Prothonotary Warbler by Michelle Davis

Ottenby lighthouse


 

SITE DESCRIPTION

Öland, Sweden

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.


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.

Aviary cup with worms

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.

Sarah Mabey with Pied Flycatcher

 

 

The University of Southern Mississippi. Last modified: 24 February, 2007 . Questions and Comments?
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