No dead flies on the car

I was driving along today, quite bright and sunny with quite a few butterflies about.

I know there were quite a few butterflies around 6 died on the windscreen and it got me wondering, as you do. Have flies become smarter?

In the mid '90s I drove regularly, long distances on the motorway, following my hobby of mountaineering and climbing, another story another day.

After most of these journeys the car headlights and windscreen would be a mosaic of dead flies and sundry insects. Now when I drive, I rarely have more than one or two insect corpses on the car.

Is the fly population decreasing, are car shapes less conducive to fly collisions, or have flies just become smarter?

The dead fly syndrome isn't one I miss, but just want to clear up in my mind.