Wildlife experts are launching a UK-wide bug count to try to discover why bird species are on the decline.
Throughout June, the Royal Society for the Protection of Birds (RSPB) is asking drivers to use a simple grid to monitor the insects hitting their cars.
The Big Bug Count uses a "splatometer" held over a licence plate at a journey's end.
By pooling the results, scientists hope to see whether a supposed decline in bugs can be linked to a fall in bird numbers in particular areas.
The count will also provide a snapshot of the state of Britain's insects, which can be compared with surveys in future years.
RSPB spokesman Andrew South said: "It's a very simple way for families, or anyone, to give us information about Britain's insect population."
The reasons why there may be fewer insects around are not yet known - theories include habitat loss and pesticides.
The Big Bug Count will not identify causes of insect declines but will provide a first step in helping to monitor future changes in the abundance of flying insects across the UK.
THE BIG BUG COUNT
There are more than 23,000 insect species in the UK
Worldwide there are maybe 4-6 million more
Insects are needed for pollinating crops and plants
A swallow needs to eat thousands of insects a day
The charity hopes to produce a geographical breakdown of the areas in the UK which appear to have the highest number of insects and where numbers are falling.
Mr South said: "I remember going on holiday to the West Country as a child and my dad having to put the windscreen wipers on to clear the insects. That doesn't happen any more."
However, scientists point out this may have more to do with the aerodynamic changes made to cars in past years than to any real decline in insect numbers.
This is one of the reasons why the splat count is being made on the registration plate - a vertical surface - and not on windscreens, which vary in shape across vehicles of different design.
Mr Smith said: "We have noticed a particular decline in the number of spotted flycatchers, which winter in Africa and come back to this country during the summer. This must have some correlation with the decline in insects.
"Even birds which are generally seed-eaters, such as sparrows and finches, need insect food at some stage. Just after hatching, for example, they need a massive injection of protein that they can only get from meat.
HOW TO WORK THE SPLATOMETER
1. Clean your licence plate
2. Note your mileage and time
3. Make a 20-80-mile journey
4. Count splats with RSPB grid
5. Report findings online
"Insects are an integral part of our ecosystem. Even birds and animals that don't rely on insects directly rely on animals that do."
The RSPB website has an online survey form with a printable splatometer template to cut out. Alternatively, would-be bug counters can call the hotline on 0870 787 5577 before 21 June 2004.
The splat data can be collected on any journey (preferably between 20 and 80 miles) taken during the month (day or night). It would be better if the journey is completed in dry weather, as rain during the trip could wash insects off the number plate.