IN the last couple of weeks there's been something of an explosion of moth activity in our garden. I first noticed this last weekend, when the thermometer nudged above 20 degrees Celsius for what seems like the first time in weeks.

I was suddenly aware of several moths buzzing around the late-flowering plants, which are usually attractive to hoverflies at this time of year. On closer inspection these turned out to be Silver-Y moths which have the rather grand scientific name of autographa gramma.

The Silver-Y moth is a rough, marbled mixture of black, brown and white. When at rest its most distinctive feature becomes obvious - a small, metallic Y-shaped mark on the forewing.

The Silver-Y moths that are currently frequenting our garden are restless and always seem to be on the move, flitting from one flower head to another in search of nectar.

This species is actually an immigrant from mainland Europe, which can often be abundant in Yorkshire, especially after southerly winds. Some of the early arriving migrants stay to lay eggs in Britain, producing locally-bred later generations of adult moths.

The Silver-Y moth is active in the day and at night, but many other moth species are very much nocturnal creatures. The best way to see a wide variety of moths is to join a moth group that puts out special lights to attract the insects after dark.

This Saturday is national moth night, and Craven Conservation Group is inviting people to join them at 7 pm at the Hoffman Kiln car park near Langcliffe for an evening in the company of these intriguing and often beautiful insects.

We have recently returned from a holiday in Norfolk, which has witnessed an invasion of one of the most spectacular day-flying moths, the Hummingbird Hawk-moth. We saw this insect visiting silene flowers in people's gardens, and this fascinating species does sometimes find its way to Yorkshire, so it's well worth looking out for this mini helicopter in your garden. It flies around with an audible hum, but its wings move so quickly they are just a blur.

If you're visiting the coast, you may also see large numbers of newly-arrived Silver-Y moths and other migrant species. Occasionally, at observatories such as Spurn Head in the extreme east of Yorkshire, there is a frisson of excitement as some exotic moth from distant shores is picked out of the trap.

One of the most evocative-sounding moths in this category is the Death's-head Hawk-moth, sure to give some moth observers the creeps in the depths of night!

Let me know what's been happening with the insect life in your garden.