Ornis Hungarica. vol.2. (1992) p.17-24.
Study of spring migration by weather radar in Eastern Hungary
The main characteristics of spring migration were studied by meteorological radar in the Eastern part of the Carpathian Basin for 8 days in 1987. The radar is situated at Napkor, 200 km ENE from Budapest,,and it can detect the birds in a 25-100 km range. The echoes were displayed on PPI and were recorded on 35 mm film by time exposure. During the study 6546 bird echoes were recorded on 413 pictures. The intensity of bird echoes was high at sunrise and early afternoon. In 25 km range, the intensity of the echoes was high at sunset because of intensive migration of passerine birds. The average direction was northeast (42°), and its daily value varied between 33°-59° during the study. Thee changing of the direction might come from the change in the composition of migrating species. Above some areas, the bird echoes were concentrated, and these concentrations showed a close relationship to some topographical elements.