Dispersal and survival of Aquila fasciata (Bonelli's Eagle) differ across arid, semi-arid, and Mediterranean natal habitats

Mayrose, Asaf , Hatzofe, Ohad , Troupin, David , Sapir, Nir

2026-01-01 ORNITHOLOGY 2026   143(卷), 1(期), (16-16页)

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Dispersal is an important ecological process influencing population viability, demography, and gene flow. For non-migratory raptors like the Aquila fasciata (Bonelli's Eagle), natal dispersal-the movement between the birthplace and the first breeding site-is a critical life stage. However, the role of natal habitat on the dispersal process and its implications for population viability and conservation remains poorly understood. This study examined how natal habitat across three distinct biogeographic regions influences dispersal movement, habitat use and survival of juvenile A. fasciata in the Levant (within areas administered by Israel and the Palestinian authority). Using global positioning system (GPS) telemetry, 55 juvenile eagles originating from Mediterranean, semi-desert, and desert habitats were tracked over their dispersal journeys. Key aspects such as dispersal direction, distance, temporary settlement areas (TSAs), territorial recruitment and mortality were analyzed in relation to the natal climatic conditions. Results revealed clear habitat-based differences in dispersal patterns. Desert-hatched eagles dispersed the farthest, with some crossing the Sahara and Arabian deserts to reach sub-Saharan Africa or southern Arabia, while Mediterranean and semi-desert eagles remained more localized. Water bodies acted as barriers, shaping dispersal routes and TSA distribution. Throughout dispersal, eagles occupied areas with precipitation levels similar to their natal sites, supporting natal habitat preference induction (NHPI) hypothesis. Recruitment data further indicated strong fidelity to natal climatic zones, with only 1 out of 11 eagles settling outside its natal zone. Mortality patterns varied by habitat types, with desert-hatched eagles experiencing the highest proportion of deaths outside the study area. These findings underscore the influence of natal habitat on dispersal, highlighting how local environmental conditions shape movement patterns, species distributions, and population trajectories. Understanding these patterns is crucial for raptor conservation, particularly in managing habitat-specific risks and transboundary movements. We studied how young Aquila fasciata (Bonelli's Eagle) move from their hatch places until they mature and settle to breed, over a period of 2-4 years. Using global positioning system (GPS) tracking, we followed 55 eagles from 3 habitat types-Mediterranean, semi-desert, and desert-to examine their movement and settlement patterns. Eagles hatched in desert areas traveled much farther and more directly south, often crossing vast deserts like the Sahara and Arabian. Eagles typically settled in habitats resembling their hatch place, suggesting early-life habitat imprinting that influences their long-term behavior. These movement strategies affected survival and breeding recruitment, with notable differences in where and how eagles from different habitats died. This research provides valuable insights for more effective conservation of endangered A. fasciata in harsh and fragmented landscapes, suggesting that conservation efforts need to additionally focus on conserving key movement corridors and settlement areas. La dispersi & oacute;n es un proceso ecol & oacute;gico importante que influye en la viabilidad poblacional, la demograf & iacute;a y el flujo g & eacute;nico. Para rapaces no migratorias como Aquila fasciata, la dispersi & oacute;n natal-el movimiento entre el lugar de nacimiento y el primer sitio de reproducci & oacute;n-es una etapa cr & iacute;tica de la vida. Sin embargo, el rol del h & aacute;bitat natal en el proceso de dispersi & oacute;n y sus implicaciones para la viabilidad poblacional y la conservaci & oacute;n sigue siendo poco comprendido. Este estudio examin & oacute; c & oacute;mo el h & aacute;bitat natal en tres regiones biogeogr & aacute;ficas distintas influye en el movimiento de dispersi & oacute;n, el uso de h & aacute;bitat y la supervivencia de juveniles de A. fasciata en el Levante (dentro de las & aacute;reas administradas por Israel y la Autoridad Palestina). Mediante telemetr & iacute;a GPS, se rastrearon 55 & aacute;guilas juveniles originarias de h & aacute;bitats mediterr & aacute;neos, semides & eacute;rticos y des & eacute;rticos a lo largo de sus trayectorias de dispersi & oacute;n. Aspectos clave como la direcci & oacute;n y distancia de dispersi & oacute;n, las & aacute;reas de asentamiento temporal (AAT), el reclutamiento territorial y la mortalidad fueron analizados en relaci & oacute;n con las condiciones clim & aacute;ticas natales. Los resultados revelaron claras diferencias en los patrones de dispersi & oacute;n seg & uacute;n el h & aacute;bitat. Las & aacute;guilas nacidas en el desierto se dispersaron m & aacute;s lejos, con algunas cruzando los desiertos del Sahara y de Arabia para llegar al & Aacute;frica subsahariana o al sur de Arabia, mientras que las & aacute;guilas mediterr & aacute;neas y semides & eacute;rticas permanecieron m & aacute;s localizadas. Los cuerpos de agua actuaron como barreras, moldeando las rutas de dispersi & oacute;n y la distribuci & oacute;n de las AAT. Durante la dispersi & oacute;n, las & aacute;guilas ocuparon & aacute;reas con niveles de precipitaci & oacute;n similares a sus sitios natales, lo que respalda la hip & oacute;tesis de inducci & oacute;n de preferencia por el h & aacute;bitat natal. Los datos de reclutamiento indicaron adem & aacute;s una fuerte fidelidad a las zonas clim & aacute;ticas natales, con solo 1 de 11 & aacute;guilas asent & aacute;ndose fuera de su zona natal. Los patrones de mortalidad variaron seg & uacute;n el tipo de h & aacute;bitat, con las & aacute;guilas nacidas en el desierto experimentando la mayor proporci & oacute;n de muertes fuera del & aacute;rea de estudio. Estos hallazgos subrayan la influencia del h & aacute;bitat natal en la dispersi & oacute;n, destacando c & oacute;mo las condiciones ambientales locales moldean los patrones de movimiento, las distribuciones de las especies y las trayectorias poblacionales. Comprender estos patrones es crucial para la conservaci & oacute;n de las rapaces, particularmente en la gesti & oacute;n de riesgos espec & iacute;ficos del h & aacute;bitat y de los movimientos transfronterizos.