Caterpillars on Oak Trees

Several people are contacting the Ranger's Office about the small green caterpillars that are emerging on the Oak trees across the Commons this week.

There are several species of moth caterpillar that feed on the Oak trees and two of these are around at the moment: the caterpillar of the Winter Moth and those of the Green Oak Tortrix moth. The caterpillars are now starting to emerge and you will likely see them hanging on very fine threads from the Oak trees, always seeming to hang at head height and tangle themselves in your hair!

                                                       Winter Moth caterpillar

Please be assured that both caterpillars are harmless.  They are a very common moth in many parts of Britain and although the larvae can become a pest, they have never become a problem for our Oak trees here on the Commons. 

Despite seemingly being able to eat their way through a significant amount of Oak leaves, the trees are well able to deal with this and, even if denuded of the first flush of leaves, they will produce what's know as "Lammas leaves", a second flush of growth during July and August and will make a full recovery. 

Great tits and blue tits feed their young on Winter Moth caterpillars and will time their breeding to coincide with the moth’s lifecycle.

The Green Oak Tortrix moths will emerge in a few weeks and if you gently shake an Oak tree and you will be surrounded by a cloud of this beautiful, delicate little moth.  The Winter Moth caterpillars will pupate over the summer and emerge from about October.

If you have any concerns or queries about any wildlife you see on the Commons, do call us on 020 8788 7655