As I approach the entrance to the A27 underpass, I slow my pace and peer into the gloom. Traffic rumbles overhead, drowning out the burbling Langbrook stream, which runs alongside the footpath. This dank, noisy, concrete cavern seems an unlikely place for a bird to choose to take up residence, but since the end of September it has become the favourite haunt of a grey wagtail.
Sure enough, I spot the wagtail bobbing and weaving in and out of the railings at the water’s edge, its ash-grey head and wings contrasting with a sulphur-yellow rump and underparts. Its pale buff-coloured throat and eye-stripes suggest that it is probably a juvenile bird.
While they are resident year-round, grey wagtails are a less common sight in Britain than their pied cousins. The species was added to the UK red list for birds in 2015 and scientists are still trying to determine the reason for their long-term decline. While some remain in their territories all year, most are altitudinal migrators, leaving their upland and northern breeding grounds in autumn and overwintering in the English lowlands, where they are joined by migrants from continental Europe.
They are colloquially known as “water wagtails”, owing to their strong association with fast-flowing freshwater streams, but at this time of year their habitat expands to include canal towpaths, sewage works, coastal salt marshes, farmyards, gardens and urban rooftops.
During the past few weeks this individual has become increasingly confiding. When I pause just a few feet away from where it is feeding, it continues trotting down the path towards me, its long black and white tail pumping furiously, and head flicking from side to side as it sets its sights on a swarm of midges that is rising up to wreath my head.
A cyclist swooshes into the tunnel, ringing his bell. The wagtail takes flight, uttering a single metallic “tchik” call as it flits between the paddles of the replica water wheel that sits in the preserved remains of the old mill race. Settling midstream on a mossy boulder, it dances up to snatch a minute insect out of the air, its tail feathers splaying and wings snapping open like a pair of flamenco fans.
