Encountering wild birds

Dawn on the Seine estuary, late August. We arrive at the edge of the reedbed, packed into two cars, squashed together into a collective excitement that mingles under the roof in soft breath. We are anxious to walk off the four o’clock bleariness: to inhale the brightening air and cast fresh shadows on damp plants. Looking back down the road along which we have travelled – at the way the tarmac winds back on itself again and again – it is hard not to wonder how, at some distant point, the road itself does not forget the place it set out to reach in the first place.

We are here in the marshlands of Normandy — Emma, Dan and a team of other French and English bird ringers — to catch and ring endangered aquatic warblers (Acrocephalus paludicola) as they migrate from their breeding territories in Eastern Europe and Western Asia to their wintering grounds in West Africa. The CRBPO (Centre for Research on the Biology of Bird Populations) runs a project that monitors the numbers of migrating warblers in this region of France. As is common practice in ornithological research, the birds’ legs are fitted with metal rings that are stamped with unique identification sequences. This means that post-ringing, each bird is identifiable as an individual.

We work from first light to mid-morning; sometimes we catch over a hundred birds in a day; often not a single one of these is an aquatic. On such days it feels as if the birds are lost: flying in strange directions, overshooting us in the dark. Vanished to somewhere else.

The timing of this year’s fieldwork is significant: the results of Emma’s PhD research have just been published. They showed that the extinction of threatened bird species will disproportionately affect those species with the most unique morphological traits, and thus the diversity of traits across the whole avian phylogeny will shrink at a faster rate than previously expected. It is a critical discovery. Those species that tend to have the most diverse traits (and thus also provide the most unique ecosystem services) will likely go extinct first. Since the widest range of animal morphologies (and therefore ecosystem functions) is linked to an ecosystem’s resilience to environmental change, Emma’s results speak of a dramatic degradation of ecosystems’ stability at the global scale. Wading through the Seine’s tidal swell as we approach our first moments of contact with wild birds, it is impossible not to internalise this larger reality of environmental crisis.