On a bright day the high tide has flooded the saltmarshes, the wind is quiet and the waterbirds wait for the water to drop; a black-headed gull finds the tip of a rock and claims it, waits and then finally drops on to the exposed causeway to Northey Island. Turnstones arrive and work the seaweed-covered rocks for invertebrates. A handful of redshanks fly to the exposed mud and curlews lift from the saltmarsh. A small, bright white flock of avocet flies up the estuary to a favourite island close to Maldon, where hundreds of redshank are tucked up on the saltmarsh banks and teal huddle and swim in the muddy gullies.
At low tide, a harsh northerly blows across the estuary, the great expanses of soft mud are empty of birds. Small flocks of teal with a handful of wigeon roost in the lee of deep, sandy gullies and curlew and redshank shelter in the saltmarsh. There are a handful of shelduck but no Brent geese yet. Under the blanket of grey sky, a single red kite floats along the sea wall like a harrier before veering across the flat land of fallow fields and farms.