Filetype
Robins captured as passage migrants by the Baltic Sea in Sweden at Falsterbo and Ottenby Bird Observatories, respectively, differ with respect to body mass, fat load and orientation behaviour. Relatively more birds with large visual fat deposits are captured at Ottenby than at Falsterbo, but robins at Falsterbo carry more fat than robins at Ottenby. Robins with small fat loads at Ottenby probably
The possibility that albatrosses use a geomagnetic bi-coordinate map for long-distance navigation at sea was investigated by evaluating how five different geomagnetic parameters (i.e. total field intensity, horizontal and vertical field intensity, inclination and declination) vary in areas where foraging albatrosses have been recorded by satellite telemetry in the Southern Ocean. Our objective was
The Eleonora's Falcon Falco eleonorae breeds on islands and islets in the Mediterranean region and feeds its young on migratory birds caught in the air. The breeding season is scheduled to coincide with the peak of bird migration. Between 12 and 20 September 1997 we measured flight tracks of falcons within a range of 4 km from their breeding cliffs on Isola di San Pietro 6 km off the south-west co
The moult of Barred Warblers Sylvia nisoria was studied during three winter seasons in southeastern Kenya at a southward passage site (Ngulia) and a wintering site (Mtito Andei). Most Barred Warblers migrating through Ngulia in November had yet to commence winter moult. These birds probably moulted subsequently in winter in northern Tanzania. In December, birds were found in heavy moult at Mtito A
The orientation of juvenile marsh warblers during autumn migration was investigated at two widely different latitudes, in Sweden and in Kenya, by cage experiments in manipulated magnetic fields during the twilight period after sunset. The objective was to compare responses by birds exposed to different geomagnetic conditions, particularly to the shift in magnetic inclination between the northern a
A male common swift Apus apus was equipped with a light logger on August 5, 2010, and again captured in his nest 298 days later. The data stored in the light logger enables analysis of the fascinating travel it made in this time period. The state of the art algorithm for geolocation based on light loggers consists in computing first sunrise and sunset from the logged data, which are then converted
Extensive ringing data from a coastal site (Falsterbo Bird Observatory) in southwesternmost Sweden were used to investigate the occurrence of reverse autumn migration among 20 passerine bird species oF widely different migration categories. The data demonstrate that reverse migration is a widespread and regular phenomenon among nocturnal as well as diurnal migrants and among irruptive migrants, te
The aim of this study was, by analysing recoveries and resightings of Caspian Terns Hydroprogne caspia ringed in Sweden, (1) to identify areas of importance during their migration and wintering, (2) to investigate the annual routines of migration and wintering of different age categories, and (3) to investigate how human activities, especially shooting, have affected survival of Caspian Terns over
Migratory naive birds are thought to find the migration route from their natal site to a specific wintering area by either clock-and-compass orientation or goal area navigation. These two alternative hypotheses were tested by extensive longitudinal displacements of juvenile wheatears, hatched in northeastern Siberia, on their first autumn migration towards the wintering area in East Africa. Orient
Sleep is a universal and complex state and it is widely agreed that this state is present in every animal species. However, the evolutionary origins of sleep remain ignored or misunderstood, which has led researchers to study, in various species, this common behaviour of all living organisms. Sleep is commonly studied at various levels under laboratory conditions, using tethered devices which reco
Brent geese, Branta bernicia hrota, were equipped with satellite transmitters on a spring stop-over site in Iceland. The brent geese deposit heavy fuel reserves for long-distance flights across the high Greenland ice-cap to breeding destinations in north Canada. Satellite tracking of brent geese on this journey serves the twofold purpose of testing specific predictions about: (i) size-dependent po
Stopover duration and fat accumulation were studied during autumn migration at two sites near Ottenby, Oland, SE Sweden in 1985 and 1986. Post juvenile moult was scored on juvenile birds. In several of the species fat class and body mass increased with day of season (thrush nightingale Luscinia luscinia, barred warbler Sylvia nisoria, and whitethroat S. communis), while in the lesser whitethroat S
In many migratory birds, males precede females during migration and arrival at the breeding sites. Three proximate mechanisms are proposed to explain this phenomenon of protandry: males 1) winter closer to breeding sites, 2) start spring migration earlier, and/or 3) migrate faster than females. So far, the relative contribution of these mechanisms to protandry is unknown. The present study investi
Brent Geese migrating in spring towards Arctic Canada have been tracked by satellite from Iceland to the Davis Strait. Length and direction of the stages were adapted to the geographic features and hospitability of the areas crossed; the ice-cap of Greenland was overflown in its southern part.
The orientation of four species of passerine long-distance migrants was studied in spring and autumn by orientation cage experiments during the twilight period after sunset in Sweden. Two groups of migrants from the Palaearctic-African migration system were used: migrants wintering mainly north of the magnetic equator in west Africa (pied flycatcher, Ficedula hypoleuca, and redstart, Phoenicurus p
Background: The motivation of birds to proceed with migration is associated with both endogenous and exogenous factors. According to their migratory situation and to the characteristics of stopover sites, birds might exhibit migratory motivation differently among sites. Although migratory motivation of migrating birds has been well stud-ied in many species, the investigation of the same species in
Ringing recoveries from 18 different passerine species captured at an inland ringing site in south Sweden (Kvismare Bird Observatory) were analysed with respect to direction and distance of migration in order to investigate the occurrence of temporary reverse movements opposite to the expected forward migratory direction towards south and south-west in autumn. The data demonstrate that movements i
The biometrics, age ratio and timing of migration of Robins were compared during autumn migration at an inland and a coastal site 200 km apart. The proportion of adult birds was higher at the inland site. The time of peak of migration differed between the two sites by 9 days. The daily distribution showed that at the coastal site the birds made a land‐fall at dawn, while at the inland site the mig
A migratory divide is a narrow region in which two populations showing different migratory directions meet and presumably also mate and hybridize. Banding of willow warblers, Phylloscopus trochilus, in Europe has demonstrated a migratory divide latitudinally across central Scandinavia. In autumn, southern birds migrate southwest to tropical West Africa, whereas northern birds migrate southeast to
