Of hummingbirds and helicopters: Hovering costs, competitive ability, and foraging strategies

Wing morphology and flight kinematics profoundly influence foraging costs and the overall behavioral ecology of hummingbirds. By analogy with helicopters, previous energetic studies have applied the momentum theory of aircraft propellers to estimate hovering costs from wing disc loading (WDL), a parameter incorporating wingspan (or length) and body mass. Variation in WDL has been used to elucidate differences either among hummingbird species in nectar-foraging strategies (e.g., territoriality, traplining) and dominance relations or among gender-age categories within species. We first demonstrate that WDL, as typically calculated, is an unreliable predictor of hovering (induced power) costs; predictive power is increased when calculations use wing length instead of wingspan and when actual wing stroke amplitudes are incorporated. We next evaluate the hypotheses that foraging strategy and competitive ability are functions of WDL, using our data in combination with those of published sources. Variation in hummingbird behavior cannot be easily classified using WDL and instead is correlated with a diversity of morphological and physiological traits. Evaluating selection pressures on hummingbird wings will require moving beyond wing and body mass measurements to include the assessment of the aerodynamic forces, power requirements, and power reserves of hovering, forward flight, and maneuvering. However, the WDLhelicopter dynamics model has been instrumental in calling attention to the importance of comparative wing morphology and related aerodynamics for understanding the behavioral ecology of hummingbirds

Changes over 26 Years in the Avifauna of the Bogotá Region, Colombia: Has Climate Change Become Important?

High Neotropical mountains are among the most threatened ecosystems by climate change and this problem could be accentuated in cities where temperatures are higher. However, there are few data of long-term avifaunal changes in Neotropical cities, and the potential impact of climate change has yet to be addressed. Using data from 26 years of Audubon's Christmas Bird Counts (CBCs) in the Bogotá area (ca. 2,600–3,100 m in Colombia's eastern Andes), we analyze long-term changes of the avifauna using linear regressions corrected for species' habitat preferences and compared urban and rural sites. For the CBC we followed the National Audubon Society's methodology in which birds are counted over a 24-h period within a fixed circle 24 km in diameter. We recorded 235 species in the Bogotá circle with an average of 122 spp/year, including 46 boreal migrants, three endemic species, and four endemic subspecies, two globally and four locally threatened species. Species richness was higher in rural than in urban areas and most species were associated with native forest and scrub and wetlands. Among the species that were analyzed for changes in time 31% increased, 20% decreased, and 49% did not change. Strong fluctuations or changes in abundance were more frequent in urban than rural environments. Many of the species that increased or became established during the CBC interval came from lower elevations or the warmer, drier parts of the region beyond the count circle. By contrast, the lower elevational limits moved to higher elevations in several species that decreased. Climate change with its related effects represented the factor associated with the most changes in abundance. Other potential causes were direct human actions, mostly associated with urbanization, and “natural” successional changes in vegetation; predation by feral dogs and cowbird parasitism also affected several species negatively. Observations indicate that these factors will continue into the future, and the effects of climate change and urbanization in particular will probably intensify. The Bogotá CBC has provided much valuable information for Neotropical urban ornithology and its practice should be encouraged in other Latin American cities and should definitely continue in Bogotá for many years to come

A new subspecies of apolinar’s wren (cistothorus apolinari, aves: troglodytidae), an endangered colombian endemic

We describe Cistothorus apolinari hernandezi, subsp. nov. from wet páramo of theSumapaz massif south of Bogotá, Colombia. This form differs from the nominate ofthe wetlands of the Cundinamarca-Boyacá Plateau in size, coloration, ecology, socialstructure and song and appears to be isolated from it by some 1000 m of elevationand different habitat preferences. A second population apparently occurs some 300km further northeast in the Sierra Nevada del Cocuy in Dept. Boyacá but no dataexist for intervening páramos. As a species, C. apolinari is critically endangeredbut the wetland and páramo populations face different threats and require differentconservation strategies; distinguishing the latter population formally helps callattention to this situation

Polinización de las flores de brachyotum (melastomataceae) por dos especies de diglossa (emberizidae)

Por primera vez se registra a aves del género Diglossa (Emberizidae) aparentemente actuando como polinizadores en forma regular y consistente. Esta interacción involucra flores del género Brachyotum (Melastomataceae). supuestamente especializadas para la polinización por colibríes. Se discuten las posibles adaptaciones morfológicas de las flores, y las posibles implicaciones evolutivas para las plantas de este género, de la polinización por Diglossa.We present the first report of Flower-piercers of the genus Diglossa (Emberizidae) apparently regularly and consistently pollinating flowers supposedly specialized for hummingbird pollination, those of the genus Braehyotum (Melastomataceae). The possible morphological adaptations for, and evolutionary implications of, such pollination for these plants, are discussed

Polinización de las flores de brachyotum (melastomataceae) por dos especies de diglossa (emberizidae)

Por primera vez se registra a aves del género Diglossa (Emberizidae) aparentemente actuando como polinizadores en forma regular y consistente. Esta interacción involucra flores del género Brachyotum (Melastomataceae). supuestamente especializadas para la polinización por colibríes. Se discuten las posibles adaptaciones morfológicas de las flores, y las posibles implicaciones evolutivas para las plantas de este género, de la polinización por Diglossa.We present the first report of Flower-piercers of the genus Diglossa (Emberizidae) apparently regularly and consistently pollinating flowers supposedly specialized for hummingbird pollination, those of the genus Braehyotum (Melastomataceae). The possible morphological adaptations for, and evolutionary implications of, such pollination for these plants, are discussed

Aves del departamento de Cundinamarca, Colombia: conocimiento, nuevos registros y vacíos de información

El departamento de Cundinamarca, Colombia, constituye un territorio con variedad de condiciones geográficas y ecosistémicas que hacen de este una de las regiones con mayor diversidad de aves en el país. Se actualizó el listado de aves y se determinaron los cambios en la composición, así como los vacíos de información. Se recopilaron los datos de campo de los autores entre 1990 y 2015, se revisó la literatura y las bases de datos y se consultaron observadores de aves expertos en la región. Fueron registradas 941 especies de las cuales 24 son endémicas, 72 casi endémicas, 1 especie extinta, 39 amenazadas a nivel nacional, 101 migratorias y 45 con migración local o altitudinal. En total, 701 especies fueron registradas por los autores en 45 localidades (48 registros nuevos para el departamento). Se concluye que existen vacíos de información en los límites departamentales, especialmente hacia la región del río Magdalena y los Llanos Orientales. Sin embargo, regiones donde existe mayor muestreo no se encuentran inventariadas en su totalidad, ya que en estas zonas se siguen encontrando nuevas especies de importancia para la ciencia

Aves del departamento de Cundinamarca, Colombia: conocimiento, nuevos registros y vacíos de información

The department of Cundinamarca in Colombia is an area with diverse geographic and ecosystemic characteristics, a condition that makes it one of the regions in the country with highest diversity of birds. This study updates the list of birds in the department, as well as identifies changes in composition and gaps of information, through the recopilation of field data developed by the authors from 1990 to 2015, revision of different papers and databases, and consultation of experienced birdwatchers in the region.We found 941 records of bird species, of which 24 are endemic, 72 near endemic, 1 extinct, 39 nationally threatened, 101 migratory, and 45 present local and/or altitudinal migration. Of the total number of records, 701 correspond to the authors in 45 localities (48 are new records for the department). We note that there are gaps of information in departmental boundaries, especially in the region of the Magdalena River valley and Llanos Orientales. However, regions that have been more extensively sampled are not fully inventoried since new species for science are still being found.El departamento de Cundinamarca, Colombia, constituye un territorio con variedad de condiciones geográficas y ecosistémicas que hacen de este una de las regiones con mayor diversidad de aves en el país. Se actualizó el listado de aves y se determinaron los cambios en la composición, así como los vacíos de información. Se recopilaron los datos de campo de los autores entre 1990 y 2015, se revisó la literatura y las bases de datos y se consultaron observadores de aves expertos en la región. Fueron registradas 941 especies de las cuales 24 son endémicas, 72 casi endémicas, 1 especie extinta, 39 amenazadas a nivel nacional, 101 migratorias y 45 con migración local o altitudinal. En total, 701 especies fueron registradas por los autores en 45 localidades (48 registros nuevos para el departamento). Se concluye que existen vacíos de información en los límites departamentales, especialmente hacia la región del río Magdalena y los Llanos Orientales. Sin embargo, regiones donde existe mayor muestreo no se encuentran inventariadas en su totalidad, ya que en estas zonas se siguen encontrando nuevas especies de importancia para la ciencia

Nuevos registros e inventario de la avifauna de la serranía de las quinchas, un área importante para la conservación de las aves (aica) en colombia

Presentamos y evaluamos nuevos registros de 60 especies de aves para la Serranía de las Quinchas, Boyacá. Catorce de estos registros representan ampliaciones de sus distribuciones conocidas; también presentamos 20 ampliaciones de distribución local para especies ya registradas en la Serranía; incluimos algunos comentarios sobre los registros más importantes. Con la lista completa se hace una evaluación de la avifauna de la Serranía, comparando los tres sitios de estudio, usando los índices ecológicos propuestos por Stiles and amp; Bohórquez. Finalmente, de acuerdo con los criterios definidos para proponer una zona como AICA, resaltamos la importancia de esta región como un área clave donde urge establecer medidas de conservación para preservar una porción importante de la avifauna representativa del valle medio del río Magdalena a lo largo de una gradiente altitudinal

Lista de chequeo de las aves de Colombia: Una síntesis del estado del conocimiento desde Hilty & Brown

The taxonomy and knowledge of the distribution of Colombian avifauna has undergone great changes since the publication of “A Guide to the Birds of Colombia” by Hilty & Brown (1986) to the extent that we are unaware of how many and which species inhabit the Colombian territory. Here, we present a checklist of the birds of Colombia updated to August 2017 with a review of 340 references dealing with the distribution of Colombian birds. In sum, we report 1909 species for continental and insular Colombia, 216 of which have been added mainly since 1986. Although there are new data on distribution from 66% of the Colombian avifauna, most publications (87%) and new records (53%) are concentrated to the west of the Eastern cordillera (trans-Andean region). Based on the data we identify those regions of the country with knowledge gaps, which deserve more interest from researchers. Moreover, we encourage the ornithological community to publish their unpublished data and to improve the evidence supporting future new records for the country.La taxonomía y conocimiento de la distribución de la avifauna colombiana ha sufrido grandes cambios desde la publicación de “A Guide to the Birds of Colombia” por Hilty & Brown (1986), a tal punto que hoy no se sabe con precisión cuántas y cuáles especies de aves existen en el territorio colombiano. Presentamos la lista de chequeo de la avifauna de Colombia a agosto de 2017 con base en la revisión de 340 referencias relacionadas con la distribución de la avifauna colombiana. En total, reportamos 1909 especies de aves para el territorio continental e insular del país, de las cuales 216 han sido adicionadas principalmente a partir de 1986. Aunque existe información novedosa sobre distribución para cerca del 66% de la avifauna colombiana, la mayoría de las publicaciones (87%) y registros (53%) se concentran al occidente de la cordillera Oriental (región transandina). Con base en esta información identificamos aquellas áreas del país con vacíos de conocimiento que ameritan mayor interés por parte de los investigadores. Además, estimulamos a la comunidad ornitológica a publicar la información inédita represada, al igual que mejorar la evidencia que soporta los registros novedosos para el país

Structure of Herpes Simplex Virus Glycoprotein D Bound to the Human Receptor Nectin-1

Binding of herpes simplex virus (HSV) glycoprotein D (gD) to a cell surface receptor is required to trigger membrane fusion during entry into host cells. Nectin-1 is a cell adhesion molecule and the main HSV receptor in neurons and epithelial cells. We report the structure of gD bound to nectin-1 determined by x-ray crystallography to 4.0 Å resolution. The structure reveals that the nectin-1 binding site on gD differs from the binding site of the HVEM receptor. A surface on the first Ig-domain of nectin-1, which mediates homophilic interactions of Ig-like cell adhesion molecules, buries an area composed by residues from both the gD N- and C-terminal extensions. Phenylalanine 129, at the tip of the loop connecting β-strands F and G of nectin-1, protrudes into a groove on gD, which is otherwise occupied by C-terminal residues in the unliganded gD and by N-terminal residues in the gD/HVEM complex. Notably, mutation of Phe129 to alanine prevents nectin-1 binding to gD and HSV entry. Together these data are consistent with previous studies showing that gD disrupts the normal nectin-1 homophilic interactions. Furthermore, the structure of the complex supports a model in which gD-receptor binding triggers HSV entry through receptor-mediated displacement of the gD C-terminal region