Sitting on a Dorset beach on a warm August day,I became aware of an occasional large white butterfly flying in fast from the sea,carrying on up the beach and finally homing in on the cliff face vegetation.

They would quickly need to top up their energy levels after the long flight across the channel.

That was a couple of days before the remnants of hurricane Bertha roared in and the ensuing gale curtailed butterfly activity for a week.

Clearly those butterflies were migrating from northern France but the influx was very limited and nowhere near on the scale of centuries ago when reports frequently spoke of "inumerable swarms of white butterflies coming in,as thick as flakes of snow and blotting out the sun for hours on end".

Our last notable migration occured about five years ago when billions of painted lady butterflies flew in over several days and spread throughout the country.The clouded yellow is another spasmodic migrant with 1947 and 1983 being exceptional years.

Some species of moth also make tracks for Britain and its amazing how such seemingly fragile looking insects are capable of flying hundreds of miles.They are able to alight on a very calm sea for a few seconds to imbibe salts,a phenomenon I've actually witnessed in the Channel Islands.

In the same Dorset location a few years ago I watched swarms of harmless wasp lookalike hoverflies flying up the beach,up the cliff face,up the hotel front,over the roof and on inland.The swarms continued night and day without any let up for the whole ten days I resided at the hotel.An incredible sight.