We thought these two comparative photographs might be useful. The Mottled Grey picture taken on the earlier date of 14.02.15 and the Early Tooth-striped this morning.
We went on a course to Scotland with David Brown four years ago and there was much discussion on how to tell the differences between these two moths. John Knowler, a Scottish County Moth Recorder was also present. They said first of all look at the shape. The Mottled Grey is triangular and the Early Tooth-striped arrowhead-shaped as demonstrated in these photos.
The Mottled Grey is shiny when fresh, has chequered veins on the fore-wing and there are chevron markings on the distal cross line. The male MG has bi-pectinate antennae whereas in the male ETS the antennae are straight strands. As you know MG emerges slightly earlier but their flight periods overlap!
Carolyn & Evan