In fall and winter, starlings often gather in enormous roosts in urban areas. Such roosts are not only a nuisance, but the droppings from thousands of birds can be a potential health hazard. Cities sometimes try to break up winter roosts by playing loud recordings of starling distress calls, firing propane cannons and placing predator decoys nearby. Such methods have had mixed success. Local ordinances should be consulted before attempting any of the noisier techniques.
Starlings compete for nesting sites.
They like sheltered nooks and crannies in old buildings and other structures, but mainly they nest in tree cavities. With only so many cavities to go around, the aggressive starling easily outcompetes native species that nest in cavities. A woodpecker may labor many hours pecking out a new cavity only to be forcibly evicted by starlings. Starlings do have interesting and positive qualities. Their unique bill and jaw muscles work not to clamp the bill shut, but to force it open.