The Grasshopper Warbler (Locustella naevia) has a high-pitched insect-like reeling (hence the common name) performed at dawn and dusk. The sound - tschick, tschick - has been likened to mill wheels, spinning wheels and fishing reels. The rapid, uniform high-pitched trill of this warbler is unmistakeable once heard. The upper-parts are pale olive-brown, each feather having a central darker brown streak. The cheeks are greyish, the irises are brown and there is a faint eye streak behind the eye. The beak's upper mandible is dark brown and the lower mandible yellowish-brown. The underparts are cream-coloured or yellowish-buff with a few dark brown spots and streaks on the breast and flanks. The wings are brown with the outer edge rimmed with paler brown. Tail feathers are reddish-brown with faint transverse bars being visible in some individuals and the under-tail coverts are streaked. The slender legs and the feet are pale yellowish-brown.