In most birds the dispersal process is usually initiated with a straight emigration from the natal site and the cessation of parental care. Yet for some species, particularly those with extended periods of parental care (such as many large raptors like golden eagles), individuals can carry out prospecting movements prior to dispersing. Prospecting behaviour probably involves individuals searching and evaluating sites, and may influence further decisions made at later stages of the dispersal process. I used long life GPS satellite transmitters fitted to nestling golden eagles to follow them as they dispersed. Young golden eagles emigrated from their natal home ranges from 44 days until 250 days after fledging. The rate at which individuals emigrated increased over time and individuals that developed motility more rapidly also emigrating earlier. Over 90% of individuals made at least one distinct movement away from the natal home range prior to emigrating, with early departing individuals making fewer prospecting trips prior to a definitive departure. Individuals that prospected undertook up to 11 prospecting loops that lasted up to 10 days and with longer duration trips being longer in overall length and maximum distance explored from the natal home range. The direction of prospecting forays was positively correlated with the direction of eventual departure, but the penultimate exploration was no more correlated than less recent explorations indicating a non-random exploration direction. These movements during transience were focussed on a series of temporary settlement areas (TSAs) that varied in number per individual and re-visitation rate. TSAs were used more often during the summer months and locations outside of TSAs occurred much more frequently in the core of known breeding home ranges.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:633275 |
| Date | January 2014 |
| Creators | Weston, Ewan |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=215233 |
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