Eleanor Whitcombe
The Bird Behind the Bubbling Song
If you have ever stood on a saltmarsh at dusk in late winter and heard a sound like someone blowing bubbles through a curved pipe, you have met the curlew. The Eurasian curlew is our largest wading bird, a mottled brown figure with a long, down-curved bill that looks almost too elegant for the mud it probes. It is also one of Britain's most rapidly declining breeding birds, which makes learning its calls and its haunts more than a pleasant hobby — it is a small act of noticing something we are in danger of losing.
Curlews slip between two worlds each year. From around March, they head inland to moorland, rough pasture and hay meadows to nest. Come July and August, they drift back to the coast, where estuaries, mudflats and damp grazing marshes carry them through autumn and winter. That means you have two entirely different listening seasons, and the calls change with them.
Where to Listen on the Coast
Estuaries are the heart of it. Anywhere a river slows and spreads — the muddy, half-salted ground between land and open sea — you have potential curlew country. Look for wide expanses of exposed mud at low tide, fringed by saltmarsh, with nearby fields that stay soft underfoot.
Practical places to try, in the broadest terms:
- Estuarine mudflats with a decent tidal range, where invertebrates are within reach of that long bill.
- Saltmarsh edges, especially where creeks and gullies cut through the vegetation.
- Coastal grazing marsh and wet pasture just behind the sea wall.
- Sheltered bays and inlets that escape the worst of the swell.
Timing matters more than location. Arrive two hours either side of low tide, when the mud is open and feeding is at its busiest. In winter, dawn and dusk are especially productive, and a rising tide pushes birds closer to the shore, where you can watch without disturbing them.
Reading the Curlew's Vocabulary
A curlew is not a one-note bird. Once you separate the sounds, you can often tell what a bird is doing without seeing it.
- The bubbling song. A rising, rippling series of notes, often described as cur-lee repeated and accelerated. Breeding birds give it on territory and in display flight. If you hear it inland in spring, you are hearing something increasingly rare.
- The "cur-lee" call. A clear, far-carrying two-note whistle. This is the bird's everyday contact and alarm call, and the one most people recognise.
- The "coor-ee" or wailing note. Softer, more drawn out, often given by birds on the move or settling on a roost at dusk.
- A sharp, clipped alarm. Brief and insistent, usually meaning you, a dog or a raptor has come too close.
- Whimbrel confusion. A smaller cousin passes through on migration in spring and late summer. Its call is a rapid, rippling titter of seven or so notes — faster and lighter than the curlew's, and it usually flies with quicker, shallower wingbeats.
A decent pair of binoculars and a notebook will teach you more in one season than any app. Write down the call, the time, the tide state and what the bird did next.
Fieldcraft That Helps the Birds
Curlews are wary, and disturbance costs them energy they cannot spare. On cold January days, every unnecessary flush means calories burned for nothing. A few habits make a real difference.
- Keep your distance. Use a hedge, sea wall or hide as a screen rather than walking straight across open mud.
- Watch the tide line, not the birds. Settle somewhere the rising water will bring birds towards you.
- Keep dogs close and on a lead around estuaries and roosts, especially between October and March.
- Avoid roost sites at dusk. If a flock is gathering, watch from well back and let them settle.
- Stay off upper mud and saltmarsh where birds feed and where nests may be hidden in spring.
Why These Birds Need Protection
The curlew is now one of the UK's most threatened breeding birds, and the reasons are cumulative rather than dramatic. Drainage and agricultural change have reduced the soft, invertebrate-rich ground they need. Predation of nests and chicks has risen in some landscapes. Disturbance on winter estuaries adds further pressure. Because curlews are long-lived and slow to breed, small annual losses quietly become a collapse.
Protection works at several levels. Estuaries designated for their wildlife value give legal safeguards, and many are managed to keep roosts undisturbed. Agri-environment schemes pay landowners to delay cutting hay and keep damp pasture wet. Predator control and nest protection operate in some upland strongholds. But the simplest contribution any of us makes is to be quiet, distant and predictable in the places these birds rely on.
Making a Slow Season of It
Learning curlew calls is a good excuse for the sort of country pastime that asks nothing of you but time. Walk the same estuary path through the winter. Notice how the soundscape shifts: October's scattered contact calls, the soft wails of a December roost, the first bubbling songs of February as birds begin to think of the hills.
Take a flask, a notebook and patience. Sit still long enough and the mudflat stops looking empty. Curlews appear as grey shapes against grey water, bills working steadily, and that strange, lovely bubbling drifts across the estuary. It is one of the finest sounds in Britain — and worth every effort to keep it there.
