To get rid of crows that frequently invade a trash can, wait for them to leave the trash area, then put a lid on the trash can. They likely won’t keep returning if they can’t gain access. For crows that are creating roosts, the best thing to do is locate the roosts and encourage the crows to move to a different location.
Crows often build roosts in tall trees, near artificial lighting and on the underside of buildings. These areas keep them safe and warm. Some ways to encourage them to leave and relocate include using a loud noisemaker near the roost, using laser lights that annoy the birds but don’t harm them and hanging fake crows near the area.
To keep crows out of a garden, use fabric row covers over seedlings and place bird netting over larger plants and trees. Mylar streamers are effective when spread around the garden. Use wire or fishing line to create a grid around the garden area to deter crows from entering the area. Experts advise against using poison to get rid of crows because poison doesn't cause surviving crows to leave and it can be passed to other animals in the area.