Talking Naturally

Species Note

Barn Swallow roosts at Ebbaken, Nigeria

European Barn Swallows winter in West Africa in enormous roosts, and ringing at Ebbaken connects them to breeding populations far to the north.

A Barn Swallow perched on a wire against a clear blue sky, dark glossy blue above, with a red throat and long outer tail streamers.
Barn Swallow on the wire. Photo Donald Davesne · source · CC-BY

Barn Swallows Hirundo rustica that breed across Europe winter in sub-Saharan Africa, and in West Africa they gather in roosts of extraordinary size, hundreds of thousands of birds coming into reedbeds or plantations at dusk.

Work at Ebbaken, in the Boje area of Cross River State in south-eastern Nigeria, has involved ringing birds at such a roost, and Pierfrancesco Micheloni has been among those involved.

The value of ringing at a wintering roost is specific. A swallow ringed on a British or Italian nest tells you where that bird bred. Recovering it in Nigeria establishes where it went, and, in aggregate, which breeding populations use which wintering areas. That connection is what makes it possible to say whether a decline observed in a European breeding population is happening on the breeding grounds, on migration, or in Africa.

Without it, a national breeding survey can document a decline and cannot locate its cause. Ringing at both ends of a migration is the only method that links the two, and roosts of this size are where the African end of the work is practical.

It also depends on local capacity: a roost in Cross River State is monitored by people who live near it, not by visiting expeditions, and the continuity of the dataset follows from that.