دراسة هجرة الطيور في وسط وشرق الأردن من النواحي التالية: ظواهر التكرار والتوقيت في الهجرة واستخدام الموائل، الفسيولوجية البيئية، التوجه

الكلية: كلية العلوم

الجهة البحثية: الجامعة الهاشمية

عنوان البحث المنشور: Seasonal variation in body fat and weight of migratory Sylvia Warblers in central Jordan

سنه النشر:  2004

ملخص البحث المنشور: The physical state of Sylvia Warblers stopping over in a large plantation on the edge of the eastern desert of Jordan was studied during spring and autumn migration. Sylvia species caught in autumn had generally higher fat loads than in spring, which can be attributed to common aspects of migration habits. However, variations in strategies of different species were indicated by different distributions of fat scores and physical changes during stopping over. In spring, Blackcaps stopping over replenished their fat reserves, possibly as preparation for crossing further desert areas in the Middle East. Several Lesser Whitethroats stopped over in spring without replenishing fat reserves. Thus their choice of a suitable site with low predation risk was probably to recover water balance and/or muscle tissue after crossing the Sahara. It is moreover assumed that Lesser Whitethroats are able to gradually cross open deserts of the Middle East where they may feed en route in spring. Many Garden Warblers stopped over without replenishing fat reserves but with a significant increase in body mass, which indicated recovery of water balance and/or muscle tissue. Garden Warblers were not recorded in open desert areas, thus they are believed to avoid further deserts and migrate gradually northwards along more fertile areas of the Middle East, where they feed en route. In autumn, most birds had high fat loads, but leaner Blackcaps and Lesser Whitethroats were frequent, some of which were found to stop over and replenish fat reserves, apparently in preparation for crossing the Sahara. Variations in migration patterns among closely related long distance migrants are especially evident after crossing the Sahara in spring, and might reflect different migration strategies.

رابط البحث المنشور: https://www.zobodat.at/pdf/Vogelwarte_42_2003_0191-0202.pdf