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SITE DESCRIPTION
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Öland is
an island off the coast of Sweden in the Baltic Sea.
One of the best places to study stopover ecology in
Europe is on this east coast island, where the well-known
Ottenby Bird Observatory is located. The station's "trapping
gardens" are manicured gardens with low deciduous
and evergreen shrubs and few trees interrupted by buildings
and surrounded by low marsh and lawn.
Ventotene is a
Mediterranean island off the coast of Italy. Many Palearctic-African
migrants fly across the Saharan Desert and the Mediterranean
Sea, sometimes in a nonstop 40-hour flight. Not surprisingly,
landbird migrants deposit enormous fat stores (40-50%
of their body mass) to fuel the journey. In spring,
many migrant landbirds stopover on Italian islands,
including Ventotene, to rest and refuel. The island
is a hilly, volcanic formation with steep cliffs, primarily
covered by cultivated or fallow lands with few trees.
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RESEARCH ACTIVITY
We collected data
on passage of Pied Flycathcers and Spotted Flycatchers
in collaboration with the Ottenby
Bird Observatory (Öland) and
researchers and volunteers from the Istituto Nazionale
per la Fauna Selvatica in Bologne, Italy
(Ventotene) during the springs of 1996 and 1997. These
are two latitudinally separated western European sites
representing the migratory progression from wintering
to breeding. Migrants
were captured in 36 mist-nets (Ventotene) and Helgoland
traps (Öland)
during their northward migration.
We also performed
aviary experiments on intraspecific competition of flycatchers
during spring passage at the Ottenby Bird Observatory
in 1997.
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SARAH MABEY
Intersexual
competition and differential costs of reproduction for
the sexes may influence observed migratory patterns and stopover
ecology. Sarah tested these two hypotheses regarding differential
spring migration and ecological segregation of the sexes during
migratory stopover for two
Palearctic-African migrants, the dimorphic Pied Flycatcher
(Ficedula hypoleuca) and the monomorphic Spotted Flycatcher
(Muscicapa striata ). As
part of her dissertation work, Sarah employed two experimental
approaches to determine the underlying causes of differential
migration and sexual segregation: field manipulations of food
resources, and aviary competition experiments.
Sarah
found that male flycatchers migrated significantly earlier
than females, with peak passage for the sexes separated by
as much as 10 days. Male flycatchers were also socially dominant
to females in the aviary experiments. Female flycatchers had
greater access to food when competing with other females rather
than males. Sarah suggests that early migrating females may
experience disadvantages in food acquisition relative to those
later-migrating females.

The
University of Southern Mississippi. Last modified:
24 February, 2007
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Questions and
Comments?
URL: http://www.usm.edu/mbrg/OlandVentotene.html
AA/EOE/ADAI
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