The wings are orange-yellow with a varying degree of speckling. The outer of the two cross-lines on the forewing sweeps in a gentle arc ending at least three quarters of the way along the leading edge. This species could be confused with other similar thorn species – the Dusky Thorn, August Thorn and September Thorn.

The larvae can be seen from early May to July. Overwinter as eggs on the foodplant.

Size and Family

  • Family – Thorns, beauties, umbers and allies (Geometridae)
  • Medium Sized
  • Wingspan Range – 32-40mm

Conservation Status

  • UK BAP: Not listed
  • Common

Caterpillar Food Plants

Downy Birch (Betula pubescens) and Silver Birch (Betula pendula), Alder (Alnus glutinosa), limes and elms.

Habitat

Woodland, scrub, parks and rural gardens.

Distribution

  • Countries – England, Wales, Scotland and Ireland
  • Generally well distributed and frequent throughout England, Wales, mainland Scotland, Ireland and the Channel Islands. Fairly widespread but not frequent on the Isle of Man.
Canary-shouldered Thorn by Iain Leach

Canary-shouldered Thorn

Canary-shouldered Thorn by Iain Leach

Canary-shouldered Thorn

Canary-shouldered Thorn by Garry Barlow

Canary-shouldered Thorn

Canary-shouldered Thorn (underwing) by Bob Eade

Canary-shouldered Thorn (underwing)

Canary-shouldered Thorn by Rob Blanken

Canary-shouldered Thorn

Canary-shouldered Thorn (closeup) by Patrick Clement

Canary-shouldered Thorn (closeup)