to 1400 hours) during which birds maintained territories, total maintenance costs were more than met by energy obtained from territories, but only 2 of 13 territories provided sufficient nectar to meet birds' energy requirements for 24 h. Birds supplemented their energy intake from Heliconia territories by foraging at flowers in the rainforest canopy, and the percentage of time a territorial bird spent foraging in the canopy was inversely correlated with energy production on its Heliconia territory. The smaller territory areas and higher flower densities of H. caribaea territories lowered males' foraging time and energy costs per flower on H. caribaea as compared with red-green H. bihai territories, theoretically allowing them to meet their energy demands in less time and at lower cost. Males' estimated foraging time and energy costs were greatest at the green morph of H. bihai; compared with females, they would save a higher proportion of time and energy by foraging at H. caribaea and the red-green morph of H. bihai. That asymmetry between males and females in relative gains from foraging at each of the three Heliconia morphs may further reinforce resource partitioning between them, in addition to differences in size and fighting abilities.
Economía de Forrajeo y Territorialidad en la Especie Sexualmente Dimórfica Eulampis jugularis en Tres Formas de Heliconia
Dispersal by Juvenile American Crows (Corvus Brachyrhynchos) Influences Population Dynamics Across a Gradient of Urbanization
Authors: Withey John C. , Marzluff John M. 
Published: September 2019

Abstract
American Crow (Corvus brachyrhynchos) populations are increasing across North America, often at high rates in urban areas. A monthly survey of American Crows in the Seattle Christmas Bird Count (CBC) circle suggested that winter counts reflected American Crow abundance at other times of the year, so we used CBC results for American Crows as a measure of population trend. In the Seattle area, local survival and fecundity appear unable to account for exponential population growth. We tested the hypothesis that juvenile dispersal from outlying suburban and exurban areas contributes to growth in the urban population by radiotagging 56 juveniles 5–46 km away from the central business district of Seattle and tracking their movements. Juvenile American Crows’ centers of activity were 0.2–22.2 km away from their natal territory during the first 3–12 months after fledging. An estimated 45% survived one year. Movements of dispersing American Crows varied in their consistency with simulated random-walk paths; the data suggested that, at the population level, American Crows were not drawn into urban areas, though some individuals may have been. Movements of dispersers produced a net influx into the city, because of greater reproductive success outside the city than in it. Simulations of urban population growth that included immigrants and emigrants accounted for most of the observed growth, which indicates the importance of distant suburban and exurban breeding pairs to urban population dynamics.
La Dispersión de Juveniles de Corvus brachyrhynchos Influencia la Dinámica Poblacional a lo Largo de un Gradiente de Urbanización
Feather-Degrading Bacteria do not Affect Feathers on Captive Birds
Authors: Cristol Daniel A. , Armstrong Jessica L. , Whitaker Justine M. , Forsyth Mark H. 
Published: September 2019

AbstractAttention has recently been focused on microbes that occur in the plumage of wild birds and can degrade feathers under laboratory conditions and in poultry-waste composters. In particular, Bacillus licheniformis, a soil bacterium, was found in the plumage of many birds netted in eastern North America, and poultry feathers were rapidly broken down when incubated in a suspension of this bacterium (Burtt and Ichida 1999). If feather-degrading microbes affect wild birds under normal conditions, they may have played an important role in the evolution of molt, plumage color, and sanitation behavior, such as sunning and preening. We performed the first test on whether a feather-degrading bacterium can degrade feathers of live birds housed outdoors under seminatural conditions. We found no evidence that B. licheniformis degraded wing feathers of Northern Cardinals (Cardinalis cardinalis) when applied twice (with a two-week interval) during the winter, despite the fact that it degraded Northern Cardinal feathers when incubated in our laboratory. In a second experiment, we found no evidence that B. licheniformis degraded feathers of European Starlings (Sturnus vulgaris) when applied twice (with a one-week interval) during the summer, despite the fact that birds were housed in humid conditions that should have favored the growth of B. licheniformis.Las Bacterias que Degradan Plumas no Afectan las Plumas de Aves en Cautiverio
Relationships Among Mercury Concentrations, Hormones, and Nesting Effort of White Ibises (Eudocimus Albus) in the Florida Everglades
Authors: Heath Julie A. , Frederick Peter C. 
Published: September 2019

Abstract
Mercury, a common wetland pollutant, can affect wildlife populations through acute toxicity or through physiological effects that modify behavior and negatively influence reproductive success. We compared body-feather mercury concentrations of free-living male and female adult White Ibises (Eudocimus albus) during three breeding seasons in the Florida Everglades and examined the relationships among mercury, hormone concentrations, and body-condition scores. Female White Ibises consistently had lower mercury concentrations than males. Prebreeding females' estradiol concentrations were negatively correlated with mercury concentrations. However, we found no relationship between mercury and female testosterone, progesterone, and corticosterone concentrations. Incubating male White Ibises showed a significant positive relationship between testosterone and mercury concentrations, but no other significant hormonal correlations with mercury concentrations. We used a seven-year standardized data set of Great Egret (Ardea alba) chick-feather mercury concentrations as a measure of temporal changes in mercury bioavailability in the Everglades and related that measure to annual numbers of White Ibis nests. White Ibis nesting was negatively correlated with the mercury exposure index. Low numbers of nesting White Ibises may have been the result of fewer birds nesting or high abandonment rates. Our results suggest that mercury exposure may cause fewer birds to nest or more birds to abandon nests because of subacute effects on hormone systems. However, the results are correlative; they call for further investigation in free-living populations and in the laboratory.
Relaciones entre las Concentraciones de Mercurio, Hormonas y el Esfuerzo de Nidificación de Eudocimus albus en los Everglades, Florida
Effectiveness of Call-Broadcast Surveys for Monitoring Marsh Birds
Authors: Conway Courtney J. , Gibbs James P. 
Published: September 2019

Abstract
Many species of marsh birds (e.g. rails and bitterns) are believed to be declining in North America, yet we lack an effective monitoring program to estimate their population trends. Broadcast of prerecorded calls to elicit vocalizations is a commonly used method in surveys of marsh birds, but whether gains in detection and index precision outweigh the drawbacks of call-broadcast is unclear. To evaluate the effectiveness of call-broadcast surveys, we pooled marsh-bird survey data from 8,047 point-count surveys contributed by 11 cooperators and compared numbers of birds detected and variation in numbers detected between call-broadcast and passive surveys. For most rails (particularly Virginia Rails [Rallus limicola]), call-broadcast surveys were effective at increasing the detection probability (e.g. average number of Virginia Rails detected per occupied point was 1.25 for call-broadcast surveys and 0.17 for passive surveys). The proportion of points at which no birds were detected was high for all species (range 74–99%) and was slightly lower on call-broadcast surveys as compared with passive surveys. Coefficient of variation (CV) among replicate surveys was higher for passive surveys, particularly for rails (average CV in number of birds detected per point was 209% for passive surveys and 189% for call-broadcast surveys). On the basis of those results, we recommend a marsh-bird monitoring protocol that includes an initial passive period followed by a period of call-broadcast to provide survey data that incorporate the benefits while avoiding the drawbacks of call-broadcast. We also recommend separating both the passive and the call-broadcast periods into 1-min subsegments that will allow estimates of components of detection probability within the monitoring effort.
Efectividad de Censos que Reproducen Vocalizaciones Pregrabadas para Monitorear Aves de Pantano
Molecular Evidence for Recent Radiation in Southern Hemisphere Masked Gulls
Authors: Given Andrew D. , Mills James A. , Baker Allan J. 
Published: September 2019

Abstract
Masked gulls are believed, on the basis of morphological and recent molecular work, to be a monophyletic group within the Laridae, but relationships of species within the group are not well resolved. We used sequence data from four mitochondrial DNA genes (ND2, ND5, ATPase6, and ATPase 8) totaling >3,600 base pairs to clarify relationships among the species and test competing hypotheses about their origin and biogeography. Monophyly of the masked gulls was confirmed. We also found strong support for a clade including all Southern Hemisphere masked gulls as well as a lone Northern Hemisphere representative, the Black-headed Gull (Larus ridibundus). The Australasian taxa form a well-supported clade, in which the Black-billed Gull (L. bulleri) is sister to the Red-billed Gull (L. novaehollandiae scopulinus) of New Zealand and the Australian Silver Gull (L. n. novaehollandiae). Another well-supported clade includes the Black-headed Gull as sister to the South African Hartlaub's Gull (L. hartlaubii) and the Gray-hooded Gull (L. cirrocephalus) of Africa and South America. The strongly supported position of L. ridibundus within the “southern clade” suggests that it originated from a Southern Hemisphere ancestor and recently dispersed into the Northern Hemisphere. Estimates of divergence times using rate-smoothing methods are consistent with those from previous molecular work and suggest that (1) masked gulls diverged from other gulls <2 mya and (2) much of the radiation in the group occurred in the last 600,000 years.
Preuve moléculaire de la radiation récente chez les mouettes “masquées” de l'hémisphère sud
Renesting Determines Seasonal Fecundity in Songbirds: What do we Know? What Should we Assume?
Authors: Grzybowski Joseph A. , Pease Craig M. 
Published: September 2019

AbstractBecause of the difficulty of following female songbirds through an entire breeding season, field ornithologists are seldom able to directly measure seasonal fecundity (defined as number of offspring produced per female during an entire breeding season). Instead, it is more commonly inferred from some measure of nest-productivity data (e.g. average number of offspring fledged per nesting attempt) using algorithms that make assumptions about the propensity of females to renest after a nest failure or after successfully fledging a brood. Recent analyses have often assumed set maximum numbers of nesting attempts and successful broods, and that all females breed up to those maxima. However, whereas data from songbirds intensively followed for an entire breeding season show that they are capable of up to 4–8 nesting attempts, many authors, in estimating seasonal fecundity, assume a maximum of only 1–4 nesting attempts. We applied a model to a Prairie Warbler (Dendroica discolor) data set (Nolan 1978) that allowed direct comparisons of (1) seasonal-fecundity estimates obtained assuming fixed maximum numbers of renestings and broods with (2) estimates obtained assuming that numbers of renesting attempts and successful nests are constrained only indirectly by length of breeding season. Although results under the latter assumption are concordant with Nolan's (1978) direct empirical measure of Prairie Warbler seasonal fecundity, estimates under assumptions of fixed maxima of renestings or broods are in serious error for many parameter choices. As such, our analyses disclose that essentially all estimates of seasonal fecundity in the literature derived by assuming a limited maximum number of nesting attempts or of successful broods are biased. Most commonly, when nest mortality is high, seasonal fecundity is underestimated; in some cases where nest mortality is low, seasonal fecundity is overestimated. We recommend that researchers estimating seasonal fecundity from nest-productivity data use a model that explicitly sets breeding-season length and thereby only indirectly constrains the possible number of nesting attempts and successful broods.La Nidificación Repetida Determina la Fecundidad Estacional en las Aves Canoras: ¿Qué Sabemos? ¿Qué Deberíamos Suponer?
Relationship Between Mayfield Nest-Survival Estimates and Seasonal Fecundity: A Cautionary Note
Authors: Jones Jason , Doran Patrick J. , Nagy Laura R. , Holmes Richard T. 
Published: September 2019

AbstractEstimates of nest survival are commonly used as indices of reproductive productivity in a wide range of studies, including examinations of population dynamics, habitat fragmentation, and wildlife management. However, the strength of the relationship between estimates of nest survival and of seasonal fecundity has rarely been tested. To examine that relationship, we used 16 years of demographic data from an intensively studied population of individually marked Black-throated Blue Warblers (Dendroica caerulescens). We found a positive relationship between Mayfield nest-survival estimates and seasonal fecundity (i.e. number of fledglings produced per female). However, seasonal-fecundity predictions based on nestsurvival values underestimated observed seasonal fecundity by an average of 33% and population growth rate by 20%. Our results suggest that, though nest-survival estimates may be useful as indices of pressures on a population (e.g. nest predation), care is needed in using them as the basis of conservation or management strategies or to make inferences about population-level processes.Relación entre las Estimaciones de Supervivencia de Nidos de Mayfield y la Fecundidad Estacional: una Nota de Cautela
Is Nest Predation by Steller's Jays (Cyanocitta Stelleri) Incidental or the Result of a Specialized Search Strategy?
Authors: Vigallon Stacey M. , Marzluff John M. 
Published: September 2019

Abstract
Decreased nest success and elevated levels of nest predation have been linked to changes in landscape configuration and increased edge. However, our current understanding of the mechanics of nest predation is limited. Using radiotelemetry and artificial nest experiments, we studied the ranging and nest-predation behavior of the Steller's Jay (Cyanocitta stelleri) in the managed forests of western Washington. Steller's Jays used a variety of forest seral stages, 95% of foraging observations occurred within 50 m of edges, and home range did not appear to be influenced by breeding success. Predation on artificial nests was elevated in high-use areas of home ranges, which suggests that Steller's Jays find nests incidentally while foraging for primary prey (insects). Steller's Jays did not appear to use a specialized search strategy to find nests, though they had a search image for nests and were capable of performing area-restricted searching for other food items (peanuts). To assess the risk of nest predation by Steller's Jays, it may be useful for managers to survey areas of concern for Steller's Jays and their foods. By equating relative abundance of Steller's Jays with nest predation risk, managers can then map predation risk onto the landscape of concern at the scale of the management unit.
¿Es la Depredación de Nidos por Cyanocitta stelleri Incidental o es el Resultado de una Estrategia de Búsqueda Especializada?