Home Range and Excursive Post-Breeding Movements of Eurasian Eagle-Owls Revealed by GPS Satellite Transmitters

Abstract

Investigating space use of wild birds provides important knowledge of bird behavior and ecology, which is crucial in the management and conservation of threatened species. In the present study, we used GPS satellite telemetry to investigate space use and movements of seven adult Eurasian Eagle-Owls (Bubo bubo) in Norway during breeding and post-breeding seasons. Breeding adults had a mean home range size of 42.9 km 2 (SD 6 35.1 km 2 ; 95% kernel density estimation H ad hoc ), and five individuals performed long (.20 km) excursive movements away from their breeding territories during autumn. Such wide-ranging behavior has not previously been reported for adults of the nominate subspecies B. b. bubo. The study demonstrates the need to investigate seasonal movements of species, populations, and age groups even if they are considered residents, and provides valuable information for management and conservation of the Eurasian Eagle-Owl.

Striking Variability in the Post-Reproductive Movements of Spanish Red Kites (Milvus milvus): Three Strategies, Sex Differences, and Changes over Time

“…They were also clearly distinguishable from the sedentary because they performed clear displacements from the nest of a considerable distance. These movements have a component more exploratory and dispersive, as is shown in previous works [ 14 , 15 , 16 , 17 ], similarly to the dispersal movements of immature birds (<2 years old).…”

“…These birds make long movements from their breeding areas, without marked seasonality or direction, followed by a return journey. This type of post-reproductive movement has been previously identified, under various terms, in some typically sedentary raptors such as the golden eagle ( Aquila chrysaetos ) [ 14 ], the bald eagle ( Haliaeetus leucocephalus ) [ 15 ], the eagle owl ( Bubo bubo ) [ 16 ], or the burrowing owl ( Athene cunicularia ) [ 17 ]. These species leave their reproductive territories after breeding to explore areas far away from them.…”

Migración y ecología espacial del milano real en España

“…También son claramente distinguibles de los sedentarios "puros" porque sí se observan claros desplazamientos respecto al nido de una amplitud latitudinal considerable. Son movimientos de carácter más exploratorio y dispersivo, similares a los que se observaron en la bibliografía consultada (Rosier et al, 2006;Moss et al, 2014;Wheat et al, 2017;Heggøy et al, 2021) o los que realizan los juveniles de rapaces.…”

“…Este tipo de movimientos posreproductivos exploratorios han sido identificados con anterioridad en algunas rapaces sedentarias como el águila real (Aquila chrysaetos) (Moss et al, 2014), el águila calva (Haliaeetus leucocephalus; Wheat et al, 2017), el búho real (Bubo bubo; Heggøy et al, 2021) o el búho excavador (Athene cunicularia) (Rosier et al, 2006), que abandonan el área de cría tras la reproducción para explorar zonas muy alejadas de la misma. También se han observado en rapaces típicamente migradoras como el aguilucho lagunero occidental (Circus aeruginosus), que realiza estos movimientos en los periodos pre y post migratorios (Strandbergn et al, 2008).…”

“…Esta especie es muy adaptable y ocupa un amplio rango de distribución, desde regiones casi árticas hasta el desierto del Sáhara (Cramps y Simmons, 1979). De igual manera, en esta y otras especies como el búho real (Bubo bubo) (Heggøy et al, 2021) o el águila calva (Haliaeetus leucocephalus) (Wheat et al, 2017) se observa cómo existe una marcada diferenciación intraespecífica en las estrategias posreproductivas de sus individuos.…”