A few years ago I had been surprised to find a flattish yellow sluglike creature, about two inches long, under a stone in my garden. A bit of research showed that it was the Australian flatworm, Australoplana sanguinea, an alien species which appeared in the UK (in the Scilly Isles) in 1980, but has since been found across the country. There is some concern about these flatworms as they are earthworm predators, and DEFRA advice is to trap them with flat refuges and destroy as many as can be found. They are listed on schedule 9 of the Wildlife and Countryside Act, which makes it an offence to deliberately release them into the wild. This winter I’ve seen a few more, in the same spot in my garden, but this time I had my camera to hand and was able to observe the creature closely. Reminiscent of a leech, it stretches its head end out and waves it over the surface in a search pattern, looking, presumably, for its prey, or indications of it. After a few minutes it must have found some sort of trail because it turned round through 180 degrees and headed directly towards a worm-hole in the soil substrate. It disappeared down the hole in about a minute, presumably in search of its prey, and didn’t emerge in the half-hour that I watched afterwards. The following evening I encountered two more, which are now in a moss-filled pot in my office, waiting for a suitable experiment to suggest itself!