Leaf Weevil damage - Birches, Sorbus, Quercus Oak, Fagus - Beech.
Holes and bits out of leaves. 

The common Green Leaf Weevil

Leaf weevils come in many different colours and shapes. Basically they are all slow moving beetle type insects.
In UK, The green Leaf Weevil is a common pest of Oaks, Birches, Sorbus and Beech - causing damage to leaves. The Green Leaf Weevil can be present in large numbers, but rarely stay around for long after they have caused the initial damage  (Which can happen quite quickly).

Edges of leaves are mostly damaged, though sometimes with holes in the leaf. It is normally active in late spring early summer. It's damage is not confined to those trees listed above. Other trees can also have leaf damage. As with the Vine Weevil Beetle - a far greater pest in the garden - the larvae feed on roots during the winter months.

The leaf weevils are quite attractive, with their Metallic Green colouring. Don't be fooled!

Difficult to treat, but a contact spray of Bifenthrin, or systemic spray (Not too effective on large trees) of Provado.