I left /c/Risa because the moderator there was letting his own personal feelings color rules, removing posts that violated no clearly written rules, and creating new rules without even running it past the community or asking how they feel about it.
The moderator of this community is guilty of that same behavior.
I'll be over on !whitepeopletwitter@sh.itjust.works.
I've been feeding crows, magpies, and jackdaws with my partner for a bit over the year. They are now much friendlier towards us, and the pappa crow started flying into our path and standing 1-2 meters away from us to get his snacks.
Here are some other things that helped us be closer to them:
Leaving food outside in a bowl with water, preferably in some high place (a table or chair) so that other animals don't get it. Crows sometimes dip their food in water or like to have a little drink. They will also likely depend on sight rather than smell to find this food, so putting it somewhere where a bird could clearly see nuts or cheese in a bowl could help attract them. Once they find it, they will always remember.
Unsalted Peanuts, walnuts, the ocassional piece of cheese, and sweet red/black grapes -- these things are guaranteed to make crows love you!
Always doing things at the same time every day. Crows are great at telling time and will be waiting for your food if you make it a habit to always restock it in a timely fashion. We go to the park every day around noon (we adjust this for daylight saving time) to feed the crows and magpies and now they follow us from the outside corners of the park and onto the bench -- if we are late, one of them is always scouting and will call the others when we arrive.
Do you have a glass door opening to your yard? If so, and if you have not done this already, try standing behind the glass where they can see you until they are used to your presence. When opening the door, it's good to do it slowly - push down the handle first, then wait, then open the door a bit, then wait, etc. It's the quick motions of doors opening or food being thrown too high that can make crows warry and scared quite quickly.
If you throw them food, are you throwing it high or low? If it goes quite some way above their heads, they might get scared.
What kind of calls have you tried? We have magpies that come to our balcony and (sometimes) respond to a bike bell ring. I keep filling their food bowl then ringing the bike bell... they often show up 5-10 minutes later to get their treat. Have you tried a crow whistle? They can be bought from hunting shops (I don't particularly like giving my money to them, but it's possible to find it in other stores). This video was also helpful but we never got enough practice: https://www.youtube.com/watch?v=TbpE-5sGQBk.
Best of luck with your crow friends. ๐