Differential Range Use between Age Classes of Southern African Bearded Vultures Gypaetus barbatus

Abstract

Bearded Vulture Gypaetus barbatus movements were investigated in southern Africa to determine whether an individual's age, sex or breeding status influenced its ranging behaviour and to provide the information required to guide conservation activities. Data from satellite transmitters fitted to 18 individuals of four age classes were used to determine range size and use. Because of the nature of the movements of marked individuals, these data could be used to determine the overall foraging range of the entire population, which was estimated to be 51 767 km2. Although juvenile, immature and sub-adult birds used different parts of the overall range, their combined foraging range was 65% (33 636 km2) of the overall range. Average adult home ranges (286 km2) were only around 1% the size of the average foraging ranges of non-adults (10 540 –25 985 km2), with those of breeding adults being even smaller (95 km2). Home ranges of breeding adults did not vary in size between seasons but adults utilized their home range more intensively whilst breeding, moving greater distances during the incubation and chick hatching period. Range size and use increased as non-adults aged. Immatures and sub-adults had larger range sizes during winter, but range use of non-adults did not vary seasonally. Range size and use did not differ between the sexes in any of the age classes. Information on home range size and use enables specific areas within the species' range to be targeted for management planning, education and conservation action.

Spatial and temporal movements in Pyrenean bearded vultures (Gypaetus barbatus): Integrating movement ecology into conservation practice

“…In a previous study25 based on nine pre-adult individuals in the Pyrenees tracked with satellite telemetry (but not GPS technology), the MCP obtained ranges of 945–19 691 km 2 . A similar pattern26 was observed in the subspecies Gypaetus barbatus meridionalis in South Africa in which breeding individuals covered on average 95 ± 19 km 2 , whilst non-territorial individuals covered areas of 10 540–25 985 km 2 . The differences are also significant in MCP, with 940.8 ± 1524.4 km 2 for breeding individuals and 1566–13 270 km 2 for non-breeding individuals.…”

“…This package was run in Rstudio 0.99 and R version 3.0.363 in combination with ArcGIS 9.1 (ESRI 2003) to build UD surfaces. Annual and seasonal UDs were estimated per bird using the ad hoc method as a smoothing parameter for comparison with previous studies26. Resolution of UD surfaces was established at 1 ha.…”

“…To date, information on the ranging behaviour of bearded vultures in the Pyrenees is limited to nine non-breeding individuals tracked using ARGOS satellite telemetry, which yielded 427 locations25, and a further nine non-breeding individuals monitored with GPS satellite telemetry17. Another study has been carried out on the subspecies Gypaetus barbatus meridionalis in South Africa, in which 18 individuals were monitored26. The current study aims to provide the first comprehensive understanding of the ranging behaviour of this vulture’s threatened Pyrenean population via the use of a larger sample size of all age-classes, tracked over a number of years/seasons with highly accurate GPS satellite technology.…”

Anthropogenic activities influence the abandonment of Bearded Vulture (Gypaetus barbatus) territories in southern Africa

“…Around each nest site we created a buffer with a 10 km radius (314 km 2 ; Figure 2). These circles were based on the average 90% kernel density home range estimates for adults (286 km 2 , 9.5 km radius; Krüger et al 2015) and aimed to encapsulate the overall home range of a territorial pair, which was supported by the circles encompassing 92% (86-96%, n ¼ 6) of all GPS fixes…”

Spatial and temporal movement of the Bearded Vulture using GPS telemetry in the Himalayas of Nepal

“…A detailed understanding of a species' movement ecology and behaviour in relation to biological and environmental factors is necessary to design and establish appropriate conservation management strategies (Morrison & Wood ). Although movement studies of the Bearded Vulture span more than three decades, they are limited to only a few mountain ranges in Europe and South Africa (Gavashelishvili & McGrady , Urios et al , Margalida et al , , Gil et al , Krüger et al , Reid et al ). Information on the movement ecology of vultures in the high‐elevation ranges of Asia is largely lacking (Alarcón & Lambertucci ).…”