Ornis Hungarica. vol.8 Suppl. 1.. (1998) p.137-144.
Migration of the Garden Warbler (Sylvia borin)
Our studies were conducted at the Ã“csa Bird Ringing Station (47°15'N, 19°15'E) between 1983 and 1994. During this period, 2356 Garden Warblers were ringed and 686 of these were recaptured. I Spring migration of Garden Warblers started in the last decade of April and lasted until the last days of May. In the study area, breeding started during the second part of this period. Autumn migration started at the end of the first decade of August, little before the end of partial moulting. The last birds left the area at the end of September. Adult and young birds migrated at the same time, with a similar pattern. Migration was very rapid, in the intensive periods only 12.5-13. 1 % of the young and 3.5-4.9% of the adult birds were recaptured in the days following the first capture. The mean length of stay was short in both age groups, averaging 2.6-4 days. In the most intensive period of autumn migration body weight of captured birds was 8- 10% higher in average than in the preceding dispersal period. Body mass of recaptured, resting birds started to increase in the second third ofthe migration period, although only to a small degree. Accumulated body fat of captured birds was only 10- 1 2% even in the most intensive period of migration. Based on recaptures, Garden Warblers migrating through the Carpathian basin continued towards the Apennine Peninsula. According to our estimates (using Tucker's method, Tucker 1974 in Bairlein 1992) accumulated body fat was sufficient to fuel migration to North Africa in 30% of the birds. The majority had to increase their body mass during the further southward journey.