Home‐range size of an Andean bird: Assessing the role of physical condition

Abstract

Because space‐use patterns are a key aspect of the ecology and distribution of species, identifying factors associated with variation in size of territories and home ranges has been central to studies on population ecology. Space use might vary in response to extrinsic factors like habitat quality and to intrinsic factors like physical condition and individual aggressiveness. However, the role of these factors has been poorly documented in the tropics, particularly in high‐elevation bird species. We report the home‐range size of a Neotropical Andean bird, the gray‐browed brush finch (Arremon assimilis), and evaluate the role of physical condition in explaining variation in home‐range size among individuals. We performed spot mapping to estimate the home ranges of 14 territorial males in Bogotá, Colombia, using minimum convex polygons (MCP) and 95% kernel density estimators (KDE). The mean home‐range size estimated for the 100% MCP was 0.522 ± 0.305 ha (range = 0.15–1.18 ha), whereas the 95% KDE estimation was 0.504 ± 0.471 ha (range = 0.13–1.88). We calculated the real mass index of each bird as a proxy of physical condition to assess whether individuals in better physical condition had larger home ranges. Because we found no relation between our estimations of physical condition and home‐range size, we conclude that space use in this species might depend more on ecological factors such as habitat quality or neighbor density than on individual traits. Abstract in French is available with online material.

Isolation by resistance explains genetic diversity in theArremonbrushfinches of northern Mesoamerica

“…All environmental layers were downloaded at high resolution (30 arc‐second, approximately 1 × 1 km) with a WGS84 projection, then converted to projected coordinates using the Mexico ITRF2008 Lambert Conformal Conical projection (900 × 900 m resolution). We chose a resolution of 1 km due to the known limited dispersal in the Arremon species complex (Castaño et al, 2019), which may reflect the importance of landscape features impeding gene flow. Geoprocessing, manipulation, and visualization of spatial data were performed using ArcGIS v.10.4.1 (ESRI), QGIS v.3.16.9 (QGIS Development Team), and the following geospatial packages in R: ‘dismo’ v.1.3‐3 (Hijmans et al, 2020), ‘ggmap’ v.3.0.0 (Kahle & Wickham, 2013), ‘ggplot2’ v.3.3.5 (Wickham, 2016), ‘raster’ v3.4‐13 (Hijmans, 2021), ‘rgdal’ v.1.‐23 (Bivand et al, 2021), ‘rgeos’ v. 0.5‐5 (Bivand & Rundel, 2020), and ‘sf’ v.1.0‐2 (Pebesma, 2018).…”

“…Birds are an underrepresented model group in LG studies; this may reflect the underlying assumption that spatial genetic structure will be difficult to detect in birds due to their high vagility (Kozakiewicz et al, 2018). However, bird species that disperse short distances (<15 km) are relatively common (Castaño et al, 2019; Manthey & Moyle, 2015). Furthermore, birds have been shown to be highly sensitive to the availability of forest patches to which they can move (Kozakiewicz et al, 2018) or changing landscapes through time (Buainain et al, 2020; Moreira et al, 2020), providing a chance to study birds under a LG approach.…”

Is the distribution of the Acorn Woodpecker (Melanerpes formicivorus flavigula) associated with oaks and granaries? A local study in an urban area in northern South America

“…To estimate territory size, we used both the Minimum Convex Polygon (MCP) and the Kernel density estimator (KDE) approaches using the R package “adehabitatHR” (Calenge 2006, Castaño et al 2019). MCP consists on circumscribing all the outermost external location points collected (Mohr 1947), which gave us a rough but consistent estimation of the general area encompassed in each territory.…”

A 143 años de la migración de la garza bueyera Bubulcus ibis (Linnaeus, 1758) desde África hacia los Andes

“…La garza bueyera tiene un potencial de dispersión considerable y baja fidelidad a los sitios de reproducción que son características que favorecen a las poblaciones de especies invasoras (Miyuki y Yukihiko, 2018). Al respecto, la dispersión de las crías puede abarcar grandes distancias e incluso miles de kilómetros en direcciones aleatorias, por lo tanto, este comportamiento habría contribuido a que la especie colonice casi todo el planeta (Castaño et al, 2019). La población tiende a aumentar durante las épocas húmedas y, a formar colonias en árboles, arbustos, juncos, en el suelo y, a menudo se quedan en un mismo lugar, como en el caso de los humedales, durante varios años (Carrasco, et al, 2017).…”