Starlings out-compete many native birds, especially hole nesting birds, taking over cavity nests and birdhouses from other species. They also exploit any opening in buildings such as dryer, range and bathroom vents, and gaps around roofs and walls for nesting cavities. Starlings can also transfer many diseases between livestock animals, particularly swine. Starlings have been associated with histoplasmosis, chlamydiosis and salmonellosis and most recently with West Nile virus. Around the home and yard starlings consume a large number of insect pests; however, they can also damage fruit such as grapes, cherries and raspberries and tear open garbage bags.

Starlings consume and contaminate livestock feed and water, and whitewash buildings with their droppings. Large winter flocks of 2,000 starlings in Alberta are known to consume 1 to 2 tons of feed in a month and contaminate or spoil an additional 500 to 1,000 kg of feed. Starlings may also selectively eat the high-protein portion of protein-supplemented livestock feed.