Reed bunting – Emberiza schoeniclus
Reed bunting is a passerine bird in the bunting family Emberizidae, a group now separated by most modern authors from the finches, Fringillidae. It breeds across Europe and much of temperate and northern Asia. Most birds migrate south in winter, but those in the milder south and west of the range are resident. It is common in reedbeds and also breeds in drier open areas such as moorland and cultivation. The common reed bunting is a medium-sized bird, 13.5–15.5 cm long, with a small but sturdy seed-eater’s bill. The male has a black head and throat, white neck collar and underparts, and a heavily streaked brown back. The female is much duller, with a streaked brown head, and is more streaked below.

It sounds like this
Recording by Dave Curtis from Xeno canto