How often should I expect crows to visit?

Hello! I am relatively new to this community, though I've been lurking for a while. I have been trying to befriend my local crows for a few months - not sure entirely how long, but it's been a little while. Anyway, they are not coming with any kind of regularity. I have a little camera attached, and it appears the last time one visited was March 2nd. It grabbed a couple of peanuts and flew off.

I have a crow whistle and would initially use it when I set out food, but it didn't seem to make any difference, so I stopped. I used to put out a larger variety of food - unsalted peanuts still in the shell, along with grapes, egg, and other nuts - but they only ever took the peanuts so I only put that out now.

Is it normal for them to only come once every week or two, or should they be coming more often at this point? I really enjoy seeing them and am hoping to befriend the group in my area. It's fairly rural and I always see them flying around every day, so I know they're out there, but just not coming to my house. TIA as I'm still pretty new to all this.