104782 Grasshopper Warbler Locustella naevia L 13cm. Skulking, unobtrusive warbler, heard more often than it is seen. Sexes are similar. Adult has streaked olive-brown upperparts; underparts are paler but flushed buffish brown on breast. Long undertail coverts are adorned with dark streaks. Juvenile is similar but underparts are usually tinged yellow-buff. Voice Utters a sharp tssvet call. Song is reeling and insect-like; sung mainly at night. Almost inaudible to people with poor hearing. Status Local summer visitor to rank grassland with bramble patches and clumps of rushes.