Moths and Cuckoos

Whilst poking around in some nettles and long grass I came across a caterpillar that I didnt recognise. It was immensely hairy, amazing colours and moved fast. Knowing that these hairy chaps can be cause irritation on the skin, I grabbed a leather glove and picked it up to get a better look. The height of the white bristles make the caterpillar nearly as high as it is long- quite a specticle. I tasked the kids to go and get my copy of Jim Porter's Colour Identification Guide to Caterpillars of the British Iles (which I throughly recommend), and the specimen was identified! The caterpillar turned out to be a Garden Tiger, a type of colourful moth thats on the wing in July, and according to Butterfly Conservation whilst still widespread and common is in decline. It eats a wide range of plants, including nettle, dock and hounds tounge so loves the edge of an untidied hedge.

But there's another reason why I am interested in this and other hairy caterpillars - they are the favoured food of one of our most well known and also declining birds, the Cuckoo. Earlier in the year I was reading Rebirding by Benedict Macdonald. This is an amazing but alarming book about the history of the decline in the UK's wildlife, but also about some of the solutions and most inspiringly what we could have (but have forgotten it was ever here). It has a whole section about Cuckoos, and he reckons your average Cuckoo will need to consume upwards of 150 hairy caterpillars a day or 11,250 during its brief stay in the UK. Cuckoos have evolved to be able to slice the caterpillar, shake the toxic bits out, and then regurgitate the hairy part as a pellet. They are the perfect hairy caterpillar specialist.

We are lucky and seem to live in a bit of a cuckoo hotspot. We have some great habitat next door in the reed beds of Cleveland Lakes (where they target Reed Warbler nests), however we regularly hear and find them on the farm where they are probably after Dunnock nests. But can our farming system provide them with the food they need? Well, apart from Garden Tiger, Cuckoos also like Drinker, Oak Eggar, Magpie and White Ermine moth caterpillars - all of which I have happened upon or caught in a light trap here on the farm. So whilst I can't estimate the quantities of cuckoo fodder we produce, we appear to deliver a good mixed variety. Long grass margins, lots of hedges, cows and not using insecticides appear to be the key.