Analysis of Ring Recoveries of Song Thrushes Turdus philomelos in North Africa

Abstract

This study investigates the wintering range and migratory patterns of the Song Thrush in North Africa, focusing on the Maghreb region. Despite the fact that this is the southernmost limit of its wintering range, comprehensive analyses of its geographic origin and spatial distribution are lacking. The research utilizes 840 records, representing the first comprehensive analysis of ringed bird recoveries in North Africa. Findings reveal that the Song Thrush is a common visitor to the Mediterranean belt of North Africa, with distinct migratory routes for different populations. Notably, Italy contributes significantly to the total number of recoveries. The study highlights North Africa as a wintering area for both long-distance migrants and partially migratory populations from Western and Central Europe. An intriguing observation is the disproportionate concentration of recoveries in Algeria (89.6%), particularly in the Kabylie region, suggesting potential biases due to hunting and trapping activity. Temporal analyses indicate a decline in captured birds from the 1960s to the 2000s, possibly reflecting changes in hunting pressures across North Africa. The seasonal distribution of recaptures shows a peak in January, emphasizing the thrushes’ southward movements within their wintering range. The study challenges previous assumptions of early spring migration, suggesting onset in the second 10-day period of February. Contrary to previous claims, our data do not support prenuptial movements from Kabylie to Tunisia. Instead, sedentary behaviour in wintering areas until March is suggested by both geographical coordinates and recovery data. Satellite transmitter data confirm departure dates in March for thrushes marked in December in Italy. In summary, this study provides a concise overview of Song Thrush wintering dynamics in North Africa, offering insights into diverse migratory patterns and regional biases and challenging previously held assumptions about prenuptial movements and migration onset.