In Britain there are only 59 species of butterflies, a tiny proportion of the approximately 20,000 species worldwide.

Well loved (except perhaps for the whites), found in urban and rural areas, and relatively easy to identify, they are ideal subjects for public surveys.

Butterfly Conservation organise just such a survey every year, asking people to send in sightings of 20 butterflies (and a couple of moths) in the middle of summer.

This year over 44,000 people provided nearly 600,000 records, making this the biggest butterfly survey in the world.

The results show the usual wild swings beloved of the statisticians but confusing to you and me.

The fourth most numerous butterfly was the small tortoiseshell, its numbers well up on last year, even though the population is only about a fifth of what it was in the 1970s.

The most numerous species was the peacock, although its numbers were down by a third from last year.

Others doing well were small and large whites, gatekeeper, meadow brown and red admiral.

Tellingly the average number of butterflies per count dropped from 23 to 15, and only six species increased their numbers whilst 15 declined.

Some good news though is that our butterflies seem to be continuing the recovery made in 2013 following the very wet summer of 2012.

Butterfly Conservation’s Richard Fox said: ‘After a good summer in 2013, the big question this year was whether butterflies would continue to recover and build up even greater numbers or slip back again.

"Thanks to another amazing turnout from the public, we know that the answer is a real mixture."

The problem with annual surveys is that too much is often made of short term variations, especially by non-specialists: a ‘bad’ year followed by a ‘good’ year is hailed as a problem solved.

The fact that there will always be changes in numbers from one year to the next is overlooked.

The trick is to study the figures over a longer period, try to discount these natural variations, and identify what is really happening to a population.

This is exactly what organisations like Butterfly Conservation do.

For butterflies in general we can say, therefore, that overall the news is not good.

Short term winners and losers mask long term declines.

• For more information go to butterfly-conservation.org .