SEEN - SE European Bird Migration Network
Results of the orientation tests in spring and autumn in different experimental conditions
Dimitar Ragyov
Vrazdebna, str. 3 N17, Sofia, Bulgaria

During 2003 year two temporary ringing stations were operated in Bulgaria. Orientation experiments with Busse cages were made. 217 significant experiments were obtained at ringing station “Sakar” (Spring season). The most numerous tested species were Sylvia atricapilla (n=71), Lanius collurio, (n=33) Luscinia luscinia (n=27) and Luscinia megarhynchos (n=17). Two main directions were demonstrated – NNE and W.  538 significant experiments were obtained at ringing station “Dragoman” (Autumn season). The most numerous tested species were Acrocephalus schoenobaenus (n=154), Acrocephalus scirpaceus (n=151), Acrocephalus arundinaceus (n=55), Phylloscopus trochilus (n=51), Locustella luscinioides (n=49) and Acrocephalus palustris (n=18). The main demonstrated direction was SSW. According the above results some problems are discussed: 1. Influence of the researcher and how it reflects on the demonstrated directions; 2. Opportunities for excluding human influence using special made platform (it doesn’t allow birds to see the researcher when he puts them in the cages). Results obtained before and after using this platform are compared and discussed. More westward azimuths of autumn migration became noticeable in the second case.
Created by Pronetix 2006