Mourning Doves and White winged doves

I feed the birds outside and these two types of birds and the ones that come and eat the most. I feed them alot and our cats like to watch from a window and I love to watch as well. I think the birds recognize me and know im the seed lady. Ive started noticing something.

When I dont put seed out or skip a seeding... they come and flutter their wings on the window. They come and essentially tap or knock the window with their wings face or beaks. My fiance said he thinks theyre crashing into the window and that absolutely has happened, we've buried two birds over the course of two years for window crashes.

Is this what theyre doing? Or are they crashing into our window because we dont have window clings on?

I hope I dont sound silly thinking theyre trying to knock or get our attention. Its just that theyve never ever done it so gently and in a controlled way, theyve always just went full speed into the window like its sky. Theyve also never done it while I wasnt feeding them.

Every time they fluttering the window I go out and put seed which makes me think thats why they knock? But like I mentioned, my fiance doesnt think theyre trying to tell us theyre hungry he thinks theyre crashing.

Is it possible these types of birds are smart enough to try to communicate with me a need they have?

P.S, window clings arw in the mail rn, I domt want any other crashes that end badly but im still curious as to what I think they mightve been doing.