Autumn and spring migration of the Reed Warbler Acrocephalus scirpaceus in Egypt - some interesting aspects and questions

摘要

Four ringing stations of the SE European Bird Migration Network in Egypt (at the coasts of the Mediterranean and Red seas, in the Nile Valley, and at the northern edge of the Sahara) provided data on birds resting in adequate habitats. At three stations more birds per day were caught in spring than in autumn. Deviating geographical conditions induced high capturing numbers at the Red Sea coast, particularly in autumn. Differences between spring and autumn may indicate loop migration and/or seasonallydiffering flight or resting strategies. Wing-length distribution may indicate passage of different populations through Egypt. In autumn, birds with low fat scores were caught in high proportion after the crossing of the Mediterranean Sea, while averagefat scores increased in birds approaching the edge of the Sahara.