Male Reed buntings are relatively easy-to-identify, similar in size to House sparrows, albeit with striking black caps and dark, drooping moustaches. Female Reed buntings, in contrast, are lighter brown in colour, and do not display the black cap so typical of the male. Whereas males have a much brighter white underside, females are more uniform brown. Both sexes have brown and black streaked backs with long tails. You can see the difference between the two in the comparison images below.
The Reed bunting bill is sturdy and strong, ideal for breaking open and consuming seeds, although it is still quite small. In fact, it would be easy to categorise these birds as a type of Fringillidae (i.e. Finch), although most modern authors classify them as Warblers.
They are resident all year round in the UK, apart from the northernmost parts of mainland Scotland where they are just summer visitors, and there is a small isolated pocket of Scotland just below Inverness and most of the Cairgorms National Park that do not receive any visits from Reed buntings.