I have had a request to repost my recent photographs of these into a new thread that can be made 'sticky'
#1 A young caterpillar wandering around its nest
#2 A well used nest newly abandoned
#3 On the move
#4 As close as I was going to get!
By way of excellent explanation about the dangers of these critters the following is a quote by MandyandDave in their previous thread
"Processionary Caterpillars are so called because they form processions, nose to tail, as they leave the nest prior to changing into moths. They are found in all Mediterranean climatic areas, ranging from Portugal in the West through to the Adriatic and beyond in the East. The "nests" are fist sized or larger balls of spun filaments, usually lodged in fairly high branches of pine trees, and yes, many campsites in all of these countries border onto or are within pine forested areas!
The months from October through to March and April see the time when the caterpillars descend from the cocoon nests and they will then form "processions" in search of food sources. These can be hundreds of caterpillars nose to tail, winding along roadways, paths, grass, whatever. The caterpillars have poisonous and irritant brittle hairs on their bodies, and are a mottled dull brown with faded yellowish splotches, a standard nature danger signal!
In adults these hairs will cause severe skin irritations, and occasionally anaphylactic shock, closure of airways leading to death, and obviously requiring immediate medical treatment. In children, (who are more inquisitive about the processions and may handle the caterpillars then transfer the fingers and hairs to the mouth etc) the effects can be more immediately severe and will almost always require immediate professional medical aid. Similarly, older people with less resistance can also be quickly affected. Golfers, tennis players, footballers and bowlers (petanque and boules) should be careful NOT to handle a ball that has gone through a procession, golfers should check local rules, some courses permit substitutions. Golf, Tennis, boules and Footballs should be cleaned with disposable cloths which should then be burned as a means of disposal.
For pets, dogs and cats, the problem is that the caterpillars have a bittersweet smell and taste, and both dogs and cats will try to eat them. The results are almost certainly fatal, as little as three or four will kill a medium sized dog, and one may produce death in a cat. The reaction to the poison also causes necrosis of the tongue, and by the time the owner notices the problem, it is usually too late for veterinary treatment to do much except ease suffering.
Local advice is that brushing a procession away can cause more problems than it solves, this spreads the irritation producing hairs and the risk of poisoning actually becomes higher as a result.
French research indicates that GLOBAL WARMING is affecting the spread and range of these caterpillars, and they are now being reported as far north as the Loire and Seine valleys, spreading from the Pyrenees and the Massif Centrale. Best advice is take care and avoid letting your pet run free near pine woods, even on those "pain in the butt" long leads."
Please be aware of these nasty little things.