This small warbler has a pale head and underparts. It breeds around the western Mediterranean and winters south of the Sahara.
Its bill is slender and its legs are black. Greenish wings, back and outer tail contrast with the whitish head and underparts.
Spring migration was studied at two ringing stations about 3,820 kilometres apart: Gibraltar at the western end of the Mediterranean and Eilat in southern Israel. Researchers compared Western Bonelli’s Warblers at Gibraltar with Eastern Bonelli’s Warblers at Eilat, recording their passage dates and body measurements during the same period.
The mean passage date for Western Bonelli’s Warblers at Gibraltar was 15 days later than the date recorded for Eastern Bonelli’s Warblers at Eilat. Western birds had shorter wings, while birds measured at Eilat were in poorer body condition than those at Gibraltar. The two distant stations recorded contrasting spring passage patterns at opposite ends of the Mediterranean.
An extinction-risk assessment has not been added yet.
Western Bonelli’s Warblers pass Gibraltar on routes towards West Africa, while Eastern Bonelli’s Warblers pass Eilat on routes towards East Africa. The two ringing stations recorded passage timing and body condition at the western and eastern ends of the Mediterranean.