WASSINK G (2014) Dispersal of juvenile Eagle Owls Bubo bubo from the Netherlands. LIMOSA 87 (2): 91-98.

In 2008-2013 12 young Eagle Owls from the Netherlands were tracked using battery-powered gps-satellite transmitters and solar-powered gps-gsm loggers. Tracking devices were programmed to determine one gps position once every night and, for the devices used in 2011 and 2013, also one during the day. On average, the owls left their natal territories on 18 September when 173 days old. Tracks during the dispersal phase were surprisingly straight, with movements predominantly in northwestern, northeastern and southeastern directions (Figs. 1 & 3). Owls travelled on average 8 km per night (excluding stopovers), and at most 70 km (Tab. 2). Already in the first two weeks of their dispersal the Eagle Owls reached the maximum distance from the nest (68 km). After about three weeks 'late autumn sites' were reached, on average at 53 km from the nest (Tab. 1). The owls remained here for on average 78 days, until the end of December, and arrived at their final breeding (?) territories in spring. Final territories were located in Germany, Belgium, the Netherlands and France, indicating a frequent exchange between different European subpopulations. During the dispersal phase, Eagle Owls regularly travelled through half-open to open landscapes and also regularly visited farms and urban areas. Late autumn sites were characterized by steep hills or high structures like garbage dumps and push moraine. Here the owls usually did not roost in the same tree but regularly switched between day roosts. Coniferous trees were often used as day roosts, especially during winter.

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