American Bittern Botaurus lentiginosus: an historic first for Essex Saffron Walden Poor Rate at 4 6d in the Pound Lady Day 1820 to Michaelmas 1820 [Hand-written text detailing street name, individuals, Rental, Amount due, Default and Received.] BRIDSON, G.R.D, HARVEY, P.A. & PHILIPS, A.C. (1980) Natural History Manuscript Resources in the British Isles. Mansell, London. CHRISTY, R.M. (1890) The Birds of Essex. Essex Field Club. CLARKE, J. (1 839). Magazine of Natural History, III: 99. COX, S. (1984) A New Guide to the Birds of Essex. Essex Bird Watching and Preservation Society. FITCH, E.A. (1895). Obituary of Joseph Clarke. The Essex Review V:205-210. GLEGG, W.E. (1929) A History of the Birds of Essex. London. HUDSON, R. & PYMAN, G.A. (1968) A Guide to the Birds of Essex. Essex Bird Watching and Preservation Society. KELLY (1845) Kelly's Directory of Essex. MARGARY, H. (1975). The Old Series Ordnance Survey maps of England and Wales. Vol. 1. Headley Brothers Ltd., London. NAYLOR, K.A. (1996) A reference manual of rare birds in Great Britain and Ireland. Vol. 1. Nottingham. PIGOT & CO. (1823-4) Directory of Essex. PIGOT & CO. (1832-3-4) National and Commercial Directory. PIGOT & CO. (1839) National and Commercial Directory. REANEY, P.H. (1969) The Place-Names of Essex. Cambridge University. SEEBOHM, H. (1883-5) A History of British Birds and their Eggs. 4 vols. London. SEEBOHM, H. (1886) Coloured Figures of the Eggs of British Birds. Pawson & Brailsford, Sheffield. YARRELL, W. (1843). A History of British Birds (1st edn). London. Essex Naturalist (New Series) 19 (2002)