 Where it is introduced , the common starling is unprotected by legislation , and extensive control plans may be initiated . Common starlings can be prevented from using nest boxes by ensuring that the access holes are smaller than the 1 @.@ 5 in ( 38 mm ) diameter they need , and the removal of perches discourages them from visiting bird feeders . 
 Where it is introduced , the common starling is unprotected by legislation , and extensive control plans may be initiated . Common starlings can be prevented from using nest boxes by ensuring that the access holes are smaller than the 1 @.@ 5 in ( 38 mm ) diameter they need , and the removal of perches <a href='uninflect' title='1'><mark>discourages</mark></a> them from visiting bird feeders . 
Where it is introduced , the common starling is unprotected by legislation , and extensive control plans may be initiated . Common starlings can b prevented from using nest boxes by ensuring that the access holes are smaller den the 1 @.@ 5 in ( 38 mm ) diameter they need , and the removal of perches discourage them from visiting bird feeders .