Like a fluttering sparrow or a darting swallow, an undeserved curse does not come to rest. (NIV)
Like the sparrow in her wandering, like the swallow in her flying, so the causeless curse does not alight. [Num. 23:8.] (AMP)
As the bird by wandering, as the swallow by flying, so the curse causeless shall not come. (KJV)