Bright red cars attract more bird droppings than vehicles of any other colour, according to a recent study.
The Halfords study recorded the frequency with which birds left their mark on cars in five cities around the UK, and found crimson motors were targeted the most.
Green cars were found to suffer least, followed by silver, while white vehicles escaped more often than black in the analysis of 1140 cars in Brighton, Glasgow, Leeds, Manchester and Bristol over two consecutive days, to see whether colour made a difference to birds.
During the study, drivers were also asked how quickly they removed droppings from their cars. Only 17 percent, or one in six, said they wiped off deposits immediately when they saw them, 20 percent said they took action "within a couple of days", while 55 percent waited until the next car wash. The remaining eight percent never washed their cars or left it to others to organise.
As well as being unsightly, insurance industry figures show bird droppings on vehicles can be an expensive problem.
Halfords car cleaning expert David Howells said: "This research does have a serious side because the problem annoys drivers, causes damaged paintwork and affects the value of vehicles. To protect your bodywork from damage, droppings should be carefully cleaned off as soon as possible."
Theories abound on motoring and social networking sites as to why birds are attracted to pooping on some cars more than others. A Lexus driver reckoned newly polished cars suffer because birds see a reflection of themselves. A Ford Focus owner agreed and said the darker the colour, the deeper the reflection and the more violent the reaction. An Alfa Romeo owner said it depended on where you park and a Mercedes driver said blue was the worst as it reminded birds of water.
Others thought birds saw red as a danger or went for similar colours to their own plumage, such as in seaside resorts, where seagulls went for white cars, while in cities pigeons go went for grey.
Researchers who compiled the results found 18 percent of red cars were marked with droppings, blue 14 percent, black 11 percent, white seven percent, grey/silver three percent, and green one percent.
Car polish experts Autoglym said the damage to vehicle paintwork arose not from the acid or alkali in bird faeces, but from paint lacquer softening and expanding to form an uneven mould around the dropping, which produced a dull patch. Grainier textures from seed-eating birds produced the most blemishes, so pigeons are worse for motorists than seagulls.
Autoglym said that bird dropping damage could only be prevented by owners removing the poop as soon as possible.
The British Trust for Ornithology was more circumspect on the role of colour in the "drop zone" for birds.
"We do know that birds can be attracted to certain colours during display but it [droppings on cars] is probably more to do with where you park; if you park where birds roost, then you are going to get more droppings on your vehicle," said a spokesperson.