Similar to Light Orange Underwing (Boudinotiana notha) [Poppeldagmåler] which can also be seen on Amager. But has a large middle spot on the upper forewing and well-marked white markings on the forewing as well. BN prefers aspen trees.
Finally succeeded finding one of these daytime flying moths that appear through early spring; and sometimes are confused with Small Tortoiseshells also flying early in the spring.
Imago. The large black middle spot on the upperside front wing indicates that this is of this species and not the Light Orange Underwing (Boudinotiana notha) which can also been seen in the area; and also is flying at daytime, though it prefers aspen trees rather than birches.
A worn and probably old individual that didn't fly well.