Individual and spatio-temporal variations in the home range behaviour of a long-lived, territorial species

Abstract

Despite the fact that investigations of home range behaviour have exponentially evolved on theoretical, analytical and technological grounds, the factors that shape animal home range behaviour still represent an unsolved question and a challenging field of research. However, home range studies have recently begun to be approached under a new integrated conceptual framework, considering home range behaviour as the result of the simultaneous influences of temporal, spatial and individual-level processes, with potential consequences at the population level. Following an integrated approach, we studied the influence of both external and internal factors on variations in the home range behaviour of 34 radiotagged eagle owl (Bubo bubo) breeders. Home range behaviour was characterised through complementary analysis of space use, movement patterns and rhythms of activity at multiple spatio-temporal scales. The effects of the different phases of the biological cycle became considerably evident at the level of movement patterns, with males travelling longer distances than females during incubation and nestling periods. Both external (i.e. habitat structure and composition) and internal (i.e. sex and health state) factors explained a substantial amount of the variation in home range behaviour. At the broader temporal scale, home range and core area size were negatively correlated with landscape heterogeneity. Males showed (1) smaller home range and core area sizes, (2) more complex home range internal structure and (3) higher rates of movement. The better the physiological condition of the individuals, the simpler the internal home range structure. Finally, inter- and intra-individual effects contributed to shaping space use and movement patterns during the biological cycle. Because of the plurality of behavioural and ecological processes simultaneously involved in home range behaviour, we claim that an integrative approach is required for adequate investigation of its temporal and spatial variation.

Using risk prediction models and species sensitivity maps for large-scale identification of infrastructure-related wildlife protection areas: The case of bird electrocution

“…The nesting area value was applied only to the 1 km × 1 km grid sections where the nest was located. The home range radius sizes were assigned according to annual home range studies carried out close to our study area as follows: golden eagle, 5 km (Fraguas et al, 2001); Bonelli's eagle, 4 km (Sanz et al, 2005;Pérez-García et al, 2013); and Eurasian eagle owl, 2 km (Delgado et al, 2009;Campioni et al, 2013). For griffon vulture, we considered only a protection area of 1 km around colonies because of the vast home range associated with this species (> 4000 km 2 , García-Ripollés et al, 2011, Zuberogoitia et al, 2012.…”

Post-fledging Dependence Period and Onset of Natal Dispersal in Bearded Vultures (Gypaetus barbatus): New Insights from GPS Satellite Telemetry

“…For random effects we reported the intraclass correlation coefficient and a generalized R 2 , calculated as the squared correlation between the fitted values of the model and the observed values of the data (Zheng and Agresti 2000). The former measures the correlation between observations from the same individual and can be interpreted as a measure of consistency of the results, and the latter provides information about the amount of variation in the data explained by the random effect (i.e., between-individual variation; Campioni et al 2013, Ló pez-Ló pez et al in press). Computations were run with the ''nlme'' extension for R (Pinheiro et al 2013).…”

“…The following spatial parameters were calculated: (1) average distance of all locations to natal nest or release point, recorded for each 15-d period; (2) size of the area explored, calculated using 100% Minimum Convex Polygon (MCP), 95% fixed kernel and 50% fixed kernel home ranges; (3) cumulative size of the explored area; (4) distance between the centroids of consecutive MCPs; (5) increase in size of the explored area (i.e., difference in the size of areas used consecutively); (6) overlap between consecutive MCPs; (7) distance between two consecutive roosting places (i.e., places where birds stay overnight, obtained from the first and last locations of each day); and (8) distance covered in 2 hr (only for birds equipped with ARGOS/GPS PTTs). Different levels of space use were assessed by means of the MCP, 95% kernel and 50% kernel, which represent a common standard approach in spatial ecology studies (Worton 1989, García-Ripollés et al 2011, Cumming and Cornélis 2012, Campioni et al 2013, Ló pez-Ló pez et al in press). The Least Squares Cross Validation method was used to calculate the smoothing parameter (Silverman 1986).…”

Spatial ecology and habitat use of adult Booted Eagles (Aquila pennata) during the breeding season: implications for conservation

“…Following similar studies focused on the analysis of spatio-temporal variations in home range behaviour of long-lived territorial raptors (e.g., Campioni et al 2013;López-López et al 2014a), we divided each breeding season into three periods: (1) a ''pre-laying'' period, which spanned from the arrival at breeding areas until egg laying; 2) a ''incubation ? nestling'' period, which comprised an average period of 39 days of incubation (García-Dios 2009) plus the period in which nestlings remained in the nest just before their first flights [52 days on average; García-Dios (2009)]; and finally, a (3) ''pre-migration'' period, including the dependence period of juveniles once fledged until the onset of autumn migration to their wintering grounds.…”