Local in oak woodland throughout much of southern England and southern Wales, north to Yorkshire. Fairly frequent in south Hampshire, but uncommon in north Hampshire and on the Isle of Wight. Wingspan 14-18 mm. The main confusion species are
Y. lucella, from which
Y. alpella can be distinguished by the thorax being concolorous with the base of the forewing, and by the presence of fasciae, although on worn specimens these can be inconspicuous; and
Y. sylvella from which
Y. alpella can be distinguished by its smaller and less conspicuous fasciae, and by the paler ground colour of its forewing (MBGBI Vol 3). Larva feeds on Oak, beneath a silken web, over-wintering as an egg.