Can we update old sayings?

There's this Dutch saying about birds in May:
'In mei legt iedere vogel een ei': "In May every bird lays an egg".

I think this saying needs updating. First of all, I'm pretty sure that it isn't true. I don't think male birds will lay an egg. And many birds will lay more than one egg.

What I do think applies to every bird, at least all birds in my vicinity, is that they s@#t more in May. But why oh why do they always have to do that on my car?