It is about the size of a postcard

The idea is to work out whether anecdotal evidence of declining numbers of insects can be supported.

The Royal Society for the Protection of Birds (RSPB) says species like tree sparrows and corn bunting are on the decline.

It wants to know whether the apparent decline in the number of bees, ladybirds, moths and other insects has anything to do with this.

So the society has developed a postcard-sized bug-catching device which drivers can use to sample the number of insects they encounter on a journey.

"If people across the country do this, we'll be able to develop a picture of the regional trends in insects and, if we do it through the future, any temporal changes as well," said the RSPB's Richard Bradbury.

Automatic analysis

The results of the research may help to determine how far insect numbers influence the numbers of birds.

"Lack of insects could affect bird populations but I think there are a number of other things as well, for instance global warming might affect the distribution of birds within the country," said the Wildfowl and Wetlands Trust's Pat Wisniewski.

Numbers are falling for some bird species

The splatometer consists of a rectangular shaped piece of PVC which is attached to the front of a car.

After a journey, the PVC rectangle is covered with an identical piece of plastic and sent off for analysis.

The bug-splattered pieces of plastic are analysed by computer software which records the number and type of insects killed.