The Collaborative International Dictionary of English v.0.48:

Bird cherry \Bird" cher`ry\ (Bot.)
   A shrub (Prunus Padus ) found in Northern and Central
   Europe. It bears small black cherries.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bird cherry
    n 1: any of several small-fruited cherry trees frequented or fed
         on by birds [syn: bird cherry, bird cherry tree]