A comparison of passerine migration in southern and northern Israel

In Israel, a well-known avian migratory bottleneck, there is a temporal and geophysical divide in the flyways. The migration at Eilat, at the southern tip of Israel, is disjunct from the flyway in central and northern Israel. In order to elucidate the differences between the two flyways, we compared the data collected simultaneously at the Kfar Ruppin ringing station in northern Israel, and in the IBRCE Bird Sanctuary in Eilat at the southern tip of Israel. We chose the three most common species that are typical long distance, trans-Saharan, passerine migrants: Blackcap (Sylvia atricapilla), Lesser Whitethroat (Sylvia curruca) and Reed Warbler (Acrocephalus scirpaceus). At both ringing stations, the number of migrants recorded in spring was considerably greater than in autumn for all three species. Individuals from all species analysed in both passage seasons at Kfar Ruppin had longer wings than in Eilat, and in spring all three species were heavier in Kfar Ruppin. Our study is the first to show that there are biometric differences within Israel and stress the need to study the eastern migratory flyway of the Western Palaearctic in order to fully understand the intercontinental movements of the EurAsian migratory passerine populations.

► We studied differences in two bird migratory flyways that occur in Israel.
► We compared data from ringing station in northern and southern Israel.
► Birds in the north had longer wings in spring and autumn.
► In spring, birds were heavier in the north.