FUCHS P & J VAN DE LAAR (2008) Dispersal and settlement of young Little Owls Athene noctua. LIMOSA 81 (4): 129-138.
During 1972-1989 a population of Little Owls was studied
in the Central Betuwe, an area between the Lower
Rhine and Waal rivers in the province of Gelderland
measuring 100 km2 (Fig. 1). The study was initiated to estimate
the impact of changes in landscape (disappearance
of tree orchards) and agricultural practice on density
and reproduction of the species. This article focuses
on the dispersal and the chances of settlement of young
Little Owls in their natal area.
After three years of ringing nestlings and adults, 56-79%
of the trapped adultswas found to have been ringed earlier
(Tab. 1). Breeding adults mostly stayed in the same
breeding territory: only 6% of 352 retrapped birds
moved to a different territory in the course of the study.
The largest distance was covered by a female resettling
1600 m from her previous breeding site. Of the ringed
nestlings only 8% was recovered breeding within the
study area, most of them (65%) in their first year (Tab. 2).
Nestlings found breeding within the study area settled
on average at 2689 m from their place of birth; this must
be regarded as aminimumsince birdsmoving out of the
study area were less likely to be detected. Altogether the
results point out that young Little Owls are highly resident
and adults show high territory fidelity.
Males tended to stay closer to their natal nest (Fig. 2), and
were more often found breeding within the study area
than females (35% vs. 15%). Young born in the more
strongly degraded landscape of the western part of the
study area dispersed further than young from the more
intact eastern part, probably reflecting that birds in the
western part have to cover a larger distance tomeet suitable
breeding habitat. Recruitment rate of nestlings (as
breeding adult) fluctuated with winter severity. Of
young hatched in 1978 (followed by a severe winter with
36 days of snow cover), only 4% were found breeding in
later years, contrasting with 12-14% found in earlier and
slightly less than 10% in later years (Tab. 2). Young that
were born early in the season more often settled within
the study area (11%) than young born late (8%; Tab. 3).
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