| 1. |
- Iwajomo, Soladoye B., et al.
(författare)
-
Autumn phenology and morphometrics in the Garden Warbler Sylvia borin at the Ottenby Bird Observatory, Sweden
- 2012
-
Ingår i: Ornis Fennica. - 0030-5685. ; 89:4, s. 233-240
-
Tidskriftsartikel (refereegranskat)abstract
- Trapping and ringing near ecological barriers can provide useful information about the migration strategies of bird species. In this paper we analyzed ringing data of the Garden Warbler, collected within the period of 1950-2008 at the Ottenby Bird Observatory, south-eastern Sweden, and describe patterns in migration phenology, morphometrics and fuel load. A total of 4,351 individuals aged as either adults or juveniles were ringed during the period (yearly averages 7.3 adults and 83.1 juveniles) in addition to 1,514 birds of unknown age. Both age-specific and combined yearly totals did not significantly vary over the years. Median passage dates were 24 August, 30 August and 2 September for adults, juveniles and birds of unknown age, respectively. Median passage did not change significantly over the years. Among adults, larger individuals passed the observatory earlier than smaller individuals. The average fuel load was estimated at 24.3% of Lean Body Mass (LBM), and late-migrating individuals had higher fuel deposits than early migrants. Maximum fuel load was estimated at 82.5% of LBM; such an individual may be capable of a direct flight from Ottenby region to the Mediterranean area.
|
|
| 2. |
- Iwajomo, Soladoye B., et al.
(författare)
-
Intra-African movements of the African cuckoo Cuculus gularis as revealed by satellite telemetry
- 2018
-
Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857. ; 49:1
-
Tidskriftsartikel (refereegranskat)abstract
- Despite many bird species migrating regularly within the African continent, in response to rainfall and breeding opportunities, documented evidence of the spatiotemporal patterns of such movements is scarce. We use satellite telemetry to document the year round movement of an intra-African migrant breeding in the savannah zone of sub-Saharan Africa, the African cuckoo. After breeding in central Nigeria, the birds migrated to more forested sites in the Adamawa region of Cameroon (n = 2) and western Central African Republic (n = 1). Departure from the breeding ground coincided with deteriorating environmental conditions whereas arrival at the non-breeding sites matched period of increasing vegetation greenness. Migratory movements generally occurred during dark hours. In total, an average distance of 748 km in 66 d was covered during the post-breeding migration and 744 km in 27 d during return journey with considerable individual variation and with more stopover sites used during post-breeding migration. The diversity of migration routes followed suggests a relatively variable or flexible initial migration strategy, high individual route consistency as well as high fidelity for non-breeding grounds.
|
|
| 3. |
- Iwajomo, Soladoye B., et al.
(författare)
-
Seasonal movements of Black Coucals Centropus grillii in Nigeria
-
Ingår i: Ostrich. - 0030-6525. ; , s. 1-6
-
Tidskriftsartikel (refereegranskat)abstract
- The scale of movement associated with the migration of many intra-African bird species is still poorly known even with the increasing availability of tracking devices. In this study, we tracked the movements of Black Coucals Centropus grillii breeding in Nigeria from late July using satellite telemetry. Individuals remained on the breeding site for several months; two individuals transmitted after October and these two moved shorter distances (< 100 km) away from the breeding site in early December. One of these was tracked for a full year, moving to a site 175 km south of the breeding site in early January and returning to the breeding site in late May. The bird migrated faster during the return journey (58 km day−1) as compared to the post-breeding journey (5.9 km day−1). The overall home range (90% kernel density) during breeding was 20.4 ± 3.3 km2 (mean ± s.d.) and the core (50%) 5.0 ± 1.6 km2 with no apparent clear change outside of the breeding season. Vegetation conditions at the distant site were apparently poorer although in an average year the move would have led to improved conditions. Short-distance seasonal migration of Black Coucals might be widespread in drier seasonal habitats.
|
|
