Then we start to see the grassland butterflies like the meadow brown, ringlet and small skipper, which make just one appearance in the year. By contrast, most of the spring flying butterflies, such as the brimstone, small tortoiseshell and peacock, laid eggs which will produce a further generation from mid-July to September.

From about mid-June into July you will find butterflies increasingly favouring bramble and thistle flowers in their search for nectar, always preferring plants in warm sheltered places.

The recent arrival of millions of painted lady butterflies flying in from North Africa should also ensure a further appearance of that species, probably in August. Once mated and with eggs laid on thistles, new painted ladies can hatch within six to eight weeks of an immigration, although this is weather dependent. As far north as Yorkshire, it often takes a bit longer.

The current arrival of painted ladies looks like being one of the largest ever recorded. My wife and I travelled by road to Coventry at the height of the movement at the end of May and were struck by the fact that these butterflies were crossing the route all the way along and always flying north-westward in long lines.

Later in the day, we took a leg-stretch in a Coventry park and discovered a line of movement conveniently close to a bench. We returned whenever possible over the next three days and did several hour-long counts. Butterflies were passing this point from 11am to 5pm or later at a steady rate of one very two minutes, and they were using the same flight-line over several days.

At the same time, similar immigration lines were being recorded all over Britain.

During the last big arrival of painted ladies in Yorkshire in 1996, one observer near Bridlington had a continuous stream passing through his garden for four hours at the rate of one per second. That's an estimated passage of 14,400 butterflies.

While many of the current arrival of painted ladies have now settled, some fly on ever north-westward and a few might even reach Iceland.

Recent days have seen yet more painted ladies arriving, together with other immigrant butterflies such as red admirals and even a few much rarer clouded yellows.

Migratory moths are coming in at the same time, including the silver Y and the tiny diamond-back, both daytime fliers. Silver Ys are annual immigrants and a notable pest species on garden plants and vegetables! You can often pick them out by their fast-beating wings resulting in a haze of grey-brown as they move about. Look out for the variably-shaped, pale wing mark, which gives them their name.

Although Butterfly Conservation emphasises butterflies in its name, it records and conserves moths with equal enthusiasm. It is particularly interested in records of hummingbird hawk moths, another immigrant from the Mediterranean. This small but chunky daytime-flying moth looks just like a miniature hummingbird.

It is quite fascinating to watch one hovering in front of nectar plants, using an amazingly long proboscis to suck out its food. It can be seen in any month of the year, although in Yorkshire more likely during high summer. It particularly favours geraniums. You can send records in via www.butterfly-conservation.org

Our Yorkshire branch of Butterfly Conservation works with the Yorkshire Naturalists' Union to produce an annual report on the county's butterflies and moths.

The latest edition (covering 2008) is due from the printer in early July. It runs to 112 pages and is packed with some 80 colour photos, together with the latest distribution maps and hot-off-the-press information about the many changes taking place among Yorkshire's species.

n Members of the above organ-isations get their copies free as part of their membership packages, but we have a few copies to sell at £11.50 (inclusive of p&p). Order now from Butterfly Conservation Yorkshire, c/o 10 Chellsway, Withernsea, HU19 2EN and expect delivery in the second or third week of July.

Howard M Frost is Butterfly Conservation's voluntary organiser of butterfly recording in Yorkshire and can be contacted via Butterfly Conservation's Yorkshire website: www. yorkshire butterflies. org.uk where you can also find the latest butterfly and moth news, and report sightings.