Loud caws of birds coming and going from their favourite roost can disturb the morning peace. It does no good to wait for a "murder" or flock of crows to move on, although some species are migratory, a favourite roost might be occupied for centuries. Messy droppings can be an eyesore. Hunting crows may not be practical or legal, but there are deterrents to limit crow populations.
Use noise. This might be frequent loud noises, either from a bird repellent machine or from firecrackers or pots and pans. A barking dog, preferably one that loves to chase crows, will stop the birds from being a constant presence. If a nesting area or food source is desirable, however, crows will find a way to make use of it out of reach or when the dog is asleep or not looking.
Make a scarecrow. There's a reason scarecrows are so prevalent in nursery rhymes and legends--they work. A lightweight, life-size version is best. A variation on the scarecrow theme is an owl decoy. These can be placed in treetops or the edge of a roof to keep crows away. Large rubber snakes also are quite effective. As with all types of scarecrows, birds eventually figure out it isn't real, especially if it stays in one place. Moving the scarecrow or decoy around helps trick crows into staying away longer, and rotating different looking deterrents may provide better protection.
Use reflections. Crows do not like shiny objects, and they do not like glare. A string of pie tins or old CDs or a few well-placed mirrors that catch the sun and twirl will keep crows from landing nearby.
Fight back with water. Large waterguns, the kind found in toy stores during summer sales, are ideal for shooting crows. It takes some time and commitment (or maybe the enlistment of some young volunteers), but being sprayed with a stream of water will drive crows away. They may not return soon.
Consider killing crows. It is illegal to hunt crows in many states of the U.S. and only allowed with permits in season in others. Obviously, this is not an option for city dwellers. Neighbours may object, and dead birds have to be properly disposed of. When crows are killed in an area they find attractive, more crows will move in to take their place.
Clean up the area. Crows are attracted to garbage and clutter because they are scavengers as well as predators.
Cutting down trees is one way of making a yard less attractive to crows. Removing other vegetation, food and water sources available to these opportunistic birds may make them look elsewhere for comfortable accommodations.
Environmental studies that attempted to increase endangered species by removing predators have shown that ridding an area of crows does not increase other bird populations. It seems the presence of crows balances that of other predators, who will take over when crow populations are depleted.
Crows are intelligent. When they are targets of human wrath, they will come to associate unpleasant behaviour with specific individuals. Harassment by birds may increase, such as cawing at and chasing the people they don't like. They can even recognise and follow cars. As wild birds, crows may be hosts to West Nile Virus. They usually do not spread the disease, which they get from bird-biting mosquitoes, because it kills them. Finding several dead crows may be significant; notify health or wildlife authorities and bag bodies without touching them for proper disposal.