Straw dot moth

This little moth, which I think is the straw dot Rivula sercealis, turned up in our garden last week. 

The books say that it's mainly a heathland and moorland species, breeding in grass species that we don't have in our garden, so maybe it was just passing through. 

Apparently, as a resident species it has a southern distribution in the UK, where it's common, but it's more local in the north and there is mostly found in the north-west. 

There are suspicions that the occasional northern specimens are immigrants from Europe, which seems remarkable for such a small moth that's less than 15mm. long. It seems to be a worn specimen, paler than would be typical, and seems to have lost the darker edges to its hind wings ..... perhaps the signs of a long-distance traveller?

Tom Dunn and J.D.Parrack, in their Moths and Butterflies of Northumberland and Durham, mention instances of it being taken in moth traps in the early 1980s in Hamsterley forest, which is only a few miles away from our garden.