As Boom and I walk the paths and lanes deep in Iceni territory, we see and hear the regular inhabitants of the trees and hedgerow: robin, dunnock, songthrush, blackbird, wren, chaffinch, blackcap and chiff chaff. Goldfinches hustle about in their chattering groups. Overhead, swallows duck and dive and gulls soar. But as April moves into May and June is on the horizon, where are the willow warblers? They should be easy to see or hear. After all, if you refer to your handy fiel