Spring is alive when the oystercatchers start chasing rivals off territories. Two birds twist and turn up and down the beach in close formation. This frenzy is in marked contrast to the roosting turnstones and a single knot that quietly sit out the high tide on the wooden groynes. At the peak of the flood, Brent geese arrive in great flocks to forage on the drowned saltmarsh; here there is also the usual flock of curlews and scattering of redshanks that make short, noisy dashes low over the marsh.