a boldly striated plumage that blends Secretive, mouse-like, with herbage in of the ithardest the Grasshopper beautifully with the ground which nests, Warbler Locustella naevia presents one nest-finding challenges in Britain (Campbell & Ferguson-Lees 1972). Not surprisingly, therefore, the species has been little studied in Britain, though the 'Breeding Atlas' (Sharrock 1976) showed it to be widely but thinly distributed throughout most of England, Wales, southern Scotland and Ireland, except in most upland areas.In Britain, the main earlier investigation was of over 200 nests found in Sussex by Walpole-Bond (1934). This paper adds further to our knowledge, by drawing on information from three major sources. Foremost, it examines 261 nest histories submitted to the British Trust for Ornithology's nest record scheme during 1941-86, then 20 nests detailed in the diaries of the late A. Whitaker during 1909-48, plus observations made by the author at six nest sites in Hampshire and Buckinghamshire. Where relevant, a comparison is made with the findings of local studies on the Continent, including those in France by Labitte (1949), Vaucher (1961) and Henry (1972), in Sweden by Swanberg (1945), and in Luxembourg by Hulten (1959). Distribution of records The 261 nest record cards cover 46 counties and most of the regions shown by the Breeding Atlas to be supporting Grasshopper Warblers (figs. 1 & 2). A few counties, notably Oxfordshire (46), but including Lancashire (33) and Somerset (19 cards), are particularly well represented, as a result of nest-finders who concentrated their efforts on this species. Wales